CD4 and AIDS: Subjects were selected from a larger cohort of 119 AIDS subjects with CD4 counts <300 cells/μl described in a previous study [12] on the basis of high plasma LPS above the median value for AIDS patients in the study cohort (>80 pg/ml) levels; LPS levels were determined in the previous study using the Diazo-coupled Limulus amebocyte lysate (LAL) assay.