In situ characterization and counting of mononuclear cells in lesions of different clinical forms of psoriasis.

Mononuclear cells in the dermis were characterized and counted in cryostat sections of lesional skin from 34 patients with various clinical forms of psoriasis. T lymphocytes were detected with F(ab')2 preparation of rabbit IgG against human T lymphocytes and acid alpha-naphthyl acetate esterase (ANAE) activity as histochemical marker. The ANAE method was also used for the detection of macrophages. Comparable results were obtained using both the anti-T lymphocyte serum method and the ANAE method. The highest proportion of ANAE-positive lymphocytes was found in sections from stationary lesions of psoriasis vulgaris (61.2%), and the lowest in lesions of erythroderma (38.5%). ANAE-positive macrophages constituted 51.3% of the mononuclear cells in lesions of erythroderma and 29.7% in stationary lesions of psoriasis vulgaris. Only a few B lymphocytes could be detected with goat antibodies against human Fab of Ig. Cells with receptors for the Fc part of IgG (FcR) were detected using soluble complexes of horseradish peroxidase (HRP-anti-HRP. Most FcR-positive cells were found in lesions of pustular psoriasis (53.7%) and in erythroderma (45.5%), and fewest (18.3%) in stationary lesions of psoriasis vulgaris.