Increased detection of HBV DNA in HBsAg‐positive and HBsAg‐negative South African HIV/AIDS patients enrolling for highly active antiretroviral therapy at a Tertiary Hospital

This retrospective study investigated the prevalence of hepatitis B virus (HBV) in 192 stored sera from human immunodeficiency virus (HIV) positive South African patients initiating antiretroviral therapy (ART), and explored the implications of HBV–HIV co‐infection on laboratory diagnosis of HBV. HBV serology (HBsAg, anti‐HBs and anti‐HBc) and nested HBV PCR assays targeting the HBV polymerase gene were performed, with HBV DNA positive samples being quantified with Cobas Taqman HBV test 48 assay (Roche Diagnostics). The study found that 63% (121/192) of patients had past or present HBV infection, and 40.6% (78/192) had detectable HBV DNA. Also, 22.9% (44/192) of patients were HBsAg positive and HBV DNA positive, while 23% (34/148) of HBsAG negatives had occult HBV infections. Of the 78 HBV DNA positive samples, 62.8% had viral loads ranging from 10² to ≥10⁸ IU/ml, and 37.2% had HBV viral loads <200 IU/ml. There was a statistically significant positive association between HBsAg‐positivity and high viral loads, with 27% (12/44) of HBsAg positives having HBV viral loads between 10⁴ and ≥10⁸ IU/ml, compared to only 5.9% (2/34) of HBsAg negatives (relative risk: 4.64; 95% confidence interval: 1.11, 19.35; chi‐square P‐value = 0.015). The study shows that the majority of HIV/AIDS patients initiating ART have either acute or chronic HBV infections, and further confirms that HIV remains a risk factor for occult HBV infections in South African patients as previously shown. The findings strongly support HBV screening in all HIV‐positive patients initiating ART in South Africa, considering that current ART regimens include drugs with anti‐HBV activity (e.g., lamivudine). J. Med. Virol. 81:406–412, 2009. © 2009 Wiley‐Liss, Inc.     

High risk of occult hepatitis B virus infection in HIV-positive patients from South Africa.

This was a retrospective, unmatched case control, laboratory-based study, investigating the impact of human immunodeficiency virus (HIV) infection on the outcome of routine laboratory detection of HBsAg and prevalence of active HBV infection in 295 samples from 167 HIV-positive and 128 HIV-negative patients. The samples were tested for HBV (HBsAg, anti-HBc, anti-HBs, HBeAg and anti-HBe) and anti-HIV 1 and 2 (Axsym assays, Abbott Laboratories), as part of routine diagnosis. A nested PCR assay, with detection limit of 800 copies/ml and employing independent sets of primers to core and surface genes, was used to investigate HBV DNA. Quantification of HBV DNA was determined with the Cobas Amplicor HBV Monitor assay (Roche Diagnostics). Of the 295 samples, the frequency of anti-HBc was almost similar; 82% for the HIV-negatives and 85% for the HIV-positives, indicating that both groups were equally exposed to HBV infection. The HIV-positives had a higher rate of anti-HBs (76.0% versus 47.7%) and a lower rate of HBsAg carriage (16.2% versus 35.2%), suggesting that HIV-positive individuals are less likely to experience chronic HBV infection. However, analysis of HBV DNA indicated that many of the anti-HBs positives (20.5% versus 8.2%) and HBsAg-negatives (22.1% versus 2.4%) had active HBV infection in the HIV-positive group. There was a statistically significant difference in the prevalence of HBV DNA in the HBsAg-negatives between the two groups (Odds ratio: 11.52; chi-square: p=0.00006). Additionally, 33.3% (5/15) of sera with "anti-HBc alone" serological pattern were HBV viremic in the HIV-positive group, compared to 0% (n=31) in the HIV-negatives. Quantification of HBV DNA from HBsAg-negative/HIV-positive patients demonstrated low level HBV viremia (below 10,000 copies/ml). In conclusion, these findings strongly support that HIV infection is a risk factor for occult HBV infections.     

Genetic characterization of HIV before widespread testing of HIV vaccine candidates at a clinical trial site in Pretoria, South Africa

We studied 123 samples from adult chronic HIV patients initiating HAART from various centers around a newly established clinical trial site in Pretoria. Each sample was sequenced in at least one structural gene (pol, gag, and env) or functional gene (vif, vpr, and vpu). A subset of 25 samples was subjected to near full-genome analysis. All samples were HIV-1 subtype C. Highly conserved regions within the gene sequences were observed. Overall, the gag and vif sequences showed closer similarity followed by the env, vpr, pol, and vpu. The env gene was the most difficult to sequence, resulting in only 31 sequences from 40 samples; of these, 25 were predicted to be R5 coreceptor tropic, while 6 were X4 tropic. The study asserted the predominance of HIV-1 subtype C within the catchment population.