CD4 and infection: Furthermore, calcitriol treatment exhibited a more potent effect on decreasing infection of CD4+ T cells with a more infective R5 (Bal) HIV-1 strain in our Canadian cohort, with a reduction between 57% and 67% observed for both concentrations of this hormone, compared to EtOH (p = 0.0018 and p = 0.0068) (Fig 1D).