Evaluation of HIV Type 1 Western Blot-Indeterminate Blood Donors for the Presence of Human or Bovine Retroviruses

Abstract

From 1985 through 1990, 1100 of 500,000 human blood donations in Syracuse, New York were repeatedly reactive by ELISA for antibodies to the human immunodeficiency virus type 1 (HIV-1). Nine hundred of the ELISA-reactive samples were confirmed as negative by Western blot (WB), 40 were confirmed as positive, and the remaining 160 sera were indeterminate, reacting mainly with HIV-1 gag gene products. Twenty donors with the most reactive indeterminate WB were selected for follow-up studies. Four of these 20 donors admitted to retroviral risk factors and, interestingly, 12 (60%) had exposure to dairy cattle and drank unpasteurized milk. These 20 donors were analyzed over a 3-year period for the presence of the pathogenic human retroviruses HIV-1, HIV-2, human T cell lymphoma/leukemia virus types I and II (HTLV-I and HTLV-II), as well as bovine immunodeficiency virus (BIV) and leukemia virus (BLV). Retroviral analyses included serology, plasma antigen capture, virus culture, and the polymerase chain reaction. Only one donor seroconverted and was clearly infected with HIV-1. None of the other 19 donor serological reactivities to HIV-1 changed, nor were they positive for any of the above-mentioned retroviruses. Although we cannot ascertain whether these latter 19 HIV-1 WB-indeterminate donors were exposed to human or bovine retroviral proteins, it is unlikely that their HIV-1 seroreactivity was caused by infection with HIV-1, HIV-2, HTLV-I, HTLV-II, BLV, or BIV.

Causes of false-positive HIV rapid diagnostic test results

“…However cross-reactivity, even it occurred, is likely to be in the gag region and therefore unlikely to affect HIV RDT testing. No association found between indeterminate HTLV-1, bovine immunodeficiency virus and bovine and feline leukemia virus WBs and false positive immunoassay results in two reports [14,101]. …”

Prevalence of HTLV-I-associated T-cell lymphoma

“…A sample was deemed to be a confirmed positive if reactivity was observed against HTLV gag p24 and HTLV-I or II surface envelope protein gp46 or their pre-cursor gp68 [16]. All HIV repeatedly reactive samples were confirmed in a HIV-1 Western blot assay, with reactivity to HIV-1 gag p24 and gp41 and/or gp120 env being deemed seropositive [17].…”

“…All the above DNAs were analyzed via the polymerase chain reaction (PCR) for human ␤-globin using the primers PCO 3 and PCO 4 and for the presence of either HTLV-I or HTLV-II using the HTLV-I/II pol primers SK110 and SK111, the HTLV-I-specific probe SK112, and the HTLV-II-specific probe SK188 as previously described [4,18] or for the presence of HIV-1 gag using the primers SK38 and SK39 and the probe SK19 and for the presence of HIV-2 LTR using the primers SK89 and SK90 and the probe SK91 as previously described [17]. Undigested or EcoR1-, BamH1-, and/or HindIII-digested tumor specimen DNAs from the HTLV-or HIV-positive lymphoma patients were also analyzed for HTLV-I or for HTLV-II DNA and T-cell receptor gene or immunoglobulin gene rearrangements via Southern blot hybridization as previously described [4,19].…”

Communicating Indeterminate HIV Western Blot Test Results to Clients: An Observational Study of Three Community Testing Sites

“…8 Third, the indeterminate test result may be a false-positive and not be associated at all with HIV infection. 9 Possible reasons for a false-positive HIV test result include: (1) prior blood transfusions, (2) prior or current infection with syphilis, (3) prior or current infection with malaria parasites, 10,11 (4) autoimmune disease such as diabetes, (5) association with large animals, for example through veterinary work, [12][13][14] and (6) second or subsequent pregnancies in women. 12 Indeterminate results from multiple blood transfusions, syphilis, autoimmune diseases, and multiparity may be caused by autoantibodies, particularly anti-major histocompatibility complex (MHC) antibodies that may cross-react with glycoproteins or HIV proteins.…”