Suppressive effects of two bioresponse modifiers, krestin and levamisole, on 5-azacytidine-induced digital defects in rats.

The effects of two bioresponse modifiers, krestin (PSK) and levamisole hydrochloride (levamisole), on 5-azacytidine (5-AC)-induced syndactyly, brachydactyly, and ectrodactyly were investigated. Both PSK and levamisole suppressed 5-AC-induced digital malformation in the rat. The effect of PSK was significant when given 24 h before to 1 h after 5-AC treatment, and levamisole when given 12 h before to 3 h after treatment. Both agents showed an immune-stimulating effect and have been used as cancer chemotherapeutic drugs. However, as the contribution of fetal or maternal immune functions or the alleviation action is unknown, further investigations are required to clarify the mechanism.