Evidence of Serological Cross-Reactivities with Human Immunodeficiency Virus Types 1 and 2 and Human T-Lymphotropic Virus Types I and II in Sera of Pregnant Women in Ibadan, Nigeria

The authors previous studies have indicated that the human immunodeficiency virus (HIV) and human T-lymphotropic virus (HTLV) groups of retroviruses are endemic among various populations in Nigeria. These viruses are antigenically distinct and antibodies to HIV and HTLV do not cross-react so the authors studied the prevalence of HIV-1 HIV-2 HTLV-I and HTLV-II antibodies in sera of pregnant women attending an antenatal clinic in Ibadan Nigeria. In all 364 sera were screened using 3 different enzyme immunoassays including those that distinguished HIV-1 antibodies from HIV-2 and HTLV-I antibodies from HTLV-II. All repeatedly reactive sera were confirmed by Western blots and synthetic peptide assays for the respective viruses. Overall 71 sera (19.5%) had antibodies to HIV HTLV or both groups of retroviruses. Most (95.8%) of the reactive samples were from women 20-29 years old. Two of 5 sera from individuals <20 years old reacted for HIV antibodies while 1 serum from a 40-year-old woman was reactive for HTLV-I antibodies. Of the 71 reactive sera 29 (8%) had antibodies to HIV (HIV-1 = 14 HIV-2 = 9 HIV-1/2 = 6) and 42 samples (11.5%) showed antibodies to HTLV (HTLV-I = 20 HTLV-II = 14 HTLV-I/II = 8). Seven of 71 seropositive samples (9.8%) reacted for both HIV and HTLV antibodies in various combinations including 1 serum that showed antibody reactivities to all 4 retroviruses (i.e. HIV-1 HIV-2 HTLV-I and HTLV-II). The high prevalence of antibodies to subtypes of the 2 entirely distinct retrovirus groups in young women has important implications for defining epidemiological patterns of diseases associated with co-infections with 2 or more retroviruses. (authors)