Developmental immunotoxicity of cyclosporin-A in rats: age-associated differential effects

Cyclosporin-A (CYP-A) is a widely used immunosuppressive drug. Yet, information on the long-term impact of embryonic exposure is relatively scarce. The effects of CYP-A on reproductive and immunologic parameters in CD strain female offspring exposed in utero at doses of 0, 0.2, 2, 10, or 20 mg/kg/day (from gestational day 6 to 21) were compared against identically dosed CD adult rats. Embryotoxicity was seen at the two highest doses. CYP-A was acutely immunotoxic in adults (tested at 20 mg/kg/day dose) but with minimum long-term effects. In contrast, the offspring experienced relatively persistent alterations. CYP-A exposure increased ano-genital distance in the neonates. In the 5-week-old offspring, the delayed type hypersensitivity (DTH) response and splenic B cell number (determined by flow cytometry) were both decreased at the 2 mg dose level. IL-4 level was reduced and blood monocytes were increased at both exposure doses. All other parameters were unchanged. In the adult offspring (13-week-old), no difference was seen in either the DTH response or B cell ratios, but IL-4 level was increased at 2 mg/kg/day, and anti-KLH IgG titer decreased at both doses. In exposed non-pregnant adults, changes were minimal following a 13-week recovery period. Blood neutrophils were increased at all doses of the drug and flow cytometry data suggested some perturbation in CD4+CD8+ cells, macrophages, and B-cells. All other parameters were unchanged. In conclusion, the adult rodent immune system largely recovers from CYP-A exposure given sufficient time. However, embryonic exposure appears to produce a series of immune perturbations including functional impairment during postnatal maturation.