Serological cross-reactivities between the retroviruses HIV and HTLV-1 and the malaria parasite Plasmodium falciparum.

Serum samples from three populations of Papua New Guinea, where Plasmodium falciparum malaria and human T-lymphotropic virus type 1 (HTLV-1) are coendemic at high prevalence rates, showed statistically significant ELISA co-seropositivity and co-seronegativity. Cross-reactivity was further indicated by the presence of 10 bands ranging from 134 kDa to 18 kDa on immunoblots of electrophoresed whole lysate P. falciparum antigen against serum of HTLV-1 seropositive patients from an area where malaria is not present. Similarly, sera from patients positive for human immunodeficiency virus (HIV) from a non-malarious region produced immunoblot bands ranging from 134 kDa to 33 kDa to the P. falciparum antigen. The HTLV-1 and HIV serum samples yielded a number of immunoblot bands when reacted to an electrophoresed human O type red cell membrane antigen, but those bands had no identity to the cross-reactive bands on the P. falciparum antigen immunoblots. Malaria-positive sera from Papua New Guinean subjects presumed to be uninfected with HIV produced a variety of bands, some of intense prominence, to HIV antigen on diagnostic Western blots.