Immunophenotyping of peripheral blood lymphocytes in Saudi men.

Flow cytometry is an important tool for the diagnosis and follow-up of immunodeficiency patients, as well as for patients with leukemia and lymphoma. Lymphocytes and their subsets show variations with race. The aim of this study was to establish reference ranges for lymphocytes and their subsets in an Saudi adult population by using flow cytometry. Blood samples obtained from 209 healthy Saudi men were used for this study. All blood donors were between 18 and 44 years old. Lymphocytes and their subsets were analyzed by flow cytometry, and the absolute and percentage values were calculated. We investigated the expression of T-cell markers (CD3, CD4, and CD8), B cells (CD19), and natural killer cells (CD16 and CD56). The absolute and percent values of each cell subset were compared with published data from different populations by using the Student t test. Reference ranges, each expressed as the mean +/- the standard deviation, were as follows: leukocytes (6,335 +/- 1759), total lymphocytes (2,224 +/- 717), CD3 cells (1,618 +/- 547), CD4 cells (869 +/- 310), CD8 cells (615 +/- 278), CD19 cells (230 +/- 130), and CD3-CD16(+)/CD56+ cells (262 +/- 178). The CD4/CD8 ratio was 1.6 +/- 0.7. Our results for B cells, CD4 cells, and CD8 cells and for the CD4/CD8 ratio fell in between the reported results for Ethiopian and Dutch subjects. Our results were also different from previously reported findings in an Saudi adult population that showed no increase in CD8 T cells. We thus establish here the reference ranges for lymphocytes and their subsets in a large cohort of Saudi men. The CD8 cell count was not abnormally high, as previously reported, and fell in between previous results obtained for African and European populations.