As a group, the CSF neopterin in the OIs differed from: the HIV negatives (P < 0.001); both treatment groups (P < 0.001); NAs with blood CD4 counts >350 cells/μl (P < 0.001); and NAs with CD4 200-349 (P < 0.05); But they did not differ from the NAs with CD4 50-199 or <50 or from either ADC group. This evidence concerns the gene CD4 and AIDS dementia complex.