HIV-1/2 indeterminate Western blot results: follow-up of asymptomatic blood donors in Belo Horizonte, Minas Gerais, Brazil

Abstract

The clinical and public health importance of indeterminate results in HIV-(1/2) testing is still difficult to evaluate in volunteer blood donors. At Fundacao Hemominas, HIV-(1/2) ELISA is used as the screening test and, if reactive, is followed by Western blot (WB). We have evaluated 84 blood donors who had repeatedly reactive ELISA tests for HIV-(1/2), but indeterminate WB results. Sixteen of the 84 donors (19.0%) had history of sexually transmitted diseases; 18/84 (21.4%) informed receiving or paying for sex; 3/84 (3.6%) had homosexual contact; 2/26 women (7.6%) had past history of multiple illegal abortions and 3/84 (3.6%) had been previously transfused. Four out of 62 donors (6.5%) had positive anti-nuclear factor (Hep2), with titles up to 1:640. Parasitological examination of the stool revealed eggs of S. mansoni in 4/62 (6.4%) donors and other parasites in 8/62 (12.9%). Five (5.9%) of the subjects presented overt seroconversion for HIV-(1/2), 43/84 (51.2%) had negative results on the last visit, while 36/84 (42.9%) remained WB indeterminate. Although some conditions could be found associated with the HIV-(1/2) indeterminate WB results and many donors had past of risky behavior, the significance of the majority of the results remains to be determined.

Frequency, Causes, and New Challenges of Indeterminate Results in Western Blot Confirmatory Testing for Antibodies to Human Immunodeficiency Virus

“…Notably, the band for reactivity to p24 viral protein was the most frequently occurring band among all the WBi patterns regardless of cohorts or study settings (5,10,96). Studying 84 blood donors with repeated indeterminate results, Carneiro-Proietti et al (10) obtained a frequency for the anti-p24 band of 91.6%.…”

“…Notably, the band for reactivity to p24 viral protein was the most frequently occurring band among all the WBi patterns regardless of cohorts or study settings (5,10,96). Studying 84 blood donors with repeated indeterminate results, Carneiro-Proietti et al (10) obtained a frequency for the anti-p24 band of 91.6%. Although this was found at a more moderate level of 74% in a separate study of Urnovitz et al (96), the anti-p24 band remained predominant among all the other antiviral markers, with the next highest reaching only 16% for an HIV-1 low-risk group.…”

HIV Diagnosis in Resource Constrained Setting: How Good Is the Current Algorithm?

“…Notably, the band for reactivity to p24 viral protein has been reported to be the most frequently occurring band among all the WBi patterns regardless of cohorts or study settings [23] [32] [33]. One of the possible suggested reasons for this could be that, the auto antibodies cross reacting with p24 are seen in autoimmune diseases like SLE [20] [21].…”

HIV serologically indeterminate individuals: Future HIV status and risk factors

“…Celum et al reports that among males, tetanus boosters in the previous two years and having sexual contact with prostitutes were independently associated with HIV indeterminate results; and among females, parity and autoantibodies were independently associated with indeterminate results [11]. HIV indeterminate results have also been associated with systematic lupus erythematosus, rheumatoid factor and polyclonal gammopathy, antibodies to DR-HLA, cross reactivity to core proteins of other retroviruses, mycobacterium leprae infection, heat inactivation of serum samples, in vitro hemolysis, elevated bilirubin levels and tetanus vaccination [12]. An HIV indeterminate result may be associated with acute HIV infection [13][14][15], and WHO recommends that such an outcome among high risk populations or those with a history of high risk behaviors should be considered as a potential case of acute HIV infection [16].…”

“…Other studies report serologically indeterminate prevalence below 6% [6,8,17]. However, it is challenging to project future outcomes from existing studies of HIV indeterminate results due to small sample sizes [12][13][14] and short follow-up time (less than a year) [8,11,18]. Understanding the correlates of ELISA indeterminate results may help HIV surveillance programs to select the appropriate tests and to develop a protocol on how to handle individuals with ELISA indeterminate results.…”