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Lisa Klimas

I'm a 35 year old microbiologist and molecular biologist with systemic mastocytosis, Ehlers Danlos Syndrome, Postural Orthostatic Tachycardia Syndrome, Adrenal Insufficiency, and an assortment of other chronic health issues. My life is pretty much a blast.

January 2015: Post summaries and take home points

Mast cell mutations: JAK2 and myeloproliferative neoplasms

  • JAK2 is a helper protein that helps other molecules send signals to make more cells and to increase inflammation.
  • JAK2 mutation V617F makes some cells more responsive to growth factors, so they grow too much. These cells include red blood cells, platelets and mast cells.
  • Marker associated with other myeloproliferative diseases essential thrombocythemia (too many platelets), polycythemia vera (too many red blood cells), myelofibrosis (fibrosis of bone marrow).
  • About 5% of SM patients have JAK2 V617F mutation. Indicates higher probability of developing another myeloproliferative disease.
  • Doesn’t necessary mean lifespan is shorter.

Heritable mutations in mastocytosis

  • About 75% of MCAD patients have at least one first degree relative with MCAD.
  • The CKIT D816V mutation is not known to be heritable, but other CKIT mutations have been found in multiple family members.

Progression of mast cell diseases (Part 1)

  • Life expectancy with indolent systemic mastocytosis (ISM) is normal.
  • Average age at diagnosis of ISM is 49.
  • Type and severity of symptoms vary and do not correlate with disease type, presence of CKIT D816V mutation or tryptase level.
  • Mediator related symptoms are not indicative of aggressive or progressing disease.
  • Organ swelling is not always indicative of ASM. Organs can be swollen for many years without functional damage or C findings.

Progression of mast cell diseases (Part 2)

  • 5-10 years from diagnosis with ISM, 1.7% of patients progressed to SSM/ASM.
  • 20-25 years from diagnosis with ISM, 8.5% of patients progressed to SSM/ASM.
  • Risk of transformation of ISM to acute leukemia or ASM was less than 1% and 3% respectively.
  • ASM and MCL are associated with accumulation of neoplastic mast cells in organs, impairment of organ function, drug resistance, poor prognosis and organ failure.
  • In most SSM patients, disease stays stable over years or decades.
  • SSM patients have higher incidence of anemia, constitutional symptoms and mast cell mediator levels than ISM patients.
  • SSM is diagnosed later than ISM, around 64 years.
  • ASM can be slow progressing and stable for many years or rapidly progressing.
  • During progression of ASM and MCL, some patients lose the CKIT D816V mutation.
  • Slow progression ASM can be kept under control for several months or even years with interferon and cladribine.
  • In a group of 342 patients, 0.6% ISM patients developed MCL or AML, 6.5% ASM, and 13% SM-AHNMD.
  • It is possible for disease to convert to less severe category.

Progression of mast cell diseases (Part 3)

  • Mast cell accumulation is mostly due to decrease in apoptosis (cell death) rather than excessive proliferation.
  • 20-30% of SM patients have tryptase below 20 ng/ml.
  • If you test negative for CKIT D816V in blood, you may still be positive.
  • Bone marrow test for CKIT D816V is most accurate.
  • Histamine intolerance has been proposed as deficiency of enzymes to metabolize histamine. There is no evidence that this occurs in mast cell disease.
  • 33% of MCAS patients are positive for elevated tryptase, 56% n-methylhistamine, 44% PGD2.
  • 66% of patients with MCAS have major or complete regression in symptoms after one year of treatment.

Progression of mast cell diseases (Part 4)

  • ISM is not life threatening in and of itself. Anaphylaxis, a symptom of ISM, is life threatening.
  • 49% of SM patients experience anaphylaxis in their lifetime. 48% of anaphylaxis episodes in ISM patients were severe.
  • There is no consensus on what is a normal count of mast cells in GI tract. Some healthy patients have more than 20 mast cells/hpf.
  • Most patients with adult onset cutaneous mastocytosis also have systemic mastocytosis.
  • Early studies indicated CM and MCAD were different, but frequency of CKIT mutations the same in patients with CM, SM and MCAS (about 86% in each group in one study). NOTE: The CKIT mutations were not always the D816V mutation.
  • Patients with MMAS (monoclonal mast cell activation syndrome) and MCAS (mast cell activation syndrome) never have CM.
  • ASM and MCL patients frequently lack CM.

Progression of mast cell diseases (Part 5)

  • 55% of pediatric mastocytosis cases occur in the first two years of life.
  • 35% occur between ages of 15 and 18.
  • Cutaneous mastocytosis can result in mediator release symptoms without having systemic mastocytosis.
  • 2/3 of childhood mastocytosis patients had complete resolution of cutaneous disease and symptoms before adulthood. They were not treated with steroids, PUVA or chemo drugs.
  • Bone marrow biopsies of children with CM often show more mast cells than normal. High bone marrow mast cells in these children does not affect resolution.
  • In a study of 50 pediatric CM patients, 86% had a CKIT mutation and36% had the D816V mutation.

Mast cell mutations: TET2 and mutation profiles of aggressive subtypes

  • TET2 is mutated in 20.8-29% of SM patients.
  • Several mutations are seen.
  • TET2 is involved in DNA methylation which affects gene expression.
  • 96% of SM patients with major blood abnormalities had mutations in at least two genes regardless of SM subtype.

Mast cell mutations: SRSF2 in SM-AHNMD

  • SRSF2 is a protein that affects gene expression.
  • An SRSF2 mutation was found in 24-37% of SM patients.
  • Most common mutation in SM after CKIT D816V.
  • Strongly associated with SM-AHNMD.
  • Also found in other cell types besides mast cells. In SM-AHNMD, may cause both mast cell disease and associated blood disorder.

Anticholinergic use and dementia

  • People who took higher amounts of anticholinergics had an increased risk of dementia.
  • Some medications used to treat mast cell disease are strong anticholinergics, like diphenhydramine and doxepin.
  • It is not clear if the medications caused dementia or if the conditions that required those medications caused dementia.

Mast cells in wound healing

One of the most well described non-allergic functions of the mast cell is wound healing. Mast cells are involved in many functions integral to remodeling and closing wounds.

Immediately following formation of a wound, signals are sent to constrict vessels near the injury to decrease the risk of bleeding and infection. After bleeding has been minimized, the blood vessels become a little more permeable to let cells and molecules from the bloodstream into the injured area in order to promote healing and prevent infection. These actions activate the complement clotting system, which produces molecules C3a and C5a. These molecules bind to mast cells and induce degranulation.

Following degranulation, vessels become more permeable through the action of histamine and other mediators. Fibrinogen, important in clot formation, leaves the blood stream and accumulates in the tissue. This triggers thrombin to change fibrinogen to fibrin, forming a clot. Mast cells are active in preventing excessive clotting. Tryptase and heparin are released from granules bound together, and this complex degrades fibrogen and inactivates thrombin.

The extracellular matrix is the structures which give substance to groups of cells and vessels. Following wound formation, fibronectin and type III collagen molecules gather near the injury. Mast cell proteases chymase and tryptase break down the extracellular matrix molecules to make room for newly made cells to close the wound. It is also possible that mast cell mediator CMA1 breaks down fibronectin.

Granulation tissue forms when wounds are healing. Granulation involves several activities, such as cell proliferation, develop of blood vessels, and building of new skin. Fibroblasts, which make collagen and extracellular matrix molecules, are drawn to the injury by mast cell signaling. Once there, they are induced to proliferate by action of the presence of histamine, tryptase, heparin and fibroblast growth factor. Mast cell degranulation also drives generation of new blood vessels through action of histamine, heparin, chymase, fibroblast growth factor, VEGF and tumor necrosis factor. Formation and proliferation of new epithelial tissue is also encouraged by TGF-b1, histamine, IL-1a, IL-1b, IL-6, tryptase, and heparin.

Once enough new cells have been made, the fibroblasts become myofibroblasts to make new muscle. Histamine and tryptase mediate this step. The fibroblasts directly interact with mast cells. Mast cell proteases tryptase and chymase trigger the activation of several molecules that mediate remodeling of the extracellular matrix. The wound is closed following this remodeling and laying down of new skin.

References:

Douaiher, Jeffrey, et al. Development of Mast Cells and Importance of Their Tryptase and Chymase Serine Proteases in Inflammation and Wound Healing Advances in Immunology, Volume 122 (2014): Chapter 6.

Christine Möller Westerberg, Erik Ullerås, Gunnar Nilsson. Differentiation of mast cell subpopulations from mouse embryonic stem cells. Journal of Immunological Methods 382 (2012) 160–166.

 

 

 

The high water mark

I spent most of the latter half of May in bed. People woke me up take medication on schedule and I fed myself small meals periodically. I watched movies and TV and drifted in and out of sleep, pain killers and Benadryl making the world soft around the edges.

Every day, even as I felt myself healing, my strength and stamina waned. My legs felt weak when I stood up. I got winded walking around the block. Holding my head up felt difficult. All of the stamina I had built up before surgery was gone. All of my progress was undone.

I spend so much energy trying to get somewhere I’m never going to get – to this place of physical health where I can exercise and sleep at night and wake in the morning without bleary eyes and a pounding headache. I have been trying to reach this milestone since well before I knew I was sick.

I’m not even sure I know the closest I ever came. What is the highwater mark of this particular struggle? Was it the few weeks before my last birthday when I was sleeping at night and waking without an alarm? Or that really good day last September? The few weeks after my colostomy healed? I don’t know. I’m not sure there is a high water mark. Everything is relative.

Living with a sickness that causes regular setbacks – and requires treatments that sometimes do the same – is difficult. This halting start has become a sort of rhythm, the timing an inherent part of this experience. I’m never getting anywhere. I’m always getting it wrong. It feels like if I could do the right things in the right order that it would make a difference. `

But what if every time I started again, it didn’t mean that every time before was a failure? All those times before, all the moves in the wrong order, kept me alive and participating in the world. How wrong could they be? What if the high water mark of this struggle is just being alive?

Reversing the ostomy was the right move. I am noticeably less inflamed and my body is responding. I am having fewer reactions. I am eating without vomiting. The squishiness, the swelling weight is melting away so I can see the features beneath. I am still in pain, but I think I always will be.

I’m getting stronger. It’s slow, but it’s happening. I can walk for twenty minutes now, Astoria happily padding along beside me. I’m short of breath and sweaty when I’m done, but I can do it.

Maybe it’s time to stop blaming myself for all the times I had to start over. Maybe it’s time to see these setbacks as opportunities to understand my body and learn from it.

Maybe this is enough.

 

Angioedema: Part 4

Deficiencies of an early component of the classical complement pathway (C1q, C1r, C1s, C2, C4) have been associated with lupus like autoimmune conditions. The reason for this is that these proteins help to clean up large groups of molecules called immune complexes before they can cause inflammation. Dead cells are also removed by these complement molecules. Without these proteins, immune complexes and dead cells are not removed and cause local irritation.

In HAE types I and II, complement proteins C2 and C4 are low. However, HAE patients have been shown to have a normal level of immune complexes. For this reason, it is still unclear whether or not low C2 and C4 may contribute to overall inflammation and pain profile for these patients. Despite this fact, it is still possible that deficiency in C2 and C4 may predispose HAE patients to autoimmune diseases.

A number of studies have assessed the prevalence of autoimmune conditions in HAE patients. One study looked specifically for two thyroid antibodies and found that 13.2% HAE patients had autoantibodies to the thyroid.

When expanding the autoimmune profile to include “lupus-like” conditions such as those often associated with complement deficiencies, a much higher prevalence of autoantibodies was found in HAE patients. Three other studies measured the frequency of ANA (anti-nuclear antibody, a generic marker found in many autoimmune conditions); RF (Rheumatoid Factor, associated with rheumatoid arthritis); anti-thyroglobulin(autoimmune thyroiditis); TPO (thyroid peroxidase, autoimmune thyroiditis); and thyroid antibodies along with some or all of the following antibodies: anti-dsDNA (anti double stranded DNA, systemic lupus erythematosus); ENA (extractable nuclear antigens, a panel of six tests that can identify mixed connective tissue disease, systemic lupus erythematosus, Sjogren’s, Scleroderma and dermatomyositis); TMA (microsomal antibodies, autoimmune thyroiditis); AMA (antimitochondrial antibodies, drug-induced or systemic lupus erythematosus, Sjogren’s, autoimmune hemolytic anemia, autoimmune liver disease); ANCA (antineutrophil cytoplasmic antibodies); anti-cardiolipin (systemic lupus erythematosus, Behcet’s, antiphospholipid syndrome); anti-b2GPI (b2-glycoprotein I, systemic lupus erythematosus, Behcet’s, antiphospholipid syndrome); anti-C1q (urticarial vasculitis); anti-P ribosomal (systemic lupus erythmatosis); EMA (anti-endomysial antibodies, Celiac disease); tTG (anti-tissue transglutaminase antibodies, dermatitis herpetiformis); and ASCA (anti-saccharomyces cerevisiae antibodies, Behcet’s, Celiac disease, Crohn’s disease, ulcerative colitis). The three studies found that 47.5-48% HAE patients had at least one of these autoantibodies. In comparison, the average for healthy controls was 10%.

Other studies looked at prevalence of autoimmune disease rather than autoantibodies. One study found that 12% of HAE patients had at one of the following autoimmune conditions: glomerulonephritis, Sjogren’s syndrome, irritable bowel disease, thyroiditis, systemic lupus erythematosus, rheumatoid arthritis, drug induced lupus, pernicious anemia, juvenile RA with IgA deficiency, or sicca syndrome.

Other studies found that 3.4% HAE patients had lupus rash or glomerulonephritis; that 0.9% had RA or Sjogren’s; that 11.5% had Crohn’s, Celiac, Hashimoto’s thyroiditis, discoid lupus erythematosus, chronic lymphocytic leukemia, MGUS, or IgA deficiency; that 11.4% had systemic lupus erythematosus, Celiac, multiple sclerosis-like syndrome, systemic sclerosis, or mixed connective tissue disease; that 4.2% had lupus like syndrome, psoriatic arthritis, mixed connective tissue disease or antiphospholipid syndrome; that 0.4-0.9% had lupus-like or unspecific cutaneous lupus or subacute lupus.

An interesting feature of HAE is the frequent complaint of decreased sense of smell. Facial edema and chronic rhinosinusitis were not found to be the cause. However, systemic lupus erythematosus and Sjogren’s syndrome can also cause impairment of smell. Despite the frequency of lupus in HAE patients, it usually affected the mucocutaneous regions of the body and was generally mild.

In addition to the frequent prevalence of autoantibodies and autoimmune disease, HAE patients have increased B cell activation and autoreactive B cells. This can also contribute to an inflammatory and autoimmune profile.

 

References:

Kaplan AP, et al. Pathogenic mechanisms of bradykinin mediated diseases: dysregulation of an innate inflammation pathway. Adv Immunol 2014; 121:41-89.

Kaplan AP, et al. The plasma bradykinin-forming pathways and its interrelationships with complement. Mol Immunol 2010 Aug; 47(13):2161-9.

Firinu, Davide, et al. Characterization of patients with angioedema without wheals: the importance of F12 gene screening. Clinical Immunology (2015) 157, 239-248.

Csuka, Dorottya, et al. Activation of the ficolin-lectin pathway during attacks of hereditary angioedema. J Allergy Clin Immunol 134 (6) 1388-1393.e3.

Triggianese, Paola, et al. The autoimmune side of hereditary angioedema: insights on the pathogenesis. Autoimmunity Reviews 2015 (ahead of press).

 

 

 

 

Angioedema: Part 3

Acquired angioedema (AAE) is characterized by a deficiency of C1INH not associated with a genetic defect; overactivation of the classical complement pathway; and frequent angioedema episodes. AAE is rare, about ten times less common than HAE. However, the two conditions are clinically identical. AAE often presents with low CH50, C2, C4 and sometimes C1q, with low or poorly functioning C1INH.

AAE was originally associated with lymphoma and has since been found secondary to a number of autoimmune and hematologic diseases, particularly lymphoproliferative conditions and monoclonal gammopathy of unknown significance (MGUS, which often precedes multiple myeloma). Historically, AAE has been divided into two groups: type I, which I just described; and type II, in which there are IgG antibodies to C1INH that inactivate C1INH. However, further research found that anti-C1INH antibodies are also found in type I. It has since been recognized that these are really different presentations of the same condition, with lymphoma cells depleting C1INH more readily. There have been documented instances in which achieving remission from lymphoma cured the associated AAE.

There are other types of angioedema that are difficult to classify. Idiopathic angioedema is the instance of three episodes in 6-12 months without a clear trigger or pathology. It is distinguished from hereditary angioedema by the shorter duration of symptoms. Further testing demonstrates normal levels and function of C1INH in these patients. This is sometimes called “idiopathic non-histaminergic AAE” to distinguish from an allergic process.

Type III HAE patients are sometimes positive for mutations in the Factor XII gene. However, in some patients, no mutation is found. All type III patients demonstrate normal level and function of C1INH. Type III patients experienced four attacks per year on average, with 42.9% having swelling in the airway. 85% had abdominal attacks, with some severe enough to result in emergency (though unnecessary) surgical procedures and ascites, free fluid in the abdomen.

In the patients with the Factor XII mutation, attacks were most likely to occur during high estrogen states, but were not exclusive to these periods. Initial attacks for this patient group usually occurred while on oral contraceptives or during pregnancy. However, men and children were also found to have Factor XII mutations. Initial attacks were less likely to affected by estrogen state in type III HAE with no FXII mutation or in idiopathic non-histaminergic angioedema. .

23% of type III patients exhibited elevated D-dimer levels outside of attack periods. Some also had extended clotting times. In the FXII mutated group, bruising was seen in a number of patients when swelling in the swollen portions of anatomy, but strictly in the skin. 27.9% of pregnancies in this group terminated in spontaneous miscarriage. Two births were extremely premature and one liveborn child died shortly after birth with no obvious cause of death.

References:

Zuraw, B. L., et al. A focused parameter update : Hereditary angioedema, acquired C1 inhibitor deficiency, and angiotensin-converting enzyme inhibitor-associated angioedema. J Allergy Clin Immunol 2013; 131(6); 1491-1493e25.

Kaplan AP, et al. Pathogenic mechanisms of bradykinin mediated diseases: dysregulation of an innate inflammation pathway. Adv Immunol 2014; 121:41-89.

Kaplan AP, et al. The plasma bradykinin-forming pathways and its interrelationships with complement. Mol Immunol 2010 Aug; 47(13):2161-9.

Firinu, Davide, et al. Characterization of patients with angioedema without wheals: the importance of F12 gene screening. Clinical Immunology (2015) 157, 239-248.

Csuka, Dorottya, et al. Activation of the ficolin-lectin pathway during attacks of hereditary angioedema. J Allergy Clin Immunol 134 (6) 1388-1393.e3.

Ohsawa, Isao, et al. Clinical manifestations, diagnosis, and treatment of hereditary angioedema: survey data from 94 physicians in Japan. Ann Allergy Asthma Immunol 114 (2015) 492-498.

Kajdacsi, E., et al. Endothelial cell activation during edematous attacks of hereditary angioedema types I and II. J Allergy Clin Immunol 133 (6); 1686-1691.

Triggianese, Paola, et al. The autoimmune side of hereditary angioedema: insights on the pathogenesis. Autoimmunity Reviews 2015 (ahead of press).

Madsen, Daniel Elenius, et al. C1-inhibitor polymers activate the FXII-dependent kallikrein-kinin system: implication for a role in hereditary angioedema. Biochimica and Biophysica Act 1850 (2015) 1336-1342.

Lasek-Bal, Anetta, et al. Hereditary angioedema with dominant cerebral symptoms finally leading to chronic disability. Clinical Neurology and Neurosurgery 135 (2015) 38-40.

 

 

 

Angioedema: Part 2

Patients with HAE may have normal bloodwork for routine tests. Blood counts, electrolytes and liver function tests are often unremarkable. Upon further testing, complement protein C4 is often low. This deficiency is most profound during attacks but often continues in interim periods. C3 is usually normal.

  • In HAE type I, C1 inhibitor (C1INH), C4 and C2 levels are low, while C1q is normal.
  • In HAE type II, C1INH is normal or marginally increased, C4 and C2 levels are low, and C1q is normal. C1INH functional tests yield low function.
  • In HAE type III, CIINH is normal and functions normally and C4 is sometimes normal. Mutation for Factor XII is sometimes found. This is still largely a diagnosis of exclusion based upon similar clinical presentation as the other two types.

Hereditary angioedema (HAE) attacks carry the risk of significant danger as airway constriction can lead to suffocation. More than half of HAE patients will experience laryngeal swelling at least once in their lifetime. Swells typically last 2-3 days and then resolve over the following two days. Antihistamines and steroids are ineffective in mitigating swelling of this type.

HAE attacks have many triggers in the same way mast cell disease does. HAE was originally termed angioneurotic disease because patients frequently had a strong emotional event that activated the disease. In women, swells may correspond to changes in circulatory estrogen – pregnancy, menopause, puberty, menses. Psychological stress is a well characterized trigger for HAE and patients are strongly urged to eliminate sources of stress wherever possible. ACE inhibitors are known to interfere with regulation of the pathway to produce bradykinin and should therefore by avoided.

The last few years have seen several medications for acute angioedema attacks come to market. Cinryze, Berinert and Ruconest are C1INH solutions for intravenous infusion that can be administered at home. Kalbitor is a kallikrein inhibitor that is formulated for subcutaneous injection. Firazyr blocks the bradykinin receptor and is also available for injection. It is universally agreed that these medications should be available on demand in the event of a swell as they have been shown to safely and effectively reduce the risk to life.

With the advent of these targeted medications, more outmoded treatments are start to be phased out. Previous treatment modalities include fresh frozen plasma for acute attacks or short term prophylaxis, anabolic steroids like anabolic steroids, such as danazol, and antifibrinolytic medications, such as tranexamic acid. These medications often had difficult side effects, but still see some use for prophylaxis to avoid swell episodes. For short term prophylaxis for procedures, 1000-2000U of C1INH, 2U of freshly frozen plasma or a week of high dose danazol can be used.

References:

Zuraw, B. L., et al. A focused parameter update : Hereditary angioedema, acquired C1 inhibitor deficiency, and angiotensin-converting enzyme inhibitor-associated angioedema. J Allergy Clin Immunol 2013; 131(6); 1491-1493e25.

Kaplan AP, et al. Pathogenic mechanisms of bradykinin mediated diseases: dysregulation of an innate inflammation pathway. Adv Immunol 2014; 121:41-89.

Kaplan AP, et al. The plasma bradykinin-forming pathways and its interrelationships with complement. Mol Immunol 2010 Aug; 47(13):2161-9.

Firinu, Davide, et al. Characterization of patients with angioedema without wheals: the importance of F12 gene screening. Clinical Immunology (2015) 157, 239-248.

Csuka, Dorottya, et al. Activation of the ficolin-lectin pathway during attacks of hereditary angioedema. J Allergy Clin Immunol 134 (6) 1388-1393.e3.

Ohsawa, Isao, et al. Clinical manifestations, diagnosis, and treatment of hereditary angioedema: survey data from 94 physicians in Japan. Ann Allergy Asthma Immunol 114 (2015) 492-498.

Kajdacsi, E., et al. Endothelial cell activation during edematous attacks of hereditary angioedema types I and II. J Allergy Clin Immunol 133 (6); 1686-1691.

Triggianese, Paola, et al. The autoimmune side of hereditary angioedema: insights on the pathogenesis. Autoimmunity Reviews 2015 (ahead of press).

Madsen, Daniel Elenius, et al. C1-inhibitor polymers activate the FXII-dependent kallikrein-kinin system: implication for a role in hereditary angioedema. Biochimica and Biophysica Act 1850 (2015) 1336-1342.

Lasek-Bal, Anetta, et al. Hereditary angioedema with dominant cerebral symptoms finally leading to chronic disability. Clinical Neurology and Neurosurgery 135 (2015) 38-40.

 

 

 

Administrative stuff

Hey, everyone –

Just a quick note about administrative stuff.

I am getting a lot of emails, FB messages and blog comments with questions from patients and providers.  This is fantastic!  I had GI surgery last month and am still in the process of recuperating.  I am responding to questions as I am able, but it will take me a bit to get through the backlog.  I appreciate your patience.

I am pretty accessible via the MastAttack Facebook group and have answered tons of questions there.  Additionally, there are lots of other people in that group who are veteran mast cell patients and/or subject matter experts on mast cell disease, dysautonomia or any number of other topics.  Feel free to join if you like.

I have had some questions about whether or not I take requests for posts.  I sure do.  If there is something you are dying to know about, just let me know.  My turnaround time is usually a few weeks.

Everyone seems to like my “master table” posts.  I have a bunch of these that I use for quick reference.  Since people find them helpful, I will upload some more.  These are living documents and will be updated as I find new information.  Likewise, if you have a helpful addition to a master table, let me know.

Some patients have told me that in the past few months, some of my posts are more “sciency” and it’s less easy to understand.  I agree that this is the case.  The purpose of these posts is for you to provide articles with references to providers, and for providers to be able to utilize this site as a source of easy to digest information.  I am considering doing some simplified posts on specific topics for patients.  I am not completely sure yet how I will do this.

MastAttack was started for the purpose of making information about these diseases accessible to the patients who live with them.  To that end, I will find a solution to make sure patients can come here and feel comfortable in their understanding.

Thanks for your patience while I get back up to speed.  I feel really fortunate to have such interested and thoughtful readers.  You guys are the best!

Lisa

Angioedema: Part 1

Hereditary angioedema (HAE) is a heritable blood disorder that causes episodes of protracted swelling, which can be life threatening. It has three subtypes, with two known to be caused by a mutation in the C1-INH (C1 inhibitor) gene.

HAE causes angioedema, a condition in which fluid leaves the bloodstream and passes into the space between the deep dermis and subcutaneous tissue. Swelling episodes can last for up to five days and swelling resolves between attacks. About 30% of HAE patients also have a rash similar to erythema marginatum, pink, slightly raised rings that don’t itch or wheal. HAE patients do not have hives or itching, an important distinction that allows diagnostic separation from chronic urticaria and angioedema

Swelling can occur in any region of the body, but face, GI tract, limbs, penis and scrotum are the most common. Angioedema of the tongue and pharynx can compromise the airway, as can edema of the larynx. In these patients, a tracheostomy may need to be placed.

Over 90% of patients suffer severe abdominal swells lasting 2-4 days. Abdominal pain, nausea, vomiting and diarrhea are common symptoms in this group. It is not unusual for doctors to assess the patient as having an “acute abdomen” in need of surgical intervention. Likewise, unnecessary surgery is often performed looking for the source of the swelling. These symptoms occur as a result of edema in the bowel wall, with complete or partial obstruction, sometimes causing ascites, or free fluid in the abdomen.

Angioedema seen in HAE patients is caused by excessive production of bradykinin, which is initiated by factor XII (also called Hageman factor). There are three types of HAE:

  • Patients with HAE type I (85% of cases) have too little C1 inhibitor which functions poorly.
  • Patients with type II (15% of cases) have normal levels of C1 inhibitor but it does not function correctly.
  • Patients with HAE type III have normal levels and function of C1 inhibitor, but have symptoms and treatment responses similar to those with types I and II. Current research indicates that these people sometimes have mutations in the gene for Factor XII, which is also involved in the production of bradykinin.

Bradykinin acts on B2 receptors to cause blood vessels to dilate, decreasing blood pressure. It also increases vessel permeability, allowing fluid and cells to leave the blood stream and become trapped in tissues, resulting in angioedema.

C1 inhibitor (C1INH) is a molecule with multiple regulatory functions. Its name derives from its relation to the complement protein C1, the activation of which is the initiating step in the classical pathway for the complement system, a mechanism for fighting infections. A side product of this pathway is the large scale production of complement proteins C3a and C5a, both of which can induce anaphylaxis. C1INH also regulates steps involving the formation of plasminogen and plasmin, which prevent the formation of blood clots.

C1INH also inhibits the molecule Factor XII, also called Hageman Factor. C1INH prevents Factor XII from activating itself, the first step in a pathway that produces bradykinin. Activation of Factor XII causes formation of molecules XIIa and XIIf. Factor XIIa induces conversion of prekallikrein to kallikrein, and kallikrein then acts on high molecular weight kininogen to release bradykinin. All of those steps are regulated by C1INH.

 

References:

Zuraw, B. L., et al. A focused parameter update : Hereditary angioedema, acquired C1 inhibitor deficiency, and angiotensin-converting enzyme inhibitor-associated angioedema. J Allergy Clin Immunol 2013; 131(6); 1491-1493e25.

Kaplan AP, et al. Pathogenic mechanisms of bradykinin mediated diseases: dysregulation of an innate inflammation pathway. Adv Immunol 2014; 121:41-89.

Kaplan AP, et al. The plasma bradykinin-forming pathways and its interrelationships with complement. Mol Immunol 2010 Aug; 47(13):2161-9.

Firinu, Davide, et al. Characterization of patients with angioedema without wheals: the importance of F12 gene screening. Clinical Immunology (2015) 157, 239-248.

Csuka, Dorottya, et al. Activation of the ficolin-lectin pathway during attacks of hereditary angioedema. J Allergy Clin Immunol 134 (6) 1388-1393.e3.

Ohsawa, Isao, et al. Clinical manifestations, diagnosis, and treatment of hereditary angioedema: survey data from 94 physicians in Japan. Ann Allergy Asthma Immunol 114 (2015) 492-498.

Kajdacsi, E., et al. Endothelial cell activation during edematous attacks of hereditary angioedema types I and II. J Allergy Clin Immunol 133 (6); 1686-1691.

Triggianese, Paola, et al. The autoimmune side of hereditary angioedema: insights on the pathogenesis. Autoimmunity Reviews 2015 (ahead of press).

Madsen, Daniel Elenius, et al. C1-inhibitor polymers activate the FXII-dependent kallikrein-kinin system: implication for a role in hereditary angioedema. Biochimica and Biophysica Act 1850 (2015) 1336-1342.

Lasek-Bal, Anetta, et al. Hereditary angioedema with dominant cerebral symptoms finally leading to chronic disability. Clinical Neurology and Neurosurgery 135 (2015) 38-40.

 

 

 

Activating the complement system: Classical, alternative and lectin pathways

The complement system is part of the innate immune system, meaning it does not “learn” over time by being exposed to organisms, and its behavior is the same throughout life. This system is made up of many small proteins that are manufactured in the liver and then released into the bloodstream. Importantly, these proteins are in an inactive state when they move out of the liver. To be active, these proteins have to be “cleaved” or have pieces of the molecule cut off. This is done by other proteins when specific signals are detected.

The complement system undergoes large scale amplification, meaning many, many proteins can be cleaved to fight infection from only one small signal. Once there are many complement proteins to help, they help to kill microbes by building a tunnel through the cell membrane. This tunnel is called the membrane attack complex (MAC).

There are three methods for activating the complement system, all of which involve several steps and several molecules.  It is crucial that these complements are present in the correct ratio or it can contribute to inflammation and disease.

The classical pathway is activated in one of three ways:

  1. Activation:
  • An antibody binds to the outside of microbe. This can be done by certain types of IgG (but not IgG4) or IgM.
  • The enzyme C1 can also bind to the surface of some microbes.
  • C-reactive protein can also activate the classical system by binding to some microbial products.
  1. In the blood, C1 is actually made up of three small parts called subunits: C1q, C1r and C1s. The C1q binds to the antibody on the surface of the microbe. This activates the subunits.
  2. C1s cleaves C4 into two pieces. C4b binds to the cell surface of the microbes. C4a has no function here and is broken down after being released.
  3. C1s cleaves C2 into two pieces. C2b binds to C4b, which is bound to the cell surface. C2a has no function here and is broken down after being released.
  4. When C4b and C2b are bound together, they are called C3 convertase and they perform the special function of cleaves C3. C3 is cleaved into two pieces.
  5. C3b binds to various places on the cell surface. Macrophages and neutrophils (immune cells) can bind to C3b. When macrophages bind to C3b, it may then phagocytose (or eat) the microbe. C3b can also bind to C5, which allows it to be cleaved by C3/C5 convertase.
  6. C3a is an anaphylatoxin. (I have written a previous detailed post on this). It can trigger basophils and mast cells to degranulate.
  7. C5 is cleaved by C3/C5 convertase. This release C5a and C5b.
  8. C5a is a very strong anaphylatoxin and also attracts neutrophils to fight infections.
  9. C5b is the anchor for the membrane attack complex. C6, C7, C8 and several molecules of C9 form a long line on molecules that pokes a whole in the membrane of the microbe. If the membrane is broken, water will rush into the cell and the cell will not function correctly. This results in cell death.

The alternative pathway is activated as follows:

  1. C3 can turn itself into the molecule C3b. This is spontaneous and does not require any other molecules. C3b is short lived under normal circumstances.
  2. If a microbe is nearby, C3b will bind to a molecule on the microbial surface called Factor B.
  3. C3b and Factor B bound together are a different kind of C3 convertase than the one described for classical pathway. This C3 convertase cleaves other molecules.
  4. C3b-Factor B, a C3 convertase, cleaves a molecule of C3.
  5. The liberated molecule of C3b binds to C3b-Factor B-C3b. This is a C5 convertase, which starts the membrane attack complex.
  6. While the MAC is being made, this C5 convertase is still cleaving C3 to release large amounts of C3b.

The lectin pathway is activated as follows:

  1. MBL and ficolin bind to microbial surfaces.
  2. This activates the molecule MASP-2.
  3. MASP-2 cleaves C4 and C2, forming a grouping of molecules called the terminal complement complex (TCC).
  4. C1s cleaves C2 into two pieces. C2b binds to C4b, which is bound to the cell surface. C2a has no function here and is broken down after being released.
  5. When C4b and C2b are bound together, they are called C3 convertase and they perform the special function of cleaves C3. C3 is cleaved into two pieces.
  6. C3b binds to various places on the cell surface. Macrophages and neutrophils (immune cells) can bind to C3b. When macrophages bind to C3b, it may then phagocytose (or eat) the microbe. C3b can also bind to C5, which allows it to be cleaved by C3/C5 convertase.
  7. C3a is an anaphylatoxin. (I have written a previous detailed post on this). It can trigger basophils and mast cells to degranulate.
  8. C5 is cleaved by C3/C5 convertase. This release C5a and C5b.
  9. C5a is a very strong anaphylatoxin and also attracts neutrophils to fight infections.
  10. C5b is the anchor for the membrane attack complex. C6, C7, C8 and several molecules of C9 form a long line on molecules that pokes a whole in the membrane of the microbe. If the membrane is broken, water will rush into the cell and the cell will not function correctly. This results in cell death.

 

Some molecules control the complement system so that the amplification does not cause problems.

  • Factor H controls the alternative pathway. It helps to degrade the C3b-Factor B-C3b complex.
  • Factor I converts C3b to an inactive form.
  • C1INH (C1 inhibitor) binds to activated C1r and C1s, making them inactive. This happens quickly, so there is only a brief time before C1INH binds to C1r or C1s during which they can cleave C4 and C2.

 

 

 

Master table of de novo mast cell mediators

 

Mediator Symptoms Pathophysiology
b-FGF (basic fibroblast growth factor) Angiogenesis, proliferation, wound healing, binds heparin
GM-CSF (granulocyte macrophage colony stimulating factor) Rheumatoid arthritis Induces stem cells to make granulocytes and monocycles
IL-1a Fever, insulin resistance, inflammatory pain Activates TNFa, stimulates production of PGE2, nitric oxide, IL-8 and other chemokines
IL-1b Pain, hypersensitivity Autoinflammatory syndromes, regulates cell proliferation, differentiation and death, induces COX2 activity to produce inflammatory molecules
IL-2 Itchiness, psoriasis Regulates T cell differentiation
IL-3 Drives differentiation of several cell types, including mast cells, and proliferation
IL-4 Airway inflammation, allergic asthma Regulates T cell differentiation
IL-5 Eosinophilic allergic disease Activates eosinophils, stimulates proliferation of B cells and antibody secretion, heavily involved in eosinophilic allergic disease
IL-6 Fever, acute phase inflammation, osteoporosis Inhibits TNFa and IL-1, stimulates bone resorption, reduces inflammation in muscle during exercise
IL-9 Asthma, bronchial hypersensitivity Increases cell proliferation and impedes apoptosis of hematopoietic cells
IL-10 Regulates the JAK-STAT pathway, interferes with production of interferons and TNFa.   Exercise increases levels of IL-10
IL-13 Airway disease, goblet cell metaplasia, oversecretion of mucus Induces IgE release from B cells, links allergic inflammation to non-immune cells
IL-16 Allergic asthma, rheumatoid arthritis, Crohn’s disease Attracts activated T cells to inflamed spaces,
IL-18 Linked to several autoimmune and inflammatory conditions, including Hashimoto’s thyroiditis Induces release of interferon-g, causes severe inflammatory reactions
Interferon-a Flu like symptoms, malaise, muscle soreness, fever, sore throat, nausea Inhibition of mast cell growth and activity
Interferon-b Flu like symptoms, malaise, muscle soreness, fever, sore throat, nausea Inhibition of mast cell growth and activity
Interferon-g Granuloma formation, chronic asthma Induces production of nitric oxide, IgG2a and IgG3 from B cells, increases production of histamine, airway reactivity and inflammation
Leukotriene B4 Mucus secretion, bronchoconstriction, vascular instability, pain Draws white cells to site of inflammation
Leukotriene C4 Mucus secretion, bronchoconstriction, vascular instability, pain Draws white cells to site of inflammation
MCP-1 Neuroinflammation, diseases of neuronal degeneration, glomerulonephritis Draws white blood cells to inflamed spaces,
MIF (macrophage migration inhibitory factor) Regulate acute immune response, release triggered by steroids
MIP-1a (macrophage inflammatory protein) Fibrosis Activates granulocytes, nduces release of IL-1, IL-6 and TNFa
Neurotrophin-3 Nerve growth factor
NGF (nerve growth factor) Regulates survival and growth of nerve cells, suppresses inflammation
Nitric oxide Bruising, hematoma formation, excessive bleeding Vasodilation, inhibition of platelet aggregation
PDGF (platelet derived growth factor) Platelet growth factor, growth of blood vessels, wound healing
Platelet activating factor Constriction of airway; urticaria; pain Platelet activation and aggregation, vasodilation
Prostaglandin D2 Flushing, mucus secretion, bronchoconstriction, vascular instability, mixed organic brain syndrome, nausea, abdominal pain, neuropsych symptoms, nerve pain Inflammation, pain, bronchoconstriction
Prostaglandin E2 Muscle contractions, cough Draws white blood cells to site of inflammation
RANTES (CCL5) Osteoarthritis Attracts white cells to inflamed spaces, causes proliferation of some white cells
SCF (stem cell factor) Regulates mast cell life cycle, induces histamine release
TGFb (transforming growth factor beta) Bronchial asthma, heart disease, lung fibrosis, telangiectasia, Marfan syndrome, vascular Ehlers syndrome syndrome Regulates vascular and connective tissues
TNFa (tumor necrosis factor) Fever, weight loss, fatigue Regulates death of cells and acute inflammation
VEGF (vascular endothelial growth factor) Bronchial asthma, diabetes Angiogenesis, draws white cells to inflamed spaces, vasodilation