DECREASED EXPRESSION OF CD73 (ECTO-5'-NUCLEOTIDASE) IN THE CD8-DEFICIENCY IN HUMAN PATIENTS( SUBSET IS ASSOCIATED WITH ZINC)

We used flow cytometry to observe the changes in T cell populations re sulting from zinc deficiency in subjects with sickle cell anemia (SCA) and in healthy human volunteers without SCA. Zinc deficiency was asso ciated with significant decreases in cellular zinc concentration, CD4/CD8+ ratio, and percentage of CD73+ cells in the CD8+ population. The decrease in the percentage of CD73+ cells in the CD8+ subset was sign ificantly correlated with lymphocyte zinc concentration and was accomp anied by essentially no change in the percentage of CD11b+ cells in th e CD8+ subset. Daily oral zinc supplementation in nine zinc-deficient human volunteers (25 mg elemental zinc) and in seven zinc-deficient SC A subjects (50 mg elemental zinc) resulted in increases in the absolut e lymphocyte count and significant increases in the CD4+/CD8+ ratio an d in the percentage of CD73+ cells in the CD8+ subset. In zinc-supplem ented subjects, the increase in the percentage of CD73+ cells was acco mpanied by a significant decrease in the percentage of CD11b + cells i n the CD8+ subset. Changes in the CD4+/CD8+ and CD73+/CD11b-cell ratio s in the CD8+ subset after treatment may provide a useful diagnostic c riterion for zinc deficiency in humans.