| ||||||
Confounding
Positive HIV tests are more commonly found in sick people. The most common interpretation of this is that the tests identify HIV, which is the virus making them sick. Another interpretation is that other conditions can produce antibodies that may register false positive on HIV tests. Without a gold standard, we will never know.
“Natural antibodies (NAb) are those that are present in the serum of healthy individuals in the absence of deliberate immunization with the target antigen. The importance of NAb reactive with self-antigens has long been neglected…However, it is now well established that autoreactive antibodies and B and T cells are present in healthy individuals, and that autoreactive repertoires are predominantly selected during fetal life [Consider what would happen if some of these naturally occurring ‘polyreactive’ antibodies reacted with the HIV proteins in an HIV antibody test! Yes, you would have a false positive.]”
Varambally S et al. Natural human polyreactive IgM induce apoptosis of lymphoid cell lines and human peripheral blood mononuclear cells. Int Immunol. 2004 Mar;16(3):517-524.
“An association was noted between the presence of red blood cells in CVL [Cervico-Vaginal Lavage] and HIV-1 shedding [i.e. detection of RNA believed to be diagnostic for HIV in the cervix/vagina]”
Kovacs A et al. Determinants of HIV-1 shedding in the genital tract of women. Lancet. 2001 Nov 10;358(9293):1593-1601.
“Data from studies conducted in Africa have shown an association between Trichomonas [a vaginal parasite] and HIV infection, suggesting a two- to threefold increase in HIV transmission[4,13,14]. A cross-sectional study conducted among 1,209 female sex workers in the Ivory Coast found an association between HIV and Trichomonas infection in bivariate analysis (crude odds ratio 1.8, 95% confidence intervals 1.3, 2.7). In another cross-sectional study performed in Tanzania among 359 women admitted to a hospital for gynecologic conditions, Trichomonas was more common in women with HIV infection in multivariate analysis (odds ratio 2.96, no confidence intervals provided, p<0.001). While such cross-sectional studies are limited by the issue of temporal ambiguity, i.e., lack of information on whether Trichomonas infection preceded HIV, these preliminary findings were subsequently reinforced in a single prospective study from Zaire[4]. This study, in which 431 HIV-negative female prostitutes were evaluated over time, found that prior Trichomonas infection was associated with a twofold increased rate of HIV seroconversion in muiltivariate analysis. [The authors did not consider the possibility that this infection could result in the production of antibodies that cause cross-reactions on HIV tests, and do not actually indicate an HIV infection]
”
Sorvillo F et al. Trichomonas vaginalis, HIV, and African-Americans. Emerg Infect Dis. 2001;7(6):927-32.
http://womenshealth.medscape.com/govmt/CDC/EID/2001/v07.n06/e0706.03.sorv/mig-pnt-e0706.03.sorv.html
http://womenshealth.medscape.com/govmt/CDC/EID/2001/v07.n06/e0706.03.sorv/mig-pnt-e0706.03.sorv.html
“HSV-2 [Herpes Simplex Virus-2] seropositivity was a strong independent risk factor for HIV infection with odds ratios of 5.3 for men and 8.4 for women [Another interpretation is that a high level of antibodies makes a (false) positive HIV test more likely]”
Auvert B et al. HIV infection among youth in a South African mining town is associated with herpes simplex virus-2 seropositivity and sexual behaviour. AIDS. 2001;15(7):885-98.