The mast cell and mast cell disease

Bone graft and implants in a patient with systemic mastocytosis

BACKGROUND

Systemic mastocytosis (mast-cell proliferation in various organs, including the skeleton) is a rare disease. Reports on mastocytosis that affects facial bones are few. The bone lesions may be osteolytic or sclerotic.

PURPOSE

To describe (for the first time) bone grafting followed by dental implant treatment yielding a good result in a patient with systemic mastocytosis.

MATERIALS AND METHODS

A bone graft was performed on a 60-year-old woman with systemic mastocytosis. Dental implant treatment was performed 13 weeks after sclerotic bone of the iliac crest was grafted to the maxillary sinus bilaterally. A microimplant was installed simultaneously with the dental implants and was removed 6 months later for histomorphometric evaluation. Bone biopsy specimens from the donor site of the sclerotic iliac crest and later from the remodeled maxillary bone graft were histologically analyzed. A clinical examination of the patient with regard to her mastocytosis was performed by a dermatologist. The patient was followed up after 3 years.

RESULTS

Bone grafting and dental implant treatment were successful, and the patient's clinical and radiologic situation was stable after 3 years. Histologic examination of the bone grafted from the iliac crest showed sclerotic lesions in the bone and a dense infiltration of mast cells. The bone graft seemed to remodel initially in a normal way in the maxillary sinus. However, computed tomography 3 years later showed regions of sclerosis in the remodeled maxillary bone. These lesions now had a pattern similar to the adjacent facial bone. Both the microimplant and the dental implants integrated well. Bone-implant contact measured on the microimplants was 20% higher in this actual case, compared to that of patients previously treated and grafted with the same technique.

CONCLUSIONS

There are many clinical implications to be considered when treating this group of patients. Bone grafting, remodeling of the bone, and dental implant installation were successful in this patient with systemic mastocytosis and signs of osteosclerosis. Installation of microimplants in patients with pathologic bone conditions may allow successful dental implant treatment.

Prehepatic portal hypertension produces increased mast cell density in the small bowel and in mesenteric lymph nodes in the rat

BACKGROUND

Because most of the characteristics of the portal hypertensive enteropathy can be explained on the basis of increased levels of mast cell mediators, the purpose of the present paper was to study mast cell splanchnic infiltration.

METHODS

Duodenum, jejunum, ileum and mesenteric lymph node complex infiltration by mast cells was assayed by a stereological technique in control rats (group I; n = 5) and in an experimental model of portal hypertension (the portal vein-stenosed rat, group II; n = 5) at 6 weeks after operation.

RESULTS

Intestinal and mesenteric lymph node complex infiltration by mast cells increased in the animals with partial portal vein ligation. The mast cell density progressively increased distally along the small bowel. The mast cell increase in the mesenteric lymph node complex in portal vein-stenosed rats was greater than in the duodenum (P = 0.001), jejunum (P = 0.006) and ileum.

CONCLUSION

The rise of mast cells density in the small bowel and mesenteric lymph node complex in rats with partial portal vein ligation suggests that these cells are involved in the etiopathogenesis of experimental portal prehepatic hypertensive enteropathy.

Combined Mastocytoma-Junctional Nevus

A unique combined mastocytoma-junctional nevus presented as a 4-mm dark brown macule in the axilla of a 57-year-old white female. Histopathologic examination revealed a proliferation of mast cells partially or completely filling the dermal papillae, hyperpigmentation of the basal keratinocytes and mildly increased basal melanocytes. Overlying the mast cell proliferation, pigmented junctional nevus nests were present. The mast cells were strongly positive with Giemsa stain and mast cell tryptase immunohistochemical stain; nevomelanocytic cells were negative. Nevomelanocytes were strongly immunoreactive for S100, HMB-45, Mart-1, and tyrosinase; mast cells were negative. The clinicopathologic features suggested a synchronous proliferation of 2 cell types in the same small cutaneous field rather than a collision tumor. While the cutaneous mast cells probably originated as a disseminated clone, it is postulated that local mast cell growth factor induced nevomelanocytic proliferation and modulated mast cell growth. In fact, the tumor exhibited strong immunoreactivity for the mast cell growth factor receptor (CD117) in mast cells, basal melanocytes, and nevus nests. The incidence of dual mast cell-melanocytic tumors appears to be very low, as only 3 total cases have now been reported. However, since in patients with multiple mastocytomas only a small fraction of lesions are biopsied, the true incidence may be higher than supposed.

Cutaneous mastocytosis in children: a clinical analysis of 71 cases

OBJECTIVE

To characterize the clinical features, response to therapy, evolution and prognosis of cutaneous mastocytosis in children.

BACKGROUND

Mastocytosis in children, instead of being induced by a potentially oncogenic c-kit mutation, is probably a clonal disease with benign prognosis.

METHODS

The clinicopathological features, evolution and response to treatment were analysed in 71 children with mastocytosis.

RESULTS

There were 53 (75%) cases of urticaria pigmentosa, 12 (17%) cases of mastocytoma, and six (8%) cases of diffuse cutaneous mastocytosis. In 92% of cases disease onset was in the first year of life. There was a male predominance 1.8 : 1. Treatment did not modify the disease evolution. Eighty per cent of patients improved or had spontaneous resolution of the disease.

CONCLUSION

The most frequent clinical form of mastocytosis was urticaria pigmentosa followed by mastocytoma and diffuse cutaneous mastocytosis. Darier's sign was present in 94% of cases. A negative Darier's sign does not rule out mastocytosis. In contrast to adults, mastocytosis in children usually has a benign course making sophisticated or invasive diagnostic tests unnecessary. A classification of paediatric cutaneous mastocytosis is proposed.

The vesicular monoamine transporter 2 (VMAT2) is expressed by normal and tumor cutaneous mast cells and Langerhans cells of the skin but is absent from Langerhans cell histiocytosis

Monoamine storage in secretory granules is mediated by the vesicular monoamine transporters 1 and 2 (VMAT1 and VMAT2). The aim of our study was to identify monoamine-handling normal and neoplastic inflammatory cells in the skin by their expression of VMAT1 and VMAT2. Normal skin from various parts of the body, as well as 21 cases of cutaneous mastocytosis and 10 cases of cutaneous Langerhans cell histiocytosis were analyzed by immunohistochemistry, radioactive in situ hybridization, and double-fluorescence confocal microscopy. VMAT2-positive cells in the subepidermal layer were identified as mast cells by their expression of tryptase. Neoplastic mast cells in all cases of cutaneous mastocytosis retained their VMAT2 positivity. The intraepidermal VMAT2-expressing cells were identified as Langerhans cells by their CD1a positivity. VMAT2 was absent from Langerhans cell histiocytosis. VMAT2 is an excellent marker for normal and neoplastic mast cells. The expression of VMAT2 demonstrates the capacity of mast cells for monoamine storage and handling. The presence of VMAT2 in epidermal Langerhans cells revealed a previously unrecognized monoamine-handling phenotype of these cells and indicates possible involvement of amine storage and release associated with antigen presentation. Absence of VMAT2 in neoplastic Langerhans cells indicates a loss of monoamine handling capacity of these cells during tumorigenesis.

Urticaria pigmentosa

Urticaria pigmentosa (UP), resulting from the accumulation of excessive numbers of mast cells in the skin, is the most common form of cutaneous mastocytosis. Observations highlight the diversity of this disease. Clonal expansion of early hematopoietic progenitor cells carrying activating mutations in KIT seems to be the basis of adult-onset UP. New pathogenetic findings are leading to the development of new diagnostic surrogate markers of disease and therapeutic approaches targeting neoplastic mast cells. Promising strategies may arise from an increased understanding about the cause of mastocytosis and the signaling pathways initiated by kit activation.

Flavones inhibit proliferation and increase mediator content in human leukemic mast cells (HMC-1)

OBJECTIVE

Mast cells are involved in allergic and inflammatory reactions. These cells are also increased in the bone marrow, skin, and other organs in systemic mastocytosis. Flavonoids are naturally occurring molecules with antioxidant, cytoprotective, and anti-inflammatory activities. Some flavonoids, like quercetin, inhibit the growth of certain malignant cells in culture. Quercetin also inhibits histamine release and induces accumulation of secretory granules in rat basophilic leukemia cells.

METHOD

We investigated the effect of five flavonoids: flavone, kaempferol, morin, myricetin, and quercetin at 1, 10, and 100 microM on proliferation and secretory mediator content (beta-hexosaminidase, histamine, and tryptase) in human leukemic mast cells (HMC-1), the doubling time of which was about 2 d.

RESULTS

Flavone and kaempferol at 100 microM inhibited cell proliferation over 80% on either day 3, 4, or 5 of culture. Quercetin showed this level of inhibition only on day 5, myricetin inhibited by 50% at days 3-5, whereas morin's inhibition was < 20%. All flavonoids (except morin) at 100 microm increased histamine and tryptase content, but not beta-hexosaminidase, equally at days 3 and 4 of culture quercetin also increased the development of secretory granules.

CONCLUSION

These results indicate that certain flavonoids can inhibit HMC-1 proliferation, induce secretory granule development and the accumulation of mediators.

Indolent systemic mast cell disease: immunophenotypic characterization of bone marrow mast cells by flow cytometry

BACKGROUND

Mast cell disease has a low prevalence and is difficult to diagnose in the absence of the characteristic skin lesions that usually accompany the condition. Extracutaneous involvement is not easy to assess. There are reports in the recent literature on the use of tryptase as a reliable immunohistochemical marker as well as on the study of the immunophenotype of bone marrow mast cells. The latter is of great help for the diagnosis of systemic involvement as, after the skin, the bone marrow is the organ most commonly affected by the disease.

OBJECTIVE

We describe two cases of indolent systemic mast cell disease (SMCD) where flow cytometry was used to identify immunophenotypical characteristics of bone marrow mast cells. Recent advances in the application of this technique prove it can be a good diagnostic tool for assessing systemic involvement of the disease.

PATIENTS AND METHODS

Two adult subjects with indolent SMCD had multiple clinical symptoms. Cutaneous lesions were the clue to the diagnosis but, subsequently, in the presence of disturbing symptoms, involvement of other organ systems was confirmed. In both cases, the authors used flow cytometry techniques, as described by Escribano et al. (1998) to define the immunophenotype of bone marrow mast cells.

RESULTS

Both patients were diagnosed with indolent SMCD with cutaneous and bone marrow involvement. Also, they presented visible clues to the presumptive bone, cardiovascular and nervous system involvement. Gastrointestinal manifestations were documented in one case.

CONCLUSIONS

The use of flow cytometry on bone marrow samples from patients with mastocytosis reveals immunophenotypic differences that can serve to allow classification of these subjects in the category of indolent SMCD even though involvement of another organ system may not be thoroughly confirmed.

Effect of tyrosine kinase inhibitor STI571 on the kinase activity of wild-type and various mutated c-kit receptors found in mast cell neoplasms

Systemic mastocytosis (SM) is a rare disease caused by an abnormal mast cell accumulation in various tissues. Two classes of constitutive activating c-kit mutations are found in SM. The most frequent class occurs in the catalytic pocket coding region with substitutions at codon 816 and the other in the intracellular juxtamembrane coding region. Therefore, kinase inhibitors that block mutated c-kit activity might be used as therapeutic agents in SM. Here, we show that STI571 inhibits both wild-type and juxtamembrane mutant c-kit kinase activity, but has no effect on the activity of the D816 V mutant. Accordingly, STI571 selectively decreases the survival of normal mast cell and of mast cell lines either with juxtamembrane c-kit mutations, but not that of tumoral mast cell from patient with SM or of mast cell lines with the D816 V mutation. Therefore, STI571 is not a good candidate to treat SM and specific kinase inhibitors should be designed to inhibit constitutive activating mutations at codon 816.

Treatment of adult systemic mastocytosis with interferon-alpha: results of a multicentre phase II trial on 20 patients

Systemic mastocytosis (SM) is characterized by proliferation of mast cells in various organs, which may release a wide variety of mediators, thereby explaining the broad clinical spectrum of disease manifestations. The potentially life-threatening systemic symptoms and tumoral proliferation are poorly controlled despite the use of several cytotoxic chemotherapies and/or symptomatic treatments. Twenty consecutive adult SM patients with histologically confirmed bone marrow (BM) involvement received interferon-alpha subcutaneously (1-5 million units/m2/d, with progressive dose intensification over the first month of treatment) and were evaluated after 6 months of therapy. Seven of them had previously received symptomatic treatments, including steroids, which were ineffective. Among the 13 patients treated for at least 6 months, seven partial and six minor responses, mainly concerning vascular congestion and skin lesions, were obtained, while BM infiltration remained unchanged in 12 patients. The significant reduction of mast-cell mediator levels after 6 months of treatment was not predictive of clinical remission. The rate of depression was unexpectedly high (seven patients; 35%). Two patients died soon after starting therapy (one myocardial infarction, one septic shock). Six months of interferon-alpha may relieve vascular congestion in adults with SM, probably by inhibiting mast-cell degranulation.

Pruritus in systemic disease: mechanisms and management

Pruritus is the most common symptom of skin disease. Even in the absence of primary cutaneous findings, severe and extensive pruritus often is associated with systemic disease. This review considers briefly the physiology of pruritus and discusses the various systemic diseases often accompanied by this bothersome symptom. In addition to exploring the possible mechanisms and potential therapies of itching in selected disorders, this review presents general recommendations for evaluating patients with unexplained pruritus and management guidelines for alleviating their discomfort.

Comparison of mastocytosis with onset in children and adults

OBJECTIVE

To compare the incidence, symptomatology and course of mastocytosis with onset in childhood and in adults.

DESIGN

Retrospective study of 101 patients with mastocytosis who were referred from 1980 to 1998.

PATIENTS

Medical records of 65 cases of mastocytosis with onset in childhood and 36 in adulthood were analysed. The clinical course was assessed in a subgroup consisting of 33 subjects with childhood onset who were followed up until at least adolescence and 12 subjects with adult onset who were followed up for at least 10 years.

RESULTS

The onset of the disease occurred before the age of 2 years in 50% and between the ages of 2 and 15 years in 14% of cases (childhood onset). In 36% of patients onset occurred at the age of 16 years and older (adult onset). An incidence peak of 60% was noted in the first year of life. Mast cell-mediated symptoms were not experienced by 21 of 36 adult onset mastocytosis patients nor by 27 of 65 childhood onset mastocytosis patients. Complete resolution was observed in five of 33 children. The majority of childhood onset cases (21 of 33) showed some improvement. Complete resolution was achieved in three of 12 adults. The majority of the remaining adults (eight of 12) showed no improvement.

CONCLUSIONS

We confirm the incidence of onset of mastocytosis previously reported in the literature. We conclude that childhood onset mastocytosis is much less transitory than generally is assumed, although improvement occurs in the majority of cases. Symptomatology and clinical course of adult onset mastocytosis is less severe than suggested in the literature.

Atypical cellular disorders

Atypical cellular disorders are commonly considered part of the gray zone linking oncology to hematology and immunology. Although these disorders are relatively uncommon, they often represent significant clinical problems, provide an opportunity to understand basic disease mechanisms, and serve as model systems for the development of novel targeted therapies. This chapter focuses on such disorders. In Section I, Dr. Arceci discusses the pathogenesis of Langerhans cell histiocytosis (LCH) in terms of the hypothesis that this disorder represents an atypical myeloproliferative syndrome. The clinical manifestations and treatment of LCH in children and adults is discussed along with possible future therapeutic approaches based upon biological considerations. In Section II, Dr. Longley considers the molecular changes in the c-Kit receptor that form the basis of mastocytosis. Based on the location and function of c-Kit mutations, he develops a paradigm for the development of specific, targeted therapies. In Section III, Dr. Emanuel provides a review of the "mixed myeloproliferative and myelodysplastic disorders," including novel therapeutic approaches based on aberrant pathogenetic mechanisms. Taken together, these chapters should provide an overview of the biological basis for these disorders, their clinical manifestations, and new therapeutic approaches.

Neuro-immune-endocrine functional system and vascular pathology

A new interpretation of the response to injury by the nervous, immune and endocrine system is proposed, in order to integrate biochemical knowledge into the respective clinical areas. The discovery that the signaling molecules of the classical nervous, immune and endocrine systems, that is, the neurotransmitters, cytokines and hormones, respectively, are expressed and perceived by the three systems, has enabled us to establish a functional concept of these systems. The hypothetical integration of different pathological processes in a functional response made up by three phases, the immediate or nervous, intermediate or immune and late or endocrine ones, makes it possible to consider that all of them represent different forms of expression of a functional response whose meaning is always the same, that is, inflammation. If the functions that characterize each one of these three phases represent the activity of the nervous, immune and endocrine systems, the biochemical knowledge could be integrated into the functional meaning of each system.

Apoptosis-inducing human-origin Fcepsilon-Bak chimeric proteins for targeted elimination of mast cells and basophils: a new approach for allergy treatment

During the past few years, many chimeric proteins have been developed to specifically target and kill cells expressing specific surface molecules. Generally these molecules carry a bacterial or plant toxin to destroy the unwanted cells. The major obstacle regarding these molecules in their clinical application is the immunogenicity and nonspecific toxicity associated with bacterial or plant toxins. We lately reported a new approach for construction of chimeric proteins: we successfully replaced bacterial or plant toxins with human apoptosis-inducing proteins. The resulting chimeras were shown to specifically induce apoptosis in the target cells. Taking advantage of the human apoptosis inducing proteins Bak and Bax as novel killing components, we have now constructed new chimeric proteins targeted against the human FcepsilonRI, expressed mainly on mast cells and basophils. These cells are the main effectors of the allergic response. Treatment of the target cells with the new chimeric proteins, termed Fcepsilon-Bak/Bax, had a dramatic effect on cell survival, causing apoptosis. The effect was specific to cells expressing the FcepsilonRI of both human and, very unexpectedly, also of mouse origin. Moreover, interaction of the chimeric proteins with the mast cells did not cause degranulation. Fcepsilon-Bak/Bax are new chimeric proteins of human origin and, as such, are expected to be both less immunogenic and less toxic and, thus, may be specific and efficient reagents for the treatment of allergic diseases.

Diagnosis of mastocytosis: general histopathological aspects, morphological criteria, and immunohistochemical findings

An increase in mast cell (MC) numbers in hemopoietic tissues may be associated with (a) primary neoplastic MC disease (mastocytosis); (b) non-mast cell lineage myelogenous disorders (myelodysplastic or myeloproliferative syndromes and myeloid leukemias); or (c) reactive, i.e. non-clonal states (MC hyperplasia and reactive mastocytosis). However, the histologic discrimination between hyperplastic states and neoplastic MC proliferative disorders is sometimes very difficult. MC hyperplasia is characterized by a diffuse increase in mature, round or spindle-shaped, metachromatic MC that are loosely scattered throughout the tissue and do not form dense focal infiltrates, even in states of marked hyperplasia. However, loosely scattered MC are also a prominent feature of many cases of myelodysplastic syndromes and acute leukemia involving the MC lineage. In contrast, the demonstration of dense, focal and/or diffuse MC infiltrates can be regarded as indicative of primary MC disease/mastocytosis. In addition to the highly diagnostic focal MC infiltrates, mastocytosis may also present with a predominantly diffuse or a mixed (diffuse and focal) infiltration pattern. The relatively rare diffuse pattern is usually dominated by atypical, often hypogranulated or even non-metachromatic MC and is associated with the aggressive or frankly malignant subtypes of systemic mastocytosis and MC leukemia. Although the demonstration of MC infiltrates in Giemsa-stained tissue sections is still very important for the diagnosis of mastocytosis, immunohistochemical techniques using antibodies against MC-associated antigens such as tryptase or c-kit (CD117) are essential for the identification of highly atypical, hypogranulated MC, especially in MC leukemia, and for the detection of small and even minute MC infiltrates.

Familial cutaneous mastocytosis

Cutaneous mastocytosis appears to occur sporadically; however, familial inheritance has been reported in 50 families since the mid-1880s. We report four cases of telangiectasia macularis eruptiva perstans (TMEP) occurring in three generations of a family. Whereas most patients with TMEP manifest in adulthood, all of the members of this family developed initial lesions during childhood. This is the third documented instance of familial mastocytosis affecting members of three generations, and the first report of familial TMEP. Although the inheritance pattern is unknown, the presentation of disease in this family further supports the hypothesis of an autosomal dominant mode of transmission with incomplete penetrance.

The many faces of systemic mastocytosis

OBJECTIVE

This short review article will augment the reader's knowledge of mast cell physiology and will offer an overview of current information on the pathophysiology, heterogeneity, and treatment of human mastocystosis.

DATA SOURCES AND STUDY SELECTION

Articles published since 1980, textbooks, information from computerized databases, references identified from bibliographies of relevant articles, and books published in the last 10 years.

RESULTS AND CONCLUSIONS

Mastocytosis is a complex disease with a multitude of clinical presentations, often misdiagnosed, which can embrace characteristics of other diseases and generate a chameleon-like picture. Mast cells possess many important physiologic functions in the human body, but as a consequence of poorly understood events, they can also start a cascade of pathologic reactions. Although a great deal is known about mechanisms involved in physiologic and pathologic processes of mast cells, many areas are waiting to be explored in this millennium.

Nodular and bullous cutaneous mastocytosis of the xanthelasmoid type: case report

Severe generalized nodular and bullous mastocytosis of the xanthelasmoid type is described in a 7-month-old boy. Reddish to yellowish-brown xanthelasmoid papules and nodules first developed in the inguinal region a few weeks after birth and then progressively spread to cover nearly the entire body surface. There was severe pruritus and recurrent episodes of blistering. The diagnosis of cutaneous mastocytosis of the xanthelasmoid type with subepidermal bullae was confirmed by skin biopsies showing solid and deeply penetrating infiltrates of metachromatic mast cells under light and electron microscopy. Systemic involvement of other organs, however, was excluded by bone scintigraphy, abdominal ultrasound, bone marrow aspiration and echocardiography. The extensive skin involvement was reflected in highly elevated urinary levels of histamine (263.4 microg L(-1)) and its metabolite N-methylimidazole acetic acid (20.8 mg L(-1)). The patient was systematically well and received only symptomatic treatment. Over a period of 1 year, the condition gradually improved, and the skin lesions began to flatten and regress.

Temporary response of localized intracranial mast cell sarcoma to combination chemotherapy

Cerebral involvement of systemic mastocytosis and intracranial sarcoma of myelogenic origin are well known entities. An 8-year-old girl with an isolated cerebral mast cell tumor is presented. Specific histopathologic stains were used to confirm the diagnosis detecting immunophenotype and proliferative activity. Treatment with irradiation, intrathecal cytarabine, and interferon-alpha2b did not induce regression whereas polychemotherapy did. Systemic combination chemotherapy led to marked transient tumor regression in this proliferating mast cell sarcoma in an unusual intracranial location.

Treatment of systemic mast cell disorders

The heterogeneous nature of disease manifestations in mastocytosis requires the individualization of therapy to each patient's clinical presentation and prognosis. The mainstay of treatment for most categories of mastocytosis are H1 and H2 antihistamines with the addition of corticosteroids for more severe symptoms. This article presents a summary of treatment strategies for indolent and aggressive forms of mastocytosis along with a discussion of future therapeutic directions.

New approaches to therapy for mastocytosis. A case for treatment with kit kinase inhibitors

Some forms of mastocytosis are caused by c-kit mutations which cause constitutive activation of kit kinase. Compounds that inhibit kit kinase, such as indolinones, are therefore attractive as potential therapeutic agents. A hierarchy exists in the ability of compounds to inhibit kit kinase effectively. Some compounds can inhibit ligand-induced activation of wild-type receptor but are ineffective against constitutively activated mutants. Other compounds can inhibit ligand-induced activation of wild-type kit and ligand-independent activation by juxtamembrane domain mutations but not activation by activation loop mutations. Still others effectively inhibit wild-type kit and constitutively activated kit bearing either juxtamembrane or kinase domain mutations and kill the neoplastic mast cells expressing these mutants. No therapy currently exists that specifically targets a cause of mastocytosis, but there are good reasons to believe that kit kinase inhibitors may fulfill that role someday.

Telangiectasia macularis eruptiva perstans

Telangiectasia macularis eruptiva perstans (TMEP) is a form of mastocytosis. It is an uncommon condition, particularly in children. The disorder is characterized by telangiectatic macules and generally has a good prognosis, with little tendency to urticate or cause constitutional symptoms. We report a girl who presented at age 2 with a 6-month history of erythematous macules on her arms and legs. The lesions were larger and possessed a more angular configuration than classic telangiectases. They slowly spread to her torso and face; there were no associated constitutional symptoms. Histopathologic examination showed dilated capillaries and increased numbers of mast cells, consistent with TMEP. Mastocytosis should be considered in patients presenting with telangiectatic lesions that are atypical in appearance, distribution, or onset.

Evaluation of intestinal permeability and gluten sensitivity in Soft-Coated Wheaten Terriers with familial protein-losing enteropathy, protein-losing nephropathy, or both

OBJECTIVE

To evaluate intestinal permeability and gluten sensitivity in a family of Soft-Coated Wheaten Terriers (SCWT) affected with protein-losing enteropathy (PLE), protein-losing nephropathy (PLN), or both.

ANIMALS

6 affected adult dogs.

PROCEDURE

Intestinal biopsy specimens, urine protein-to-creatinine ratio, serum concentrations of albumin and globulin, and concentration of alpha1-protease inhibitor in feces were evaluated before, during, and 13 weeks after daily administration of 10 g of gluten for 7 weeks. Eosinophils and lymphocytes-plasmacytes were enumerated in intestinal biopsy specimens. Intestinal permeability was evaluated before and during the sixth week of gluten administration via cellobiose-mannitol and chromium-EDTA absorption tests.

RESULTS

Serum globulin concentration decreased significantly after prolonged administration of gluten. Although not significant, there was an increase in lymphocytes-plasmacytes and a decrease in eosinophils in intestinal biopsy specimens. Furthermore, these counts were greater than those reported for clinically normal dogs. Gluten administration did not increase intestinal permeability.

CONCLUSIONS AND CLINICAL RELEVANCE

Daily administration of gluten was associated with a significant decrease in serum globulin concentration in SCWT affected with PLE or PLN, but other variables remained unchanged. Although enhanced wheat-gluten sensitivity may be one factor involved in the pathogenesis of PLE or PLN in SCWT, this syndrome does not appear to be the result of a specific sensitivity to gluten.

Mast cells in leprosy and leprosy reaction

BACKGROUND

Mast cells can be visualized in routine, acid-fast-staining, paraffin tissue section as metachromatic staining cells, and can be activated to release inflammatory mediators which play a role in the cell-mediated immune response.

METHODS

Skin biopsy tissues were taken from the most active skin lesion of each leprosy patient at the time of diagnosis (nonreactional group) and at the time of reaction (reactional group) during the years 1994-1997 in the leprosy clinic at the Department of Dermatology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Thailand. Mast cells were identified by metachromatic staining (purple) in Fite's stain sections and reported as the average number of cells per high power field in three compartments: at the center and periphery of the granuloma and in the interstitium. The data were analyzed in three groups: nonreactional group, type I, and type II leprosy reactions. The mast cell count of each group and each compartment of the section, expressed as the mean +/- standard error, was compared.

RESULTS

A total of 95 persons were included in the study, but 108 tissue sections were obtained due to nine cases having more than one section. Of these patients, 63 cases (66.32%) had no reaction, 19 cases (20%) had type I reaction, and 13 cases had type II reaction. There was no difference in age and sex among these groups. The mast cell count in the interstitium was higher than that within the granuloma, both at the center and at the periphery, in every type, and the count in this area reduced significantly in leprosy reactions, both type I and type II, compared with the nonreactional group.

CONCLUSIONS

The change in the average mast cell number in nonreactional leprosy and leprosy reactions may indicate the important role of mast cells in dynamic changes in the cell-mediated immune response in leprosy and leprosy reactions.

Diagnostic Value of Calretinin in Mast Cell Lesions of the Skin

The diagnosis of mast cell lesions of the skin can occasionally be challenging. Calretinin, a 29 kD neuron-specific calcium-binding protein found mostly in the CNS and retina, has been shown to be a positive marker for mesotheliomas, and is also expressed in mast cells. We studied the diagnostic value of calretinin and compared our results to other established ancillary studies used to identify mast cells, such as Toluidine blue and the Leder stain. Sixty-three cases were studied, including 45 mast cell lesions (22 urticaria pigmentosum, 17 mastocytomas, and six telangiectasia macularis eruptiva perstans [TMEP]), seven nevi, three melanomas, four granular cell minors of the skin, three cutaneous lymphomas, and one granulocytic sarcoma. Patients ranged in age from less than 1 to 85 years with a median age of 29 years. The group consisted of 36 females and 27 males. Calretinin was expressed in all 45 mast cell lesions. Negative staining for calretinin was seen in all skin lesions that potentially could be considered in the differential diagnosis of mast cell lesions such as nevi, melanomas, lymphomas, and the granulocytic sarcoma. However, calretinin expression was noted in four/four granular cell tumors. Leder and Toluidine blue stains were positive in all 45 mast cell lesions, and all nonmast cell lesions were negative with these stains. In conclusion, our study demonstrated that calretinin is a sensitive and specific marker of mast cells and can be an aid in distinguishing mast cell lesions from other skin lesions considered in the differential diagnosis. Calretinin may be more sensitive than the currently used special stains utilized to diagnose mast cell lesions having few diagnostic mast cells such as TMEP. However, this immunoperoxidase stain does not add significant diagnostic information in most cases, when compared with the currently used less expensive special stains and, therefore, is not cost-effective. Int J Surg Pathol 8(2):119-122, 2000

Familial mastocytosis associated with neurosensory deafness

Mastocytosis is a disease characterized by excessive accumulation of mast cells in different tissues and symptoms caused by the release of mast cell mediators. The skin is frequently directly involved in mastocytosis. The disease is rarely seen in other members of the subjects' family; only 49 cases of familial mastocytosis have been reported. Familial mastocytosis associated with hearing loss may represent a newly described inherited entity. We describe a brother and sister exhibiting skin mastocytosis and neurosensory deafness, associated with a history of hearing loss in their father's family. The appearance of the mast cell disease in two siblings, who presented with similar clinical features represents a familial form of mastocytosis; the association with an inherited form of deafness may constitute a new syndrome. Our patients show several features similar to some previously reported cases but different insofar that additional congenital defects and mental retardation are absent.

Mastocytosis with skin manifestations: current status

AIM

To review our present knowledge about mastocyte origin, mastocytosis classification and management.

METHODS

Literature review.

RESULTS

Mastocytoses are chronic and recurrent disorders with symptoms which might either be limited only to the skin or to internal organs as well. The mastocytes, coming from bone marrow progenitor cells, migrate to tissues where they participate in inflammation and in cellular immunity as well as in the metabolism of connective and osseous tissues. Their proliferation causes the appearance of mastocytoses. The classification of the clinical manifestations of the mastocytoses into cutaneous, reactive (under the influence of the degranulator factors) and systemic disease, facilitates dialog among clinicians. Determination of prognosis and appropriate therapeutic regimens depend on individual features.

CONCLUSIONS

Mastocytosis diagnosis is verified by histological study of skin lesion biopsy material. Management is symptomatic and unfortunately does not eradicate the disease.

Bullous mastocytosis: a fatal outcome

A 6-week-old boy was referred with a generalized bullous rash since birth. Examination revealed bullous mastocytosis with initially no evidence of systemic involvement. Hepatosplenomegaly was noted at 6 months, and at 12 months he was found to have generalized lymphadenopathy. He developed bouts of vomiting associated with increased blistering. At 17 months he had sudden collapse following a brief bout of vomiting and was apneic and asystolic on arrival at the emergency department. The cause of death was attributed to massive hypotension secondary to mast cell degranulation. Although childhood mastocytosis has a favorable course in general, the subset of children with congenital bullous mastocytosis is at higher risk of sudden death and a more guarded prognosis should be given.

Differential effect of flavonoids on inhibition of secretion and accumulation of secretory granules in rat basophilic leukemia cells

Rat basophilic leukemia (RBL) cells resemble mucosal mast cells (MMC) and develop few secretory granules under normal culture conditions. RBL cells have been used for the study of secretion and for the possible involvement of MMC in food allergies and irritable bowel syndrome (IBS). The flavonoid quercetin is one of very few molecules that inhibit RBL cell proliferation and constitutive histamine release; it also induces synthesis of rat mast cell protease (RMCP) II and accumulation of secretory granules. Even though quercetin is available as a food supplement over the counter, some early studies had indicated it may be carcinogenic. We, therefore, compared the effect of quercetin to that of other flavonoids with similar structure. Flavone, kaempferol, myricetin and morin were investigated for their action on RBL cell secretion of beta-hexosaminidase stimulated by anti-DNP serum and DNP-BSA, as well as on secretory granule development. Quercetin, myricetin and kaempferol inhibited RBL cell secretion significantly only at 10(-4) M. Flavone inhibited secretion at 10(-4), 10(-5) and 10(-6) M; it also maximally induced secretory granule accumulation as evidenced by light and electron microscopy. In contrast, morin which differs structurally only by one extra hydroxyl group had minimal effect. These results indicate that flavone is capable of inhibiting stimulated secretion and inducing secretory granule development at reasonable concentrations.

Activating and dominant inactivating c-KIT catalytic domain mutations in distinct clinical forms of human mastocytosis

Human mastocytosis is characterized by increased mast cells. It usually occurs as a sporadic disease that is often transient and limited in children and persistent or progressive in adults. The c-KIT protooncogene encodes KIT, a tyrosine kinase that is the receptor for mast cell growth factor. Because mutated KIT can transform cells, we examined c-KIT in skin lesions of 22 patients with sporadic mastocytosis and 3 patients with familial mastocytosis. All patients with adult sporadic mastocytosis had somatic c-KIT mutations in codon 816 causing substitution of valine for aspartate and spontaneous activation of mast cell growth factor receptor (P = 0.0001). A subset of four pediatric onset cases with clinically unusual disease also had codon 816 activating mutations substituting valine, tyrosine, or phenylalanine for aspartate. Typical pediatric patients lacked 816 mutations, but limited sequencing showed three of six had a novel dominant inactivating mutation substituting lysine for glutamic acid in position 839, the site of a potential salt bridge that is highly conserved in receptor tyrosine kinases. No c-KIT mutations were found in the entire coding region of three patients with familial mastocytosis. We conclude that c-KIT somatic mutations substituting valine in position 816 of KIT are characteristic of sporadic adult mastocytosis and may cause this disease. Similar mutations causing activation of the mast cell growth factor receptor are found in children apparently at risk for extensive or persistent disease. In contrast, typical pediatric mastocytosis patients lack these mutations and may express inactivating c-KIT mutations. Familial mastocytosis, however, may occur in the absence of c-KIT coding mutations.

Clustering of activating mutations in c-KIT's juxtamembrane coding region in canine mast cell neoplasms

The proto-oncogene c-KIT encodes a growth factor receptor, KIT, with ligand-dependent tyrosine kinase activity that is expressed by several cell types including mast cells. c-KIT juxtamembrane coding region mutations causing constitutive activation of KIT are capable of transforming cell lines and have been identified in a human mast cell line and in situ in human gastrointestinal stromal tumors, but have not been demonstrated in situ in neoplastic mast cells from any species. To determine whether c-KIT juxtamembrane mutations occur in the development of mast cell neoplasms, we examined canine mastocytomas, which are among the most common tumors of dogs and which often behave in a malignant fashion, unlike human solitary mastocytomas. Sequencing of c-KIT cDNA generated from tumor tissues removed from seven dogs revealed that three of the tumors contained a total of four mutations in an intracellular juxtamembrane coding region that is completely conserved among vertebrates. In addition, two mutations were found in three mast cell lines derived from two additional dogs. One mutation from one line matched that found in situ in one of the tumors. The second was found in two lines derived from one dog at different times, indicating that the mutation was present in situ in the animal. All five mutations cause high spontaneous tyrosine phosphorylation of KIT. Our study provides in situ evidence that activating c-KIT juxtamembrane mutations are present in, and may therefore contribute to, the pathogenesis of mast cell neoplasia. Our data also suggest an inhibitory role for the KIT juxtamembrane region in controlling the receptor kinase activity.

Diffuse cutaneous mastocytosis responding to cyproheptadine

A 3-month-old male infant was referred to our department with a generalized brown, thickened leathery skin and blisters which had been present since birth; the blisters developed recurrently at sites of minor trauma, healing without scar formation, although Darier's sign was positive. Microscopically, biopsy specimens showed a dense dermal band-like infiltrate with mast cells, whereas a biopsy from a vesicle showed subepidermal bulla formation. Physical examination did not reveal any systemic involvement with mastocytosis and the patient was treated with cyproheptadine, which has considerable anti-serotonin activity and, interestingly, reduced the degree of blistering; this treatment might therefore be tried in other cases.

Cutaneous and gastrointestinal mastocytosis associated with cerebral toxoplasmosis

A patient with systemic cutaneous and gastrointestinal mastocytosis and associated meningoencephalitic toxoplasmosis is reported. The simultaneous occurrence of the two conditions and their regression after treatment of the toxoplasmosis suggest a possible relationship between the mast cell proliferation and the parasitic infection. Mast cell activation and stimulation may be transitory in response to a stimulus, causing reactional mastocytosis.

Diagnostic value of immunostaining for tryptase in patients with mastocytosis

The term "mastocytosis" is used to describe a heterogeneous group of disorders characterized by abnormal growth and accumulation of mast cells (MCs). Cutaneous and systemic variants exist. Systemic mastocytosis may show an indolent or malignant clinical course. In malignant mastocytosis (MM), the diagnosis often is missed because the MCs are morphologically abnormal and lack metachromatic granules or the underlying histologic picture is complex. The cytoplasmic serine protease tryptase is produced by MCs and is thought to be expressed at all stages of MC maturation. To assess the diagnostic value of tryptase staining in mastocytosis, tissue sections from 93 patients with mastocytosis, including MM (n = 37), systemic indolent mastocytosis (n = 47), urticaria pigmentosa (n = 5), MC leukemia (n = 2), and solitary skin mastocytoma (n = 2) were stained with the antitryptase antibody G3. The results were compared with those of Giemsa and chloroacetate esterase (CAE) staining. Using antitryptase antibody G3, MC infiltrates were identified in all patients examined, including those with MM (37 of 37), and virtually all the neoplastic MCs (> 95%) appeared to react with G3. In MM, significantly fewer MCs were positive in Giemsa (54.5%; p < 0.05) and CAE (78.8%; p < 0.05). Moreover, G3 produced clear diagnostic staining in all cases of MM, but the proportion of cases with clear diagnostic results (> 10% of neoplastic cells positive) was considerably lower with Giemsa (48.6%; p < 0.05) and CAE (75.7%; p < 0.05) staining. By contrast, tryptase, Giemsa, and CAE produced diagnostic staining of MCs in virtually all cases of systemic indolent mastocytosis, urticaria pigmentosa, and solitary skin mastocytoma. In systemic mastocytosis, survival was significantly reduced in cases with Giemsa-/tryptase+ or CAE-/tryptase+ tumor cells compared to those cases with Giemsa+ or CAE+ MC infiltrates (p < 0.001).

Systemic mastocytosis presenting as profound cardiovascular collapse during anaesthesia

Mastocytosis is a rare disorder with serious anaesthetic implications. Anaesthetic management is hazardous since trauma, stress, extremes of temperature and drugs may precipitate intra-operative mast cell degranulation. Release of histamine and other mast cell mediators can lead to profound cardiovascular collapse and even death. We present a case report of a patient with mastocytosis who suffered cardiac arrest during anaesthesia. Anaphylactoid/anaphylactic shock may be delayed and lack supporting signs of histamine release such as cutaneous flushing and bronchospasm.

Murine cutaneous mastocytosis and epidermal melanocytosis induced by keratinocyte expression of transgenic stem cell factor

The growth and differentiation of mast cells and melanocytes require stem cell factor (SCF), the ligand for the kit receptor tyrosine kinase. SCF may exist as a membrane-bound or soluble molecule. Abnormalities of the SCF-kit signaling pathway, with increased local concentrations of soluble SCF, have been implicated in the pathogenesis of the human disease cutaneous mastocytosis, but have not yet been shown to play a causal role. To investigate both the potential of SCF to cause mastocytosis and its role in epidermal melanocyte homeostasis, we targeted the expression of SCF to epidermal keratinocytes in mice with two different transgenes controlled by the human keratin 14 promoter. The transgenes contained cDNAs that either produced SCF, which can exist in both membrane-bound and soluble forms, or SCF, which remains essentially membrane bound. Murine epidermal keratinocyte expression of membrane-bound/ soluble SCF reproduced the phenotype of human cutaneous mastocytosis, with dermal mast cell infiltrates and epidermal hyperpigmentation, and caused the maintenance of a population of melanocytes in the interadnexal epidermis, an area where melanocytes and melanin are found in human skin but where they are not typically found in murine skin. Expression of membrane-bound SCF alone resulted in epidermal melanocytosis and melanin production, but did not by itself cause mastocytosis. We conclude, first, that a phenotype matching that of human mastocytosis can be produced in mice by keratinocyte overproduction of soluble SCF, suggesting a potential cause of this disease. Second, we conclude that keratinocyte expression of membrane-bound SCF results in the postnatal maintenance of epidermal melanocytes in mice. Since the resulting animals have skin that more closely approximates human skin than do normal mice, their study may be more relevant to human melanocyte biology than the study of skin of normal mice.

Diagnosis of mastocytosis by fine-needle aspiration cytology

We report a case of a 28-yr-old man in whom mastocytosis was diagnosed by fine-needle aspiration (FNA) of enlarged periaortic lymph nodes. FNA cytology revealed numerous mast cells characterized by cells having round to oval eccentrically placed nuclei and associated coarsely granular cytoplasm, most conspicuous on Diff-Quik- and Giemsa-stained smears. Lymphocytes, histiocytes, and occasional plasma cells were present in the background. We believe this paper to be the first reported case of mastocytosis diagnosed by FNA. The case demonstrates the utility of FNA in evaluating lymphadenopathy occurring in mastocytosis.

Mast cells in clinical dermatology

Recent advances in cutaneous mast cell biology are briefly reviewed with special reference to our own studies on cultured human mast cells. Of note are the heterogeneity of mastocytosis, the important participation of mast cells in allergic inflammation by releasing cytokines and the inhibitory effect of histamine release from mast cells by phototherapy. It is also stressed that mast cells play a major role in tissue remodelling. These novel findings suggest that mast cells can no longer be regarded simply as cells that initiate immediate allergic reactions, but that they are responsible for various chronic inflammatory or immunological events through cytokine-dependent leucocyte recruitment. The regulation of mast cell activation should be a critical issue and, thus, a promising therapeutic approach in clinical dermatology.

Heterogeneity of mast cells in mastocytosis and inhibitory effect of ketotifen and ranitidine on indolent systemic mastocytosis

BACKGROUND

Mastocytosis is a disorder of mast cell proliferation that occurs in both cutaneous and systemic forms. The most frequent site is the skin.

OBJECTIVE

The mast cell subtype of two patients with mastocytosis was investigated.

METHODS

Immunohistochemical studies were performed on the skin or gastric mucosa or both of the two patients. Blood and urine levels of various mediators were measured for one patient.

RESULTS

Mast cells containing tryptase and chymase were the only type seen in the skin lesions of an 11-month-old boy with urticaria pigmentosa. Mast cells containing tryptase were predominant in lesions of the skin and gastric mucosa of a 41-year-old man with indolent systemic mastocytosis. However, mast cells containing tryptase and chymase were predominant in the nonlesional and the normal skin of this patient. Tryptase-positive cells were more numerous in lesional skin than nonlesional skin and normal skin. Elevated blood and urine levels of various mediators were decreased by means of combination therapy with ketotifen and ranitidine.

CONCLUSION

In indolent systemic mastocytosis, mast cell dynamics involve only cells containing tryptase. Release of mediators from mast cells may be inhibited by means of combination therapy with histamine H1 and H2 receptor antagonists.

Epidermal T cells: their functional role and disease relevance for dermatologists

T cells found within the epidermis in inflammatory dermatoses are generally accepted as making a major contribution to epidermal damage. On the other hand, those T cells residing in the murine epidermis are supposed to play an important role in protecting the epidermis from potentially dangerous immune reactions. Overwhelming evidence has accumulated that dendritic epidermal T cells (DETC) expressing monomorphic TCR gammadelta are responsible for the protection of epidermal structures against skin tumor, bacterial infection, and autoimmune attack. In animals congenitally lacking these gammadelta+ DETC, the epidermis is populated with bone marrow-derived TCR alphabeta+, CD8+ DETC. Although it remains unclear whether this subset of DETC could home to the epidermis to substitute for the physiologic function of gammadelta+ DETC or whether they would be pathologically relevant to epidermal injury, it should be noted that this subset represents the major fraction of T cells present in normal human epidermis and the most abundant in the lesional epidermis of fixed drug eruption (FDE). Because they are shown to kill target cells including keratinocytes upon stimulation and utilize a very limited range of TCR V alpha and Vbeta gene families, localized epidermal injury in FDE lesions would be mediated by activation of these epidermal T cells with autoaggressive potential. Epidermal T cells are thus likely to form several T-cell populations with different immunologic functions that are triggered by different modes of stimulation. Immune homeostasis in the epidermis would rely on a delicate balance between at least two types of epidermal T cells: autoaggressive T cells and protective T cells.

Chymase cleavage of stem cell factor yields a bioactive, soluble product

Stem cell factor (SCF) is produced by stromal cells as a membrane-bound molecule, which may be proteolytically cleaved at a site close to the membrane to produce a soluble bioactive form. The proteases producing this cleavage are unknown. In this study, we demonstrate that human mast cell chymase, a chymotrypsin-like protease, cleaves SCF at a novel site. Cleavage is at the peptide bond between Phe-158 and Met-159, which are encoded by exon 6 of the SCF gene. This cleavage results in a soluble bioactive product that is 7 amino acids shorter at the C terminus than previously identified soluble SCF. This research shows the identification of a physiologically relevant enzyme that specifically cleaves SCF. Because mast cells express the KIT protein, the receptor for SCF, and respond to SCF by proliferation and degranulation, this observation identifies a possible feedback loop in which chymase released from mast cell secretory granules may solubilize SCF bound to the membrane of surrounding stromal cells. The liberated soluble SCF may in turn stimulate mast cell proliferation and differentiated functions; this loop could contribute to abnormal accumulations of mast cells in the skin and hyperpigmentation at sites of chronic cutaneous inflammation.