In vivo effects of PUVA on lymphocytes function.

Whole-body exposure to erythemogenic doses of PUVA in normal volunteer subjects resulted in a decrease in the proportion of circulating sheep erythrocyte rosette-forming and surface membrane immunoglobulin-positive lymphocytes and an increase in the proportion of null cells. Doses of PUVA resulting in minimal or no erythema had similar but less marked effects on lymphocytes. The changes appeared 30 min after exposure, were maximal at 12-16 h and returned to pre-treatment levels by 72 h post-irradiation. The response of lymphocytes to stimulation with phytohaemagglutinin was unaffected. No alteration occurred in the absolute numbers of circulating lymphocytes or polymorphonuclear leukocytes.