Langerhans' cells in patients with psoriasis: effect of treatment with PUVA, PUVA bath, etretinate and anthralin.

Suction blisters were raised in lesions and normal appearing skin of patients with psoriasis. The blister roof which contains the epidermis separated at the dermal-epidermal junction was stained with ATPase, OKT-6 and anti-HLA-DR monoclonal antibodies. The technique permits the counting of the Langerhans' cells per mm2. Their mean number varied between 888-987 cells per mm2 in control subjects with the three staining procedures. In patients with psoriasis, the number of cells before treatment was between 1110-1179 in uninvolved skin and 521-1001 per mm2 in the lesions as measured using both monoclonal antibodies and ATPase. However, the latter technique seemed to be inappropriate for lesional skin. After treatment with PUVA bath or oral PUVA with or without etretinate, fewer Langerhans' cells were seen in both lesions and normal appearing skin with the appearance of giant Langerhans' cells with long dendrites. In patients healed with anthralin + UV-B the Langerhans' cells appeared normal in number and size.