Anaphylaxis with clonal mast cells in normal looking skin - a new entity?

BACKGROUND: Patients with elevated basal tryptase (sBT) >15 µg/l and anaphylaxis may have an underlying mastocytosis. A monoclonal mast cell activation syndrome with aberrant mast cells (MC) at extracutaneous sites has been described in patients with severe hypotension or anaphylaxis. METHODS: As MC in patients with elevated sBT might be altered in the skin as well, we studied MC in normal neck skin in anaphylaxis and urticaria patients with elevated sBT. RESULTS: A mean of 93.1 (SD 19.1) MC/mm² was counted in normal neck skin in 14 patients with anaphylaxis, 84.0 (SD 13.6) in seven patients with urticaria, 142.0 (SD 24.0) in two patients with eczema, 124.4 (SD 43.2) in five patients with systemic mastocytosis (SM) in comparison with autopsy skin (39.1 MC/mm², SD 12.4). In five of 14 (35.7%) of the anaphylaxis and three of five (60%) SM patients more than 25% of MC were spindle shaped and expressed CD25 antigen. CONCLUSIONS: We could show for the first time that the normal skin can harbour clonal MC in anaphylaxis patients. Analogous to the criteria for mastocytosis, we suggest a skin score criteria including an elevated number of MC, spindle shape, CD25 expression, c-Kit mutation and sBT values >20 µg/l. In patients with anaphylaxis and elevated sBT, skin should be biopsied and, as with the approach for mastocytosis diagnosis in the bone marrow, MC should be analysed for their number, clonality and c-Kit mutation. This approach should be confirmed in further studies. Patients with aberrant skin MC should be handled as mastocytosis patients.

Treatment with 311-nm ultraviolet B accelerates and improves the clearance of psoriatic lesions in patients treated with etanercept.

BACKGROUND: Some patients with plaque-type psoriasis respond slowly to treatment with etanercept. In such cases combining etanercept with conventional treatments might be helpful. OBJECTIVES: To investigate whether treatment with 311-nm ultraviolet (UV) B can improve the therapeutic response in patients treated with etanercept. METHODS: Four women and one man (mean age 57 years, range 48-66) with moderate to severe plaque-type psoriasis who had received standard treatment with etanercept 50 mg twice weekly for 6 weeks without Psoriasis Area and Severity Index (PASI) reduction of 75% or greater (of initial mean PASI of 16.0, range 15.4-20.4) were enrolled in the study. Starting at 6 weeks, 311-nm UVB treatment was given to a randomly selected body half (left or right, excluding the head) for another 6 weeks, while all patients continued receiving etanercept. The patients were monitored by half-body PASI at weekly intervals. RESULTS: During the 6-week irradiation regimen, 311-nm UVB significantly bolstered the therapeutic response in the patients on etanercept treatment. After 6 weeks of 311-nm UVB, the patients had a mean PASI on their UV-irradiated body halves of 1.6 (range 0.6-3.3) vs. 4.7 (range 1.4-8.6) on nonirradiated body halves (P = 0.0192, paired two-tailed t-test), compared with 10.7 (range 6-16.4) and 10.5 (range 5.2-16.4) at start of 311-nm UVB treatment. The overall mean PASI reduction from baseline (i.e. at etanercept start) was 89% vs. 68%, respectively (P = 0.0009 and P = 0.0088). CONCLUSIONS: Treatment with 311-nm UVB significantly accelerates and improves the clearance of psoriatic lesions in patients responding slowly to etanercept monotherapy.