Suppression of the allergic contact reaction in the guinea pig by cyclosporin A.

In a study of the effects of cyclosporin A on the allergic contact reaction to oxazolone in the guinea pig, a pronounced ability to suppress redness and edema and the dermal inflammatory cell infiltrate was demonstrated. At the generally recommended (human) organ transplantation immunosuppression dosage (20 mg/kg), a single dose gave no certain effect, but when repeated daily for 3 days, some suppression of the reaction was seen. A single 80 mg/kg dose produced marked suppression of erythema and edema and all components of the dermal cellular infiltrate. This effect was still evident, though less marked, 3 days after administration. The 80 mg/kg dose had no effect on the toxic contact reaction to croton oil. Of the agents we have previously tested (cyclophosphamide, methotrexate and azathioprine) with this model, cyclosporin A has by far the most marked capacity to suppress the allergic (cell-mediated) contact reaction, via a mechanism which would appear to involve immunomodulation rather than mere nonspecific anti-inflammatory effects.