The possible role of fungal infections in AIDS.

The acquired immunodefficiency syndrome (AIDS) is characterized by a gross defect in the cell-mediated immune response. However, infection with human immunodeficiency virus (HIV), which is the generally accepted etiological factor of AIDS, cannot explain by itself the following problems: why do not some of the seropositive subjects develop AIDS or AIDS-related complex; why are some of the patients with AIDS seronegative for HIV and its corresponding antibodies; what is the reason why some of the healthy seronegative subjects from groups at a high risk for AIDS (homosexuals, hemophiliacs and drug abusers) have low T-helper to T-suppressor ratios. We suggest that some additional factor is necessary for the development of AIDS. We propose that the factor needed is a 'partial functional thymectomy'. We suspect that slow fungal infections, producing thymotoxic metabolites, may be a major cause for the latter.