Suppression of irreversibly sickled erythrocytes by zinc therapy in sickle cell anemia.

Zinc administered orally to 12 patients with SCA decreased the mean number of circulating ISC's from 28.0% before treatment to 18.6% during treatment. Seven of the 12 patients had statistically significant individual decreases in ISC counts, and two others had moderate reduction in ISC's of borderline significance. Patients who did not have a significant decrease in ISC count while on zinc therapy had low counts initially. The decrease in ISC's may mean improved oxygenation. The decrease in ISC's provides objective evidence of an in vivo effect of oral zinc treatment in SCA. The role of ISC's in the pathology and symptomatology of SCA is unknown, but some evidence suggests that ISC's may be related to vascular and organ damage. If so, therapies which decrease ISC counts, such as zinc, have the potential of reducing organ damage.