LYMPHOCYTE-T E-ROSETTE FUNCTION DURING PHOTOCHEMOTHERAPY (PUVA) OF PSORIASIS

E rosette formation by peripheral blood T lymphocytes was studied during photochemotherapy (PUVA) of psoriasis. Prior to PUVA treatment the percentage of E rosette forming cells was found to be markedly decreased in patients with active psoriasis, whereas it was normal in those with inactive skin lesions. In the initial phase of PUVA therapy (within the first 2 weeks) single PUVA exposure induced the decrease of the percentage of E rosettes in patients with psoriasis, but not in normal controls. This immediate suppression of E rosette formation, which persisted for more than 24 hr, was related to combined 8 MOP + UVA action, but not to 8 MOP or UVA irradiation alone. T lymphocytes reacquired an initial number of E rosette forming cells 48 hr after the last PUVA exposure. PUVA-induced inhibition of E rosette formation was most prominent in patients with inactive psoriasis in whom the initial percentage of E rosettes before treatment was normal. A lesser degree of decrease of E rosette forming cells after PUVA exposure was observed in patients with active psoriasis and reduced initial percentage of E rosettes. The suppression of E rosette formation caused by PUVA exposure was related to the presence of psoriatic lesions, since it could not be demonstrated after clearing of skin changes. Irrespective of preceding activity of the disease, E rosette formation showed a gradual improvement with PUVA therapy. The reduction in the percentage of E rosettes completely disappeared in the fourth week of PUVA treatment, which was correlated with healing of skin lesions. Almost all patients with psoriasis (85%) recovered normal E rosette function up to 1 mo after termination of PUVA treatment.