Suppression of phytohemagglutinin response by fungi from a "leukemia" house.

Fungal isolates from the house of a husband and wife who both developed acute myelomonocytic leukemia were assayed for effects on the in vivo response to phytohemagglutinin in guinea pigs. Skin responses to intradermal phytohemagglutinin were measured following injections of sterile fungal extracts. Isolates of Penicillium canescens, Curvularia, Fusarium sambucinum, Fusarium equiseti and Trichoderma koningii from the leukemia-associated house depressed the responses to phytohemagglutinin, but none of the fungal isolates obtained from a nearby control house depressed responses to phytohemagglutinin. Such environmental agents may contribute to development of malignancy by suppression of immune responses.