ABSTRACT
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 CDS [all T cells], CD4 [T helper/inducer cells], CDS [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 CDS 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