[Deleterious effect of levamisole on experimental trypanosomiasis in mice].

One outbred strain, NMRI, and 4 inbred strains of mice, BALB/c A/J, CBA and C57B1/6, of widely differing susceptibilities to infection by Trypanosoma (Nannomonas) congolense, stock Dinderesso/80/CRTA/3, were treated throughout the course of infection with levamisole, an immunomodulating drug. Under the regime used this drug is capable of restoring depressed immune responses. Surprisingly, levamisole was not beneficial to the course of infection. In all of the strains except BALB/c, levamisole treatment increased mortality and in three of the strains parasitaemia was enhanced. The authors discuss possible reason for these findings which highlight the fact that the protective immune mechanisms operating in African trypanosomiasis are still poorly understood.