CD4 and coinfection: We were surprised to find this association in the setting of HIV-HBV co-infection given our previous work showing that in HIV-HBV co-infected patients not receiving HAART, a lower CD4 count was associated with a lower number of HBV-specific T-cells [35] and that there was little increase in HBV-specific T-cells in the first 48 weeks following HBV-active HAART [11].