Cross-sectional analysis of CSF neopterin in HIV disease in the context of other CSF and blood measurements. Included are 53 HIV-seronegative volunteers; untreated HIV positive neurologically asymptomatic (NA) subjects; 53 with CD4+ counts <50 cells/μL (mean age 38.9); 69 subjects with 50-199 cells/μL (mean age 38.6); 69 with counts 200-349 cells/μL (mean age 38.8); and 108 with CD4+ counts >350 cells/μL. Untreated patients with ADC were divided into 30 with Stage 1, and 53 with Stage 2-4. Treated subjects included 150 with plasma HIV RNA suppressed below 50 copies/mL (treatment successes) and 83 with >50 copies/mL (treatment failures) after >6 months of treatment. The OI group included 73 patients with CNS opportunistic diseases (see text). The boxes show the 25-50th quartile with median bar and mean +, while the whiskers show the 10-90th quartile. A. CSF neopterin. Overall ANOVA P < 0.0001, Dunn's post hoc comparisons showed that HIV- group differed from all HIV+ groups (P < 0.001 except Sucesses P < 0.5); ADC 2-4 differed from all NAs (P < 0.01- 0.001) but not from ADC 1 group; the ADC 1 group differed from the NA CD4 >350 (P < 0.05) and 200 - 349 (P < 0.001) but not from other NA groups. The treated successes differed both from all the untreated HIV-infected groups (P < 0.001) and the HIV negatives (P < 0.05), while the treated failures also differed from the untreated HIV-infected (P < 0.05- 0.001), except those with CD4 >350, and from the HIV- (P < 0.001). The OI group differed from the NAs with CD4>200 and treated groups but not from those with lower counts or from ADC groups. B. Plasma neopterin. Statistical analysis was similar to CSF except that ADC 2-4 differed only from the two higher CD4 NAs (P < 0.01- 0.001) and the ADC 1 only from the CD4 >350, and the treatment successes did not differ from the HIV seronegatives while the failures did (P < 0.001). C. CSF HIV RNA. D. Plasma HIV RNA. E CSF WBC counts. F. Blood CD4+ T cell counts. Abbreviations: HIV-, HIV seronegative control group; NA, neurologically asymptomatic; ADC, AIDS dementia complex; Rx Success, treated with plasma suppression to <50 copies HIV RNA per mL; Rx Failure, treated with continued plasma viremia with ≥ 50 copies HIV RNA per mL.