Values of Lymphocyte Subsets in Nepalese Healthy Adult Population

Introduction: CD4 T lymphocyte is the most commonly used cellular marker in tracking Human Immunodeficiency Virus (HIV) infection progression and monitoring effect of antiretroviral therapy (ART). Due to lack of local reference values of CD4 and other T lymphocytes in Nepal, most clinical decisions are based on the reference ranges of western countries. Methods: This study was conducted at three major hospitals/laboratory of central, eastern and western Nepal during November 2008 through July 2009. Using the predefined criteria, 602 (200, 202 and 200 from central, eastern and western regions respectively) healthy adult volunteers of age range 18-60 years were recruited with equal representation from each age group and sex. Blood specimens were screened for HIV following standard algorithm using ELISA and two rapid test kits based on different principles. Samples with discordant test-results were excluded. HIV sero-negative specimens were further analyzed for CD4, CD8, and CD4:CD8 ratio, and absolute lymphocyte count (ALC) by FACS count (Becton Dickinson, USA) and automated cell counter (BC-3000 Plus, Shenzhen Mindray Biomedical Electronics, Germany) respectively. Results: The average value (mean +/- standard deviation) of CD4, CD8, CD4/CD8 ratio and ALC of Nepalese adult population were found to be 786 +/- 248, 567 +/- 230, 1.52 +/- 0.59 and 2712 +/- 836 respectively. All four parameters but CD8 were significantly different with sex and females had relatively higher values. However, none of these parameters reported significant difference with age except the ALC. Conclusions: Nepalese healthy adult populations have significantly different T lymphocyte subsets compared to other countries. The present reference ranges of CD4 and other T lymphocytes may be used for any clinical purposes including classifying and monitoring disease status in HIV infected individuals, immune status evaluation, monitoring ART and accordingly making amendment in national HIV treatment guidelines in Nepal.