Reference ranges for lymphocyte subsets in adults from western India: Influence of sex, age and method of enumeration

Background: The enumeration of absolute CD4 counts is of primary importance, since therapeutic protocols for HIV1 patients are based on these.
Aims: To establish reference ranges for the CD4 and CD8 T-lymphocytes in the Indian population.
Settings and Design: Enumeration of absolute numbers and percentages of lymphocyte subsets was performed in 252 healthy adult Indians.
Methods and Materials: The assays for SPT were carried out using the Beckman EPICS XL-MCL flow cytometer and the cytostat tetraCHROME reagent containing CD45/CD8/CD4/CD3 monoclonal antibodies. For comparison with DPT the absolute lymphocyte count was obtained using the Coulter STK-S fully automated hematology analyzer.
Statistical Analysis: Regression analysis and Students t test were used for data analysis.
Results: Median values were as follows; absolute CD3 counts 1446 cells/mm³ (total), 1361 cells/mm³ (males) and 1511 cells/mm³ (females); absolute CD4 counts are 771 cells/mm³ (total), 705 cells/mm³ (males) and 839 cells/mm³ (females); absolute CD8 counts are 555 cells/mm³ (total), 552 cells/mm³ (males) and 561 cells/mm³ (females). The median CD4/CD8 ratio for the total samples was 1.34, for males 1.22 and for females 1.49.
Conclusions: In this study we have established reference ranges for normal Indian adults using the fully automated Single Platform Technology. The lymphocyte subsets values of our population are closer to those of the population from Botswana and China rather than the Western population. The absolute CD3 and CD4 counts and the CD4:CD8 ratio are higher in females than in males. Consistently higher values are obtained by the DPT as compared to the SPT.

Keywords
CD4 T lymphocytes, CD-8 T-lymphocytes, reference range, single platform flow cytometry.