Background:  Recent reports suggest that GBV-C co-infection leads to longer survival and slower progression for HIV disease. We were interested in assessing whether acute GBV-C infection following blood transfusion is related to lower HIV viral loads and higher CD4 counts, consistent with a mechanism of action for GBV-C on HIV through direct or indirect viral interference.

Methods:  The Viral Activation Transfusion Study (VATS) followed HIV-infected, transfusion-naïve persons requiring transfusion. Pre-transfusion and post-transfusion blood samples were tested for markers of HIV disease progression, and subsequently for GBV-C RNA and antibody (quantitative GBV-RNA RT-PCR, anti-GBenv uplate EIA; Roche Diagnostics). The dataset contains longitudinal information with laboratory measures before transfusion and at least one set of measures during follow-up for 405 subjects. We report adjusted mean HIV viral load and CD4 counts controlling for within subject correlation and differing lengths of the follow-up between subjects using generalized estimating equations for panel data.

Results:  The table provides mean HIV viral load and CD4 counts stratified by GBV RNA and HAART. Although there is variability, as evidenced by the confidence intervals, the mean values suggest that persons who are presumed to have acquired GBV-C co-infection via transfusion have decreased viral loads and increased CD4 counts. Within appropriate comparison categories of HAART (on HAART or not on HAART) persons who never tested positive for GBV-C RNA had higher viral loads and lower CD4 counts.

*controlling for within subject correlation and days since transfusion

Conclusions:  These results support recent articles suggesting slower disease progression in individuals co-infected with GBV compared with individuals who are GBV RNA negative, regardless of HAART. We are currently analyzing the entire longitudinal dataset containing multiple post-transfusion observations on each subject for changes in viral load and CD4 in relation to GBV and HAART over the 3.5 year VATS follow-up period, particularly for the 38 cases who converted from GBV RNA negative to positive.

Keywords: GBV-C; HIV; HAART