Serum levels of neutrophil and eosinophil chemotactic activities in mastocytosis

Neutrophil and eosinophil chemotactic activities (NCA and ECA) were measured in serum from twenty-two patients with urticaria pigmentosa or systemic mastocytosis. NCA was also measured after heating serum to 56°C (heat-stable NCA). Although these factors were increased in about half of the patients there was no correlation with histamine release as estimated by the excretion of the main histamine metabolite methylimidazoleacetic acid (MelmAA) in urine. A significant increase in heat-stable NCA, however, was found in patients with pruritus and abnormal high values of MelmAA. It is concluded that only heat-stable NCA is a specific mast cell mediator, but that the heat-labile NCA and ECA are dependent on mast cells for their production by a different cell, tentatively identified as the macrophage.     

Tryptase levels as an indicator of mast-cell activation in systemic anaphylaxis and mastocytosis

Better methods are needed to assess mast-cell activation in vivo and to distinguish the activation of mast cells from that of basophils. Tryptase, a neutral protease selectively concentrated in the secretory granules of human mast cells (but not basophils), is released by mast cells together with histamine and serves as a marker of mast-cell activation. In 17 patients with systemic mastocytosis, concentrations of tryptase in plasma were linearly related to those of histamine (P less than 0.01). Eleven of the 17 patients had tryptase levels of 4 to 88 ng per milliliter, indicating ongoing mast-cell activation. In each of six patients who experienced corresponding anaphylactic reactions after penicillin, aspirin, or melon ingestion, a wasp sting, exercise, or antilymphocyte globulin injection, tryptase levels in serum ranged from 9 to 75 ng per milliliter, indicating mast-cell activation during each of these events. In contrast, serum tryptase levels were less than 5 ng per milliliter in all patients presenting with myocardial disease (n = 8, 6 with hypotension) or sepsis (n = 6, 3 with hypotension) and in the controls (n = 20). One patient had a myocardial infarction after anaphylaxis in response to a wasp sting and an elevated tryptase level of 25 ng per milliliter. Thus, the plasma or serum tryptase level is a diagnostic correlate of mast-cell-related events.     

Diagnostic value of tryptase in anaphylaxis and mastocytosis

Serum (or plasma) levels of total and mature tryptase measurements are recommended in the diagnostic evaluation of systemic anaphylaxis and systemic mastocytosis, but their interpretation must be considered in the context of a complete workup of each patient. Total tryptase levels generally reflect the increased burden of mast cells in patients with all forms of systemic mastocytosis (indolent systemic mastocytosis, smoldering systemic mastocytosis, systemic mastocytosis associated with a hematologic clonal non-mast cell disorder, aggressive systemic mastocytosis, and mast cell leukemia) and the decreased burden of mast cells associated with cytoreductive therapies in these disorders. Causes of an elevated total tryptase level other than systemic mastocytosis must be considered, however, and include systemic anaphylaxis, acute myelocytic leukemia, various myelodysplastic syndromes, hypereosinophilic syndrome associated with the FLP1L1-PDGFRA mutation, end-stage renal failure, and treatment of onchocerciasis. Mature (beta) tryptase levels generally reflect the magnitude of mast cell activation and are elevated during most cases of systemic anaphylaxis, particularly with parenteral exposure to the inciting agent.     

人肥大细胞的IgE依赖性组胺和类胰蛋白酶分泌

目的　利用人结肠组织的肥大细胞和肥大细胞激活的体外研究系统评价人肥大细胞释放类胰蛋白酶和组胺的能力及其机制。方法　经酶悬浮的人结肠肥大细胞与抗IgE抗体共同培养后记录浓度相关曲线和时间关系曲线。类胰蛋白酶用酶联免疫吸附试验的方法测量 ,而组胺则由一种以玻璃纤维为基础的荧光比色法测量。结果　抗IgE抗体可引起浓度相关性的组胺和类胰蛋白酶释放 ,最大组胺和类胰蛋白酶分泌量分别比基础分泌量超出 2 .7和 2 .5倍以上。抗IgE抗体的作用从加样后 10s开始 ,6min后达高峰并至少持续 15min。百日咳毒素和代谢抑制剂能够分别抑制抗IgE抗体引起的组胺和类胰蛋白酶释放。百日咳毒素还能够减少自发性类胰蛋白酶释放。结论　人结肠肥大细胞在受到抗IgE抗体刺激时具有平行释放类胰蛋白酶和组胺的能力 ,这个过程与肥大细胞膜G蛋白偶联受体的激活有关 ,并消耗能量。肥大细胞自发性释放组胺和类胰蛋白酶的功能可能是通过不同的机制实现的。     

Inhibition of tryptase release from human colon mast cells by histamine receptor antagonists

The main objective of this study was to investigate the ability of histamine receptor antagonists to modulate tryptase release from human colon mast cells induced by histamine. Enzymatically dispersed cells from human colon were challenged with histamine in the absence or presence of the histamine receptor antagonists, and the tryptase release was determined. It was found that histamine induced tryptase release from colon mast cells was inhibited by up to approximately 61.5% and 24% by the H1 histamine receptor antagonist terfenadine and the H2 histamine receptor antagonist cimetidine, respectively, when histamine and its antagonists were added to cells at the same time. The H3 histamine receptor antagonist clobenpropit had no effect on histamine induced tryptase release from colon mast cells at all concentrations tested. Preincubation of terfenadine, cimetidine or clobenpropit with cells for 20 minutes before challenging with histamine did not enhance the ability of these antihistamines to inhibit histamine induced tryptase release. Apart from terfenadine at 100 microg/ml, the antagonists themselves did not stimulate tryptase release from colon mast cells following both 15 minutes and 35 minutes incubation periods. It was concluded that H1 and H2 histamine receptor antagonists were able to inhibit histamine induced tryptase release from colon mast cells. This not only added some new data to our hypothesis of self-amplification mechanisms of mast cell degranulation, but also suggested that combining these two types of antihistamine drugs could be useful for the treatment of inflammatory bowel disease (IBD).     

Long-term follow-up of histamine turnover in mastocytosis

To study the long-term histamine turnover in patients with mastocytosis, the urinary excretion of the main histamine metabolite tele-methylimidazoleacetic acid was measured. Eighteen patients, 10 with urticaria pigmentosa and 8 with systemic mastocytosis, were followed for several years (mean 4.2 years). Younger individuals (less than 30 years) had initially normal excretion or tended to normalize their excretion during follow-up, while older patients (greater than 30 years) often had systemic manifestations and higher excretion values, which increased in some cases during the observation period.     

Mastocytosis and allergy

PURPOSE OF REVIEW: To illustrate features of allergy in mastocytosis. RECENT FINDINGS: The rates of atopy in patients with mastocytosis have generally been found to be similar to those of the normal population, although the incidence of anaphylaxis is much higher in mastocytosis. Introduction of objective pathologic criteria by the WHO for the diagnosis of mastocytosis has greatly facilitated the workup of patients with suspected mastocytosis, and has led to identification of mast cell disease in a subset of patients with anaphylaxis. There is increasing evidence that an activating c-kit mutation (D816V) exists in a subset of patients with recurrent mast cell activation symptoms who have normal-appearing bone marrow biopsies in routine evaluations without skin lesions. The genetic deficiency of alpha tryptase has not been found to influence serum tryptase levels in patients with mastocytosis. SUMMARY: Pathologic mast cell activation is a key finding in both allergic diseases and mastocytosis, albeit caused by entirely different mechanisms. Mastocytosis should be suspected in patients with recurrent anaphylaxis, who present with syncopal or near-syncopal episodes without associated hives or angioedema.     

Are gastrointestinal mucosal mast cells increased in patients with systemic mastocytosis?

In patients with mastocytosis, gastrointestinal symptoms are a frequent phenomenon. However, there are only limited data about the quantity and distribution pattern of mast cells in the gastrointestinal mucosa. We stained gastroduodenal biopsy specimens from 27 patients with mastocytosis and 48 control subjects for mast cell tryptase, CD117, and CD25. The numbers of mucosal mast cells per high-power field showed wide variation in all groups and were decreased markedly in biopsy specimens of corpus and duodenum and statistically significantly decreased in antrum biopsy specimens from patients with systemic mastocytosis compared with patients with pure urticaria pigmentosa and with control subjects. Staining for tryptase showed highly significant correlation with staining for CD117. All mast cells were negative for CD25, which is expressed characteristically by neoplastic mast cells. Causes of the decrease of mucosal mast cells remain enigmatic, but our results show that gastrointestinal symptoms of patients with mastocytosis are most likely mediator-related and not due to an increase of local mast cells.     

The anaphylaxis hypothesis of sudden infant death syndrome (SIDS): mast cell degranulation in cot death revealed by elevated concentrations of tryptase in serum

A series of cases of sudden unexpected post-neonatal deaths from two centres in the UK have been investigated for evidence of mast cell activation using the biochemical markers tryptase and 9α,11β-PGF₂. Tryptase was selected as a possible marker because it is a component of mast cell secretory granules and, unlike histamine, it is not released from basophils. The prostaglandin 9α,11β-PGF₂ is an initial and pharmacologically active metabolite of PGD₂, the major mast cell-derived cyclo-oxygenase product. This prostaglandin was chosen to serve as a marker of newly generated mediator release. In the study, unexplained infant deaths were associated with a higher concentration of tryptase in serum compared with cases of unexpected, but subsequently explained death. However, 9α,11β-PGF₂ was found to be an unsuitable post mortem marker in this situation. These results provide direct evidence that mast cell degranulation, possibly as a result of anaphylaxis, may be occurring around the time of death in some cases of cot death.     

Effects of fexofenadine on the early response to nasal allergen challenge.

BACKGROUND: Previous studies using nasal allergen challenge models have shown that terfenadine, an H1 antihistamine, inhibits histamine release during the early response to allergen provocation. Fexofenadine, the active metabolite of terfenadine, has strong H1-antihistaminic activity and no cardiac effects. Clinical studies have documented the efficacy of fexofenadine in the treatment of allergic rhinitis. OBJECTIVE: To determine whether fexofenadine, like terfenadine, inhibits histamine and tryptase release during the early allergic response. METHODS: Randomized, double blind, placebo-controlled, two-way crossover study in 20 subjects with seasonal allergic rhinitis, out of their allergy season (median age 27.5 years, 13 males and 7 females). Subjects were medicated with either placebo or fexofenadine 180 mg orally daily for 1 week followed by nasal challenge with allergen. After each challenge, sneezes and nasal symptoms were recorded, and a nasal lavage was obtained for the assay of albumin, an indicator of vascular permeability, and histamine and tryptase, indicators of mast cell degranulation. RESULTS: When patients were on placebo, allergen challenges led to significant increases in all measured parameters compared with the sham challenges with diluent. Treatment with fexofenadine resulted in inhibition of allergen-induced symptoms and increased vascular permeability, but not the release of histamine and tryptase. CONCLUSION: Fexofenadine is an effective H1 antihistamine, but in contrast to its parent compound, terfenadine, it does not affect the release of the mast cell mediators histamine and tryptase.     

Modulation of tryptase and histamine release from human lung mast cells by protease inhibitors

Inhibition of IgE dependent histamine release from human mast cells by protease inhibitors has been observed in skin, tonsil and synovial tissues. However, little is known about the actions of protease inhibitors on tryptase release from human lung mast cells. We therefore examined the ability of protease inhibitors to modulate tryptase and histamine release from human lung mast cells. IgE dependent tryptase release from dispersed lung mast cells was inhibited to a maximum of approximately 53.8% and 44.5% by N-a-tosyl-L-lysine chloromethyl ketone (TLCK) and N-p-Tosyl-L-phenylalanine chloromethyl ketone (TPCK), respectively. A similar degree of inhibition of calcium ionophore A23187 (CI) induced tryptase release was also observed with these two inhibitors. Preincubation of TLCK or TPCK with the mast cells at 37 degrees C for 20 minutes before addition of anti-IgE or CI did not improve their ability to inhibit anti-IgE and CI induced tryptase release. At a concentration of 10 microg/ml, protamine inhibited anti-IgE or CI induced tryptase release; but at 100 microg/ml, it increased anti-IgE and CI induced release of tryptase from lung mast cells. A concentration dependent inhibition of anti-IgE and CI induced release of histamine from lung mast cells was also observed with TLCK, TPCK and protamine. The maximum inhibition of anti-IgE induced histamine release was approximately 40.7%, 40.2% and 33.4% with TLCK, TPCK and protamine, respectively. At the concentrations tested, TLCK and TPCK by themselves did not stimulate tryptase and histamine release from lung mast cells. A specific inhibitor of aminopeptidase, amastatin, had no effect on anti-IgE induced tryptase and histamine release and was used as control. In conclusion, it was demonstrated that protease inhibitors are able to inhibit IgE dependent tryptase and histamine release from human lung mast cells, which suggested that they could be developed to a novel class of anti-inflammatory drugs to treat allergic conditions in man.     

Mast cell mediators in allergic inflammation and mastocytosis

Mast cells possess an array of potent inflammatory mediators capable of inducing acute symptoms after cell activation, including urticaria, angioedema, bronchoconstriction, diarrhea, vomiting, hypotension, cardiovascular collapse, and death in few minutes. In contrast, mast cells can provide an array of beneficial mediators in the setting of acute infections, cardiovascular diseases, and cancer. The balance between the detrimental and beneficial roles of mast cells is not completely understood. Although the symptoms of acute mast cell mediator release can be reversed with epinephrine, adrenergic agonists, and mediator blockers, the continued release of histamine, proteases, prostaglandins, leukotrienes, cytokines, and chemokines leads to chronic and debilitating disease, such as mastocytosis. Identification of the molecular factors and mechanisms that control the synthesis and release of mast cell mediators should benefit all patients with mast cell activation syndromes and mastocytosis.     

Diagnostic and subdiagnostic accumulation of mast cells in the bone marrow of patients with anaphylaxis: Monoclonal mast cell activation syndrome

BACKGROUND: Patients with mastocytosis may suffer from severe hypotension after wasp or bee stings. In these patients, no specific IgE is detectable, but they usually have skin lesions and an elevated serum tryptase level. METHODS: We report on 6 patients who were referred to our department because of severe hypotension following bee or wasp stings without cutaneous lesions. RESULTS: In 3 patients, the baseline serum tryptase level was elevated (26, 36, and 67 ng/ml, respectively), and investigation of their bone marrow revealed systemic mastocytosis (SM). In the remaining 3 patients, serum tryptase levels were <20 ng/ml, and bone marrow histology and tryptase immunohistochemistry did not reveal diagnostic mast cell infiltrates. However, in 1 patient, three minor SM criteria were demonstrable leading to the diagnosis SM, and in the 2nd patient, two minor SM criteria, including an aberrant mast cell phenotype, were found. In the 3rd patient, no minor SM criteria were detected. CONCLUSIONS: All patients with unexplained hypotension after hymenoptera stings should undergo a thorough investigation for major and minor SM criteria regardless of the tryptase level or presence of skin lesions, in order to diagnose or exclude SM or a related subdiagnostic condition (1 or 2 minor SM criteria) tentatively termed monoclonal mast cell activation syndrome.     

Autoimmune type I reactions directed against nuclear components in rheumatoid arthritis

Basophil histamine release was examined in leucocyte suspensions from patients with rheumatoid arthritis (RA) after challenge of the cells with isolated and sonicated leucocyte nuclei from normal individuals. Most of the patients with active disease responded with significant histamine release, whereas no response was obtained in the inactive patients and in normal controls. A similar pattern was found in the urinary excretion of the main metabolite of histamine, NT-methyl-imidazoleacetic acid, since an increased excretion was observed in most patients with severe disease activity in contrast to patients with moderate and quiescent activity and the control group. These findings strongly indicate an involvement of autoimmune allergic type I reactions in RA. The release of histamine and other mediators from basophils and mast cells may cooperate in the inflammatory reactions and the destruction of the joints in RA.     

Mastocytosis and Hymenoptera venom allergy

PURPOSE OF REVIEW: Mastocytosis is a rare disease characterized by increased mast cells in skin and/or internal organs. We evaluate the impact of mastocytosis on diagnosis and treatment of Hymenoptera venom allergy. RECENT FINDINGS: Patients with Hymenoptera venom allergy who suffer from mastocytosis develop life-threatening sting reactions more often than those who do not. When patients with Hymenoptera venom allergy were systematically examined for mastocytosis, it was found to be represented to an abnormally high extent. Most patients with mastocytosis tolerate venom immunotherapy with no or only minor systemic symptoms. Venom immunotherapy was found to be marginally less effective in patients with mastocytosis than in those without evidence of mast cell disease (defined as absent cutaneous mastocytosis combined with a serum tryptase concentration of <11.4 microg/l). Several deaths from sting reactions were reported in patients with mastocytosis after venom immunotherapy was stopped. These patients should have venom immunotherapy for the rest of their lives. SUMMARY: Patients suffering from mastocytosis and Hymenoptera venom allergy are at risk from a particularly severe sting anaphylaxis. They need optimal diagnosis and treatment. In patients presenting with Hymenoptera venom allergy, screening tests by measurement of serum tryptase concentration, and a careful skin examination, are highly recommended.     

IgG-mediated histamine release from canine mastocytoma-derived cells

BACKGROUND: Recent data suggest that normal tissue mast cells can express functional receptors for IgG under certain conditions. However, little is known about IgG receptor expression and functional consequences in mast cell neoplasms. METHODS: In this study, neoplastic mast cells were obtained from a dog with cutaneous mastocytoma (CM-MC) and from a dog with visceral mastocytoma (VI-MC). Both cell populations were characterized morphologically and functionally. RESULTS: Most cells proliferated constantly in suspension without particular supplements. Doubling times of CM-MC and VI-MC were 52.2 and 27.5 h, respectively. Both cell types were sensitive to formalin fixation, did not contain heparin and were tryptase and chymase positive. Electron microscopy showed fine granules with electron-dense content in both cell populations. The total histamine content of CM-MC and VI-MC was 0.25 and 0.10 pg/cell, respectively. Calcium ionophore A23187 and substance P induced dose-dependent histamine release, whereas compound 48/80 had no effect. Most significantly, both cell types, when sensitized with monomeric dog IgG, released histamine upon stimulation by anti-dog IgG. CONCLUSIONS: Dog mastocytoma-derived cells may be useful to study the regulation of neoplastic mast cell growth and differentiation, as well as IgG receptor-mediated activation in neoplastic mast cells. Further research is required to clarify the pathophysiological significance of constitutive expression of IgG receptors in neoplastic (canine) mast cells.     

Azelastine is more potent than olopatadine n inhibiting interleukin-6 and tryptase release from human umbilical cord blood-derived cultured mast cells.

BACKGROUND: Mast cells are involved in early- and late-phase reactions by releasing vasoactive molecules, proteases, and cytokines. Certain histamine-1 receptor antagonists and other antiallergic drugs seem to inhibit the release of mediators from rat and human mast cells. OBJECTIVE: Azelastine and olopatadine are antiallergic agents present in the ophthalmic solutions azelastine hydrochloride (Optivar, Asta Medica/Muro Pharmaceuticals, Tewksbury, MA), and olopatadine hydrochloride (Patanol, Alcon Laboratories, Fort Worth, TX), respectively. We investigated the effect of these drugs on interleukin-6 (IL-6), tryptase, and histamine release from cultured human mast cells (CHMCs). METHODS: CHMCs were grown from human umbilical cord blood-derived CD34+ cells in the presence of stem cell factor and IL-6 for 14 to 16 weeks. Sensitized CHMCs were pretreated with various concentrations of azelastine or olopatadine for 5 minutes. CHMCs were then challenged with anti-immunoglobulin E, and the released mediators were quantitated. RESULTS: The greatest inhibition of mediator release was seen with 24 microM azelastine; this level of inhibition was matched with the use of 133 microM olopatadine. At this concentration, these drugs inhibited IL-6 release by 83% and 74%, tryptase release by 55% and 79%, and histamine release by 41% and 45%, respectively. Activated CHMCs were characterized by numerous filopodia that were inhibited by both drugs as shown by electron microscopy. CONCLUSIONS: These results indicate that azelastine and olopatadine can inhibit CHMCs activation and release of IL-6, tryptase, and histamine. On an equimolar basis, azelastine was a more potent inhibitor than olopatadine.     

Characteristics of histamine release from cultured human mast cells

Background The mtist cell is one of the important cells In the pathogenesis of allergic disorders. However, isolating human mast cells is a laborious procedure. Recently, cultured human mast cells raised from umbilical cord blood cells have become available. It is necessary to examine whether these cells are useful in investigating the role of mast cells in human diseases. Objective The phenotype of mast cells depends on their anatomical sites. To examine which phetiotype of mast cells these cultured mast cells most closely resemble, their ability to release was investigated. Methods The mast cells were raised from human umbilical cord blood cells in the presence of stem cell factor and interIeukin-6. To determine the mast cell subtypes, the mast cells were immunocytochemically stained for tryptase and chymase. The cultured mast cells were then stimulated with various secretagogues, and histamine release was measured by a fluorometric technique using high-performance liquid chromatography. Results The immunocytochemical staining for mast cell proteases revealed that virtually all cells contained tryptase, the definitive marker of mast cells, and that about a quarter of the cells contained chymase. Anti-TgE effectively stimulated these mast cells to release histamine in a dose-dependent, lime-dependent manner. The release was completed in about 30 min. One of the non-specific stimuli, calcium ionophore A23I87. also induced histamine release in a dose-dependent, time-dependent manner. In contrast, compound 48/80 and substance P failed to induce histamine release from these cells. Conclusion Cultured human mast cells resemble lung mast cells in their ability to release histamine. They will help in studying the functional properties of human mast cells and may contribute to clarifying the pathophysiology of human allergic diseases.     

Recent advances in mastocytosis research. Summary of the Vienna Mastocytosis Meeting 1998.

The term mastocytosis denotes a heterogenous group of disorders characterized by abnormal growth and accumulation of mast cells in one or more organs. Cutaneous and systemic variants of the disease have been described. Mast cell disorders have also been categorized according to other aspects, such as family history, age, course of disease, or presence of a concomitant myeloid neoplasm. However, so far, generally accepted disease criteria are missing. Recently, a number of diagnostic (disease-related) markers have been identified in mastocytosis research. These include the mast cell enzyme tryptase, CD2, and mast cell growth factor receptor c-kit (CD117). Several gain-of-function-mutations in the kinase domain of c-kit appear to occur in mastocytosis supporting the clonal (neoplastic) nature of the disease. Also, certain point mutations appear to be associated with distinct variants of mastocytosis, i.e. Asp-816-->Val with a subset of sporadic persistent (systemic) mastocytosis (mostly adults), and Gly-839-->Lys with (a subset of) typical pediatric (mostly cutaneous) mastocytosis. Another potential indicator of mast cell neoplasm is the T-/NK-cell-associated marker CD2. This antigen (LFA-2) is abnormally expressed on neoplastic mast cells in cases of systemic mastocytosis or mast cell leukemia, but not found on normal mast cells. The mast cell enzyme tryptase is increasingly used as a serum- and immunohistochemical marker to estimate the actual spread of disease (burden of neoplastic mast cells). The clinical significance of novel mastocytosis markers is currently under investigation. First results indicate that they may be useful to define reliable criteria for the delineation of the disease.