GB virus C infection and survival in the Amsterdam Cohort Study.

eterious effect that the loss of GBV-C infection without the accompanying development of GBV-C envelope protein–2 antibodies has on survival, which was observed by others [4, 6]. This again confirms that persistent GBV-C infection is beneficial. Van der Bij et al. are to be commended for examining the effect that GBV-C acquisition has after HIV-1 seroconversion; previous studies have not included enough patients who had acquired the infection after seroconversion to allow for evaluation of this issue. Again, however, Van der Bij et al. show in table 3 that there is a statistically significant beneficial effect of GBV-C acquisition on the HR of first CD4 cell count !200 cells/mL (HR, 0.34, 0.33, and 0.52), AIDS (HR, 0.56, 0.74, and 0.79), and death (HR, 0.35, 0.53, and 0.44) in models 1, 2, and 3, respectively, and progression from AIDS to death in model 1 (HR, 0.56). In summary, contrary to Van der Bij et al.’s interpretation, the ACS does show that persistent GBV-C infection has a beneficial effect on HIV-1 disease progression—in accordance with the results of other studies—when the effect is not adjusted for causal variables associated with GBV-C infection, which is statistically invalid [2]. The results of Van der Bij et al.’s study also confirm previous findings regarding the deleterious effect that the loss of GBV-C infection has, and it is the first study to show that GBV-C acquisition has a statistically significant benefit after HIV1 seroconversion has occurred.