CD4 counts of normal and HIV-infected south Indian adults: do we need a new staging system?

BACKGROUND The normal range of CD4 lymphocyte count varies among different ethnic groups. In populations with CD4 counts inherently lower than in the West, the Centers for Disease Control and Prevention (CDC) classification system of HIV-infected individuals may not be appropriate. No such criterion is currently available for ethnic south Indian HIV-infected individuals. We undertook this study to assess the applicability of the western case definition to south Indian HIV patients. METHODS The CD4 counts of 104 normal and 79 HIV-infected south Indian adults were estimated by flowcytometry. The mean CD4 counts were estimated and compared between CDC groups A, B and C and controls. Receiver operator characteristics curves were generated to determine the cut-off that correlated best with clinical staging for this population. RESULTS The mean CD4 and CD8 cell counts/microl and the CD4/CD8 ratio of the control group were 799.0, 919.6 and 0.94, respectively. For CDC groups A, B and C, the mean CD4 counts/microl were 454.4, 254.4 and 168; mean CD8 counts/microl were 1156, 1070.9 and 1191.3; and mean CD4/CD8 ratios were 0.44, 0.25 and 0.15, respectively. CONCLUSION The mean CD4 count among normal south Indians is significantly lower than that in the western population and parallels that of the Chinese. When categorized based on the CDC classification system, the mean CD4 count of HIV-infected individuals was lower. Categories of CD4 counts > 300, 81-300 and < or =80 cells/microl and CD4% > 14, 7-14 and < or = 6 correlate better with disease progression among HIV-infected individuals. A longitudinal study is required before guidelines for the Indian population can be devised.