Histamine release from skin mast cells and basophils in patients with urticaria pigmentosa

Histamine release from dispersed skin mast cells may be used for functional studies on the mast cell. However, technical difficulties have hampered such studies. In the present study a new fiberglass-based histamine assay was applied to previously described dispersion techniques, using excision biopsies from 7 patients with urticaria pigmentosa, 3 with psoriasis as well as 4 with urticaria. However, sufficient mast cell numbers for performing histamine release could only be obtained from patients with urticaria pigmentosa. The average mast cell yield was 935 +/- 470 cells (mean +/- SD) per mg wet weight of tissue. The skin mast cells from these patients responded with dose-dependent histamine release to anti-IgE, calcium ionophore A23187, and N-formyl-methionyl-leucyl-phenylalanine challenge without previous passive sensitization. The pattern of histamine release of mast cells and corresponding blood basophils did not indicate substantial differences between the two cell types.