Cutaneous and systemic mastocytosis in adults. A clinical, histopathological and immunological evaluation in relation to histamine metabolism.

At the Department of Dermatology, Sahlgrenska sjukhuset, Göteborg, 58 patients with mastocytosis were investigated during the years 1979-1984. The purpose of this study was to examine the extent of the disease, the degree of mast cell infiltration in skin and bone marrow, to evaluate the most frequently used diagnostic methods, to study some immunological functions and genetic markers, to determine the histamine metabolism and to test a new drug which inhibits histidine decarboxylation. Besides a clinical examination, skin biopsies were taken from involved and uninvolved skin. The biopsies were fixed in 4% neutral formaldehyde or in an iso-osmotic mixture of 0.6% formaldehyde and 0.5% acetic acid (IFAA) and stained with toluidine blue 30 minutes or 5 days. The mast cell density in the formaldehyde fixed biopsies stained 5 days was significantly higher than the routine short stained biopsies. The same results were obtained with IFAA fixation and short toluidine stain. This might be caused by aldehyde blocking of dye-binding groups, which has been observed earlier in mucosal mast cells. Sternal aspirate and crista iliaca biopsies were done in order to examine the bone marrow. When comparing these two methods, the bone-marrow biopsy was found to be more reliable and sensitive when judging the mast cell increase. This resulted in more systemic mastocytosis patients being detected through crista biopsy than through sternal aspirate. Lesions with mast cells, eosinophils and lymphocytes were seen in the biopsies. These lesions may be an early sign of a systemic involvement of the disease. The urinary tele-methylimidazoleacetic acid (MeImAA) excretion was increased in most of the patients, and was found to correlate with the extent of the disease, both concerning organs involved and the mast cell numbers in the bone marrow. A lymphocyte stimulation with Concanavalin-A (Con-A) and phytohaemagglutinin (PHA) showed a decreased mitogenic response, especially in the patients with the highest histamine turnover. Inhibition was also seen when histamine was added to mitogen stimulated lymphocytes from healthy controls, while only a minimal inhibition of the mitogen response was obtained by histamine metabolites. Even if histamine in vitro seems to affect the lymphocyte mitogenic response, and the lymphocyte stimulation in the patients was inhibited, this does not seem to have any obvious clinical relevance. HLA-typing was carried out on 50 patients but no phenotypic aberrations were detected. Lymphocytes from patients with HLA-B12 seemed to react with the same mitogenic inhibition as those from other patients.(ABSTRACT TRUNCATED AT 400 WORDS)