Lack of In Vitro Antimicrosporidian Activity of Thalidomide

Thalidomide was evaluated for its in vitro activity against Encephalitozoon species by using the MRC-5 cell system. A cytotoxic effect was observed for concentrations of 10(1) μg/ml (P < 10(5)) and 5 μg/ml (P < 10(5)). Thalidomide did not significantly inhibit the growth of any of the microsporidia under study. These data suggest that thalidomide is not an etiologic treatment in microsporidial enteritis.