ANALYSIS OF PERIPHERAL-BLOOD LYMPHOCYTE SUBSETS IN NORMAL SAUDI MALES BY FLOW-CYTOMETRY

Lymphocyte immunophenotyping using flow cytometer has become an important tool for clinical patient management as well as for research and epidemiological studies. We examined the distribution of CD3 (all T cells), CD4 (T helper/inducer cells), CD8 (T suppressor/cytotoxic cells), CD16 (natural killer cells) and CD19 (B cells) in 150 healthy Saudi male blood donors using flow cytometry. The two-color labeled cells were analyzed by using the flow cytometer (FACScan, Becton-Dickinson, San Jose, California, USA) and the dual fluorescent subsets were discriminated by Simultest software. The distribution of T lymphocytes, B lymphocytes, and natural killer (NK) cells were similar to those reported in other populations as well as in normal Caucasian expatriate donors (all males) (n = 40) who were included in this study as controls. However, a significantly decreased CD4/CD8 ratio was observed in most Saudi blood donors. These lower ratios were due to decreased CD4 together with an increase in CD8 cells. Significant (P < 0.0001) difference in CD4/CD8 ratio in our study may be due to environmental factors such as ultraviolet radiation and stress (heat) as well as some genetic factors.