CD4 and AIDS: The finding of high rates of non-AIDS-defining causes of death in our cohort of patients with profoundly low CD4+ T cell counts mirrors data from a mortality analysis of the pooled antiretroviral-receiving control arms of the ESPRIT and SILCAAT trials, where rates of AIDS- and non-AIDS deaths were similar and low CD4+ T cell counts were associated with not only all-cause mortality, but also fatal non-AIDS events [14].