CD40LG and cytomegalovirus infection: According to these data, a correlation between IgG antibody levels and the frequencies of apoptosis-prone CD4+ and CD8+ T-cells and increased total cell death, apoptosis and necrosis in CD4+ T-cells from CMV IgM+ individuals was observed, suggesting that CMV infection may play an important role in CD4+ T-cell depletion in our HIV+ population.