The effect of photochemotherapy (PUVA) on cell mediated immunity in the guinea pig

Guinea pigs were injected intraperitoneally with 8-methoxypsoralen (8-MOP) and afterwards the shaved right flank was irradiated with UV-A. This treatment was performed daily for 14 days. Seven days after treatment started they were immunized with ovalbumin in Freund's complete adjuvant and 7 days later skin tested with ovalbumin on the unirradiated left flank. Photochemotherapy (8-MOP plus UV-A) did not alter the total white blood cells or the proportion of lymphocytes or granulocytes. However, this treatment significantly depressed the delayed hypersensitivity reaction to ovalbumin; nonspecific inflammation, induced by intradermal turpentine, was not altered. In addition, treatment with 8-MOP alone suppressed the skin reaction to ovalbumin, but not to the same extent as treatment with 8-MOP and UV-A. 8-MOP plus UV-A had no effect on macrophage migration inhibition factor but it did significantly depress mitogen and antigen specific lymphocyte transformation.