Adult-onset urticaria pigmentosa and systemic mast cell disease

Kidney and urinary tract involvement in systemic mastocytosis

Systemic mastocytosis (SM) is a disorder of excessive mast cell accumulation in tissues due to a somatic gain-of-function mutation, commonly in the KIT gene, which prevents apoptosis of mast cells. Whereas bone marrow, skin, lymph nodes, spleen and gastrointestinal tract are commonly involved, kidneys are rarely involved directly by SM. However, there are increasing reports of indirect kidney involvement in patients with SM. Novel anti-neoplastic agents to treat advanced forms of SM include non-specific tyrosine kinase inhibitors, which are reported to be associated with kidney dysfunction in some patients. SM is also associated with immune-mediated glomerulonephritis (GN) such as mesangioproliferative GN, membranous nephropathy and diffuse proliferative GN. Kidney injury, in the form of monoclonal deposition disease and primary light chain amyloidosis, is reported in SM associated with plasma cell dyscrasia. In this narrative review we discuss the various ways kidneys (and the urinary tract) are involved in patients with SM.

Identification of microRNAs regulating the developmental pathways of bone marrow derived mast cells

Background

MicroRNAs (miRNAs) play important roles in leukocyte differentiation, although those utilised for specific programs and key functions remain incompletely characterised. As a global approach to gain insights into the potential regulatory role of miRNA in mast cell differentiation we characterised expression in BM cultures from the initiation of differentiation. In cultures enriched in differentiating mast cells we characterised miRNA expression and identified miRNA targeting the mRNA of putative factors involved in differentiation pathways and cellular identity. Detailed pathway analysis identified a unique miRNA network that is intimately linked to the mast cell differentiation program.

Methodology/Principal Findings

We identified 86 unique miRNAs with expression patterns that were up- or down- regulated at 5-fold or more during bone marrow derived mast cells (BMMC) development. By employing TargetScan and MeSH databases, we identified 524 transcripts involved in 30 canonical pathways as potentially regulated by these specific 86 miRNAs. Furthermore, by applying miRanda and IPA analyses, we predict that 7 specific miRNAs of this group are directly associated with the expression of c-Kit and FcεRIα and likewise, that 18 miRNAs promote expression of Mitf, GATA1 and c/EBPα three core transcription factors that direct mast cell differentiation. Furthermore, we have identified 11 miRNAs that may regulate the expression of STATs-3, -5a/b, GATA2 and GATA3 during differentiation, along with 13 miRNAs that target transcripts encoding Ndst2, mMCP4 and mMCP6 and thus may regulate biosynthesis of mast cell secretory mediators.

Conclusions/Significance

This investigation characterises changes in miRNA expression in whole BM cultures during the differentiation of mast cells and predicts functional links between miRNAs and their target mRNAs for the regulation of development. This information provides an important resource for further investigations of the contributions of miRNAs to mast cell differentiation and function.

Adult-onset mastocytosis in the skin is highly suggestive of systemic mastocytosis

Adult-onset urticaria pigmentosa/mastocytosis in the skin almost always persists throughout life. The prevalence of systemic mastocytosis in such patients is not precisely known. Bone marrow biopsies from 59 patients with mastocytosis in the skin and all available skin biopsies (n=27) were subjected to a meticulous cytological, histological, immunohistochemical, and molecular analysis for the presence of WHO-defined diagnostic criteria for systemic mastocytosis: compact mast cell infiltrates (major criterion); atypical mast cell morphology, KIT D816V, abnormal expression of CD25 by mast cells, and serum tryptase levels >20 ng/ml (minor criteria). Systemic mastocytosis is diagnosed when the major diagnostic criterion plus one minor criterion or at least three minor criteria are fulfilled. Systemic mastocytosis was confirmed in 57 patients (97%) by the diagnosis of compact mast cell infiltrates plus at least one minor diagnostic criterion (n=42, 71%) or at least three minor diagnostic criteria (n=15, 25%). In two patients, only two minor diagnostic criteria were detectable, insufficient for the diagnosis of systemic mastocytosis. By the use of highly sensitive molecular methods, including the analysis of microdissected mast cells, KIT D816V was found in all 58 bone marrow biopsies investigated for it but only in 74% (20/27) of the skin biopsies. It is important to state that even in cases with insufficient diagnostic criteria for systemic mastocytosis, KIT D816V-positive mast cells were detected in the bone marrow. This study demonstrates, for the first time, that almost all patients with adult-onset mastocytosis in the skin, in fact, have systemic mastocytosis with cutaneous involvement.

Systemic Mastocytosis: Clinical Manifestations and Differential Diagnosis

Mast cells produce symptoms by local and remote effects of mediator release and by their presence in increased numbers in normal tissue and bone marrow, where they damage and impair normal organ function. Moreover, mast cells are long-lived and heterogeneous in their response to secretagogues and to inhibitors of mediator release. Clinicians sorting out the diagnosis of SM on the basis of presenting signs and symptoms continue to have their diagnostic skills challenged because of the rarity of this disorder, the fact that many symptoms of SM are present in more common disorders, and the multiple guises that SM may assume at the time of presentation.

Treatment of systemic mast cell disease with 2-chlorodeoxyadenosine

We used three to six courses of 2-chlorodeoxyadenosine (2-CdA) (2-h infusion at 0.14 mg/kg per day x 5 days) given over a period of 3-36 months to treat four patients with aggressive systemic mast cell disease (SMCD) that was resistant to interferon-alpha (IFN-alpha). Treatment with 2-CdA resulted in a major response in two patients and a good partial response in one other patient (75% overall response). Treatment was well tolerated and duration of remission in responding patients ranges from 2 months to 4+ years since the completion of treatment with 2-CdA.

Assessment of the extent of cutaneous involvement in children and adults with mastocytosis: relationship to symptomatology, tryptase levels, and bone marrow pathology

BACKGROUND

Cutaneous involvement occurs in most patients with systemic mastocytosis.

OBJECTIVE

We sought to determine whether the extent of cutaneous involvement is predictive of systemic disease.

METHODS

In a prospective survey of 48 adults and 19 children, the extent and density of cutaneous lesions were compared with patient history, symptoms, internal organ involvement, serum total mast cell tryptase level, and bone marrow pathology.

RESULTS

Cutaneous lesions in children were of a greater mean and maximum diameter, but similar in extent and density compared with lesions in adults. In adults with skin lesions, the extent of lesions correlated to disease duration. Adults with extensive cutaneous disease experienced more pruritus and flushing. Fatigue, splenomegaly, and hepatomegaly were more frequent in adults without cutaneous involvement; and in those with a greater density of lesions and disease duration. Increased tryptase levels were found in children and adults with systemic disease and correlated to skin lesion density and bone marrow pathology.

CONCLUSION

An examination of the extent and density of cutaneous lesions in adults helps identify those with more extensive extracutaneous disease and, thus, requiring a more thorough evaluation.

Mastocytosis: molecular mechanisms and clinical disease heterogeneity

Systemic mastocytosis has one unifying feature: an unexplained and pathologic increase in mast cells in specific tissues. This observation, along with clinical disease heterogeneity has long suggested that mastocytosis is a disease of complex etiology. At the same time, the last decade has witnessed significant progress in identifying the critical elements that regulate mast cell growth and development. Human mast cells are now known to arise from CD34(+) progenitors, particularly under the influence of stem cell factor (SCF). This information in turn led to the critical observation that a substantial number of patients with mastocytosis exhibit activating mutations in c-kit, the receptor for SCF. And while this observation may well be key in understanding mastocytosis, this mutation alone does not explain all heterogeneity. It now appears that other influences such as genetic polymorphisms within the host may influence the course of disease in those with KIT mutations; and that the search for additional molecular events capable of creating disease diversity must continue.

Diagnosis of mastocytosis: value of cytochemistry and immunohistochemistry

The diagnosis of mastocytosis or mast cell disease may be difficult sometimes because of the wide variety of clinical presentation, abnormal morphology of mast cells, and variation in histologic features which may mimic varieties of other diseases. Over the years, several cell type specific cytochemical and immunochemical markers have been used for the identification of hematopoietic cells in order to establish the accurate diagnosis of mastocytosis and their associated hematologic diseases. Cytochemical stain for aminocaproate esterase is the most specific enzyme marker for identification of mast cells on cytologic specimens and the immunohistochemical stain for tryptase and/or c-kit has also been established as a sensitive and specific marker for mast cells in paraffin sections.

Bone marrow involvement in cutaneous mastocytosis

BACKGROUND

Cutaneous mastocytosis is considered a relatively benign and indolent form of mast cell disease, which either ultimately regresses, remains stable or is only slowly progressive. Previously, it has been purported that no more than 60% of adult patients with cutaneous mastocytosis will have occult bone marrow involvement.

OBJECTIVES

To investigate the frequency of bone marrow involvement in patients with mastocytosis but without systemic symptoms.

METHODS

Bone marrow aspirate and trephine biopsy were performed in 13 consecutive patients with cutaneous mastocytosis attending our department.

RESULTS

All but one of these patients had evidence of bone marrow involvement. Bone marrow cytogenetic abnormalities have been found in patients with cutaneous mastocytosis: all our patients who were analysed showed a normal karyotype.

CONCLUSIONS

Bone marrow involvement is common in adults with cutaneous mastocytosis.

Mastocytosis and the skin

The most frequent site of organ involvement in individuals with any form of mastocytosis is the skin. Cutaneous lesions include urticaria pigmentosa, mastocytoma, diffuse and erythematous cutaneous mastocytosis, and telangiectasia macularis eruptiva perstans. The major histologic feature is an increase in the number of mast cells in the dermis. Treatment depends on the type of skin lesions.

Clinical advances in mastocytosis

Mastocytosis is a disease characterized by an abnormal proliferation of tissue mast cells. The events primarily responsible for mast cell proliferation in mastocytosis are largely unknown, but a derangement of the network involving c-kit receptor and its natural ligand (stem cell factor, which promotes mast cell growth and differentiation in man) is likely to have a primary role in this disease. Mastocytosis comprises a wide spectrum of clinical conditions determined by the degree of mast cell proliferation, the organ systems involved, the age at onset and the association with hematologic diseases. Mastocytosis can occur in a pediatric or an adult form. In both groups of patients, the disease may be limited to the skin (cutaneous mastocytosis) or be systemic, involving predominantly the bone marrow and the gastrointestinal tract. The symptoms in patients with mastocytosis are generally related to the increased release of mast-cell-derived mediators, such as histamine, prostaglandin D2, peptide leukotrienes, platelet-activating factor, heparin and proteolytic enzymes. The measurement of these chemical mediators (histamine, tryptase and prostaglandin D2 and their metabolites) in body fluids is useful for the diagnosis and the laboratory evaluation of patients with systemic mastocytosis. As little is known about the pathogenesis of the different forms of mastocytosis, the treatment of the majority of these patients is largely symptomatic.

The mast cell and mast cell disease

Mast cell disease or mastocytosis is a heterogeneous group of clinical disorders characterized by the proliferation and accumulation of mast cells in a variety of tissues, most often the skin. The signs and symptoms of mast cell disease are varied, dependent on the localization of mast cells in different organs and the local and systemic effects of mediators released from these cells. Although mast cell disease is most commonly identified in the skin, involvement of the skeletal, hematopoietic, gastrointestinal, cardiopulmonary, and central nervous systems may be seen. Clinical management of mastocytosis depends most heavily on knowledge of the diverse effects of mast cell mediators on various tissues and organs, the stimuli that can cause their release, and the different methods available for blocking the effects of these mediators.

Hematologic manifestations of systemic mast cell disease: a prospective study of laboratory and morphologic features and their relation to prognosis

PURPOSE

Systemic mast cell disease (SMCD) follows an indolent course in most patients, but a significant number of patients die of neoplastic hematologic disorders. Reviews of the literature and retrospective studies in a single institution have defined features that may be associated with a poor prognosis, but prospective studies have been lacking. Therefore, we prospectively analyzed the relationship between clinical, laboratory, and hematopathologic findings and clinical outcome in a series of 46 patients with mast cell disease. This analysis was employed to both define clinically useful prognostic variables and describe the histologic evolution of bone marrow mast cell infiltration and its relationship to hematologic neoplasia.

PATIENTS AND METHODS

Forty-six adult patients were referred to the National Institutes of Health (NIH) with clinical and/or pathologic evidence of mast cell proliferation. All patients had bone marrow examinations, and 10 patients underwent serial bone marrow biopsies. The diagnosis of SMCD required pathologic documentation of bone marrow mast cell infiltrates. The patients were followed for up to 13 years at the NIH (up to 30 years after the initial pathologic diagnosis of mast cell disease). Statistical analysis defined the correlation between variables and the presence of diagnostic bone marrow lesions. The Kaplan-Meier method was used to construct survival curves, and the effects of various variables on the survival time were examined.

RESULTS

Thirty-two of 46 patients (74%) had a bone marrow biopsy diagnostic for SMCD. The remaining 14 patients were considered to have cutaneous mast cell disease (CMCD). Univariate analysis showed that hepatosplenomegaly, alkaline phosphatase level, absolute lymphocyte count, and age at onset of symptoms were positively correlated with SMCD, whereas hemoglobin level was negatively associated with diagnostic bone marrow lesions. With multivariate analysis, only hemoglobin and absolute lymphocyte count remained as significant independent predictors of bone marrow findings. No CMCD patient died or had significant clinical deterioration in the 1- to 30-year period of follow-up (median = 8.5 years), whereas 10 of 32 SMCD patients (31%) died from 1 to 22 years after diagnosis (median = 2.5 years) (p less than 0.0001). Univariate analysis revealed the following variables as significantly increasing the risk of death in patients with SMCD: later onset of symptoms, absence of cutaneous mastocytosis, thrombocytopenia, elevated lactate dehydrogenase (LDH) level, anemia, bone marrow hypercellularity, qualitative peripheral blood smear abnormalities, elevated alkaline phosphatase level, and hepatosplenomegaly. Multivariate analysis showed that only the age at onset of symptoms and LDH levels were significant independent predictors of survival. Eight of the 10 SMCD patients who died had myeloproliferative or myelodysplastic syndromes or acute nonlymphocytic leukemia.

CONCLUSION

Our prospective study has defined a number of important variables in patients with clinical evidence of mast cell proliferation that can predict both the presence of SMCD and the likelihood of fatal disease. Since recent evidence suggests that mast cells derive from a bone marrow hematopoietic progenitor, SMCD may represent a myeloproliferative condition with the propensity to evolve into a neoplastic granulocytic disorder in a significant minority of patients.

A case of mastocytosis involving bone

A case of mastocytosis of the bone associated with urticaria pigmentosa was first suspected of being a generalized metastatic malignancy, for the radiographic manifestations were not connected by us with the patient's skin disease. The histologic diagnosis of systemic mastocytosis was also missed primarily, because mast cells are not visualized in the conventional hematoxylin and eosin staining of the histologic sections. Special stainings revealed mastocytosis. Irregular remodeling of the bone was also seen, which was consistent with the radiographically irregular bone structure.

The Skin in Mastocytosis

The most frequent site of organ involvement in patients with any form of mastocytosis is the skin. Cutaneous expressions include urticaria pigmentosa, mastocytoma, diffuse and erythrodermic cutaneous mastocytosis, and telangiectasia macularis eruptiva perstans. The cutaneous lesions tend to appear early in life. Although urticaria pigmentosa has been reported in 12 pairs of twins and one set of triplets, the majority of affected individuals have no familial association. Most patients with systemic mastocytosis have skin lesions; however, an occasional patient will have systemic disease with no other skin features than flushing. In lesional cutaneous sites and in non-lesional skin, there is an increase in the number of mast cells. Electron microscopy shows quantitative differences between lesional skin mast cells from patients with and without systemic disease. The mast cells from adult patients with systemic disease have a larger mean cytoplasmic area, nuclear size, and granule diameter. The granules contain predominantly grating/lattice structures. The cutaneous mast cells contain tryptase and chymase. They retain their functional reactivities to relevant secretory stimuli, such as C3a, morphine sulfate, and calcium ionophore A23187. Lesional skin contains histamine, leukotriene B4, prostaglandin D2, 5-hydroxyeicosatetraenoic acid, platelet-activating factor, and heparin. Treatment of the cutaneous manifestations includes the use of H1 and H2 antihistamines, oral disodium cromoglycate, psoralens plus ultraviolet A photochemotherapy, and potent topical corticosteroid preparations.

A clinical and histological study of urticaria pigmentosa: relationships between mast cell proliferation and the clinical and histological manifestations

In 21 cases of urticaria pigmentosa (UP), clinical and histological observations and evaluation of mast cell (MC) volume density in the lesions using a morphometric point counting method were performed. The mutual correlations between clinical and histological findings were statistically assessed by a method of multiple regression analysis. Clinical items employed in the analyses were as follows: sex, the age of onset, the age of biopsy, the biopsy, the duration of lesions, the type of skin lesions, sites involved, the presence or absence of Darier's sign of Darier's sign and symptoms, and serum histamine level. Histological items included the localization and infiltration pattern of MC, the level of basal melanosis, the presence or absence of inflammatory cell infiltration, and the MC volume density in the lesions. Statistical significance of the partial regression coefficients was obtained for 6 pairs of the criteria (p = 0.05), including the age of onset and the age of biopsy, the age of onset and the level of basal melanosis, the duration of lesions and the level of basal melanosis, and the type of skin lesions and the level of basal melanosis. No significant correlations were observed between the MC volume density in the lesions and any of the other items. These results suggest that the basal melanosis in a UP lesion may not be a direct reaction to the transitory massive infiltration of MC, but rather be due to a relatively long-term effect of MC infiltration. Furthermore, the MC volume density in the lesion is not likely to be an important factor in determining the clinical manifestations of a UP lesion.

Ultrastructural morphometric analysis of human mast cells in normal skin and pathological cutaneous lesions

Electron micrographs of human mast cells in normal neonatal and adult skin and in cutaneous lesions of basal cell carcinoma (BCC), hemangioma and mastocytosis were assessed by morphometric analysis. Using this quantitative histologic approach, adult skin mast cells were found to be significantly larger (47.7 microns 2 +/- 2.4 SEM vs. 38.3 microns 2 +/- 1.8 SEM, p less than or equal to 0.001) and have larger granules (0.63 micron +/- .02 SEM vs. 0.53 micron +/- .02 SEM, p less than or equal to 0.001) than infant mast cells while both mast cell populations had comparable nuclear sizes (13.7 microns 2 +/- 0.9 SEM vs. 14.3 microns 2 +/- 0.8 SEM) and numbers of cytoplasmic granules (72 +/- 4.0 SEM vs. 66 +/- 4.0 SEM). Morphometric analysis of mast cell infiltrates in the adult skin lesions of BCC and hemangioma revealed that these cells were larger than neonatal mast cells but were similar to normal adult controls. Cutaneous mast cells from 2 mastocytosis patients, however, had significantly larger mean cell surface areas (78.0 microns 2 +/- 3.4 SEM and 70.6 microns 2 +/- 3.2 SEM, p less than or equal to 0.001), nuclear areas (20.8 microns 2 +/- 1.1 SEM and 21.3 microns 2 +/- 1.2 SEM p less than or equal to 0.001) and granule diameters (0.82 micron +/- 0.4 SEM and 0.83 micron +/- .03 SEM, p less than or equal to 0.001) when compared with mast cells in normal adult skin and in the other pathologic lesions. No difference in the total number of cytoplasmic granules was observed in the different mast cell populations.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrastructural morphometric analysis of lesional skin: mast cells from patients with systemic and nonsystemic mastocytosis

Lesional skin mast cells from some patients with mastocytosis appear morphologically atypical; however, these subjective differences have not been quantified. Herein we describe an objective method for analyzing cutaneous mastocytosis mast cells by a combination of morphometric analysis and electron microscopy. By this technique, lesional mast cells from patients with adult systemic mastocytosis had a significantly larger mean cytoplasmic area (53.3 microns2), nuclear size (20.4 microns2), and granule diameter (0.81 micron) when compared with mast cells from adults with nonsystemic mastocytosis (36.3 micron 2, 15.4 microns2, and 0.67 micron, respectively) and normal age-matched control subjects (34.4 microns2, 14.1 microns2, and 0.67 micron, respectively). Lesional skin mast cells from infants with nonsytemic mastocytosis were very similar to adult nonsystemic mastocytosis mast cells but differed by several parameters from mast cells in adults with systemic involvement. This study demonstrates that there are quantitative differences between lesional skin mast cells from patients with systemic mastocytosis and those with nonsystemic disease.

Systemic mastocytosis, an unusual cause of osteoporosis

A 45-year-old patient is described presenting with severe axial osteoporosis. The presence of maculopapular skin lesions and the combination of osteolytic and osteoblastic bone lesions led to the tentative diagnosis of systemic mastocytosis. This diagnosis was confirmed by measurement of urinary histamine metabolites and by bone biopsy showing increased numbers of mast cells and fibroblast-like cells. The importance of these diagnostic procedures in this rare cause of osteoporosis is discussed.