Normal values of CD4 and CD8 lymphocyte subsets in healthy indian adults and the effects of sex, age, ethnicity, and smoking

BACKGROUND: Information on lymphocyte populations (T, B, and natural killer cells) and subpopulations (CD4 and CD8) in India is generally lacking. Measurement of T-cell subsets is important in India for evaluating disease stage and progression in individuals with the human immunodeficiency virus (HIV). Hence, this study was conducted to provide normal ranges of absolute and percentage values of CD4 and CD8 T-lymphocyte subsets and the ratio of CD4 to CD8 in normal Indian adults. METHODS: Flow cytometric analysis (EPICS-XL) was used to determine the range of T-lymphocyte subpopulations in normal Indian blood donors at Command Hospital and the Armed Forces Medical College, Pune, India. The reference population consisted of 94 healthy HIV-seronegative blood donors. T-lymphocyte subsets were analyzed with two-color immunophenotyping of peripheral blood lymphocytes with the use of a lysed whole-blood technique and enumerated. RESULTS: For normal values of various blood components, we found mean values of 2114 cells/microl for total lymphocytes, 865 cells/microl (40.2%) for CD4(+) lymphocytes, 552 cells/microl (31.3%) for CD8(+) lymphocytes, and 1.7 for the CD4:CD8 ratio. The 95% confidence intervals for the same parameters were 1115-4009 cells/microl, 430-1740 cells/microl (30.75-49.60%), 218-1396 cells/microl (20.06-42.52%), and 0.39-3.02 respectively. Females had significantly higher CD4 counts (P < 0.05), percentage of CD4 lymphocytes (P < 0.01), and CD4:CD8 ratio (P < 0.01). Males had a significantly higher percentage of CD8 lymphocytes (P < 0.01). They also had higher CD8 counts that did not reach significance. Age, ethnicity (Dravidian versus Aryan), smoking, alcohol consumption, and the interval between drawing the blood sample and its analysis were factors that did not produce statistically significant differences in the T-cell subsets studied. CONCLUSIONS: When compared with other published series, the CD4 and CD8 values in healthy Indians were no different from those reported in the West. These observations have important clinical implications for the use of T-lymphocyte subset measurements in India, especially in the management of HIV infection. The normal ranges established by this study can be used as a reference for decisions made in clinical practice.