Immunological effects of zinc deficiency in sickle cell anemia (SCA)

Zinc deficiency occurs frequently in SCA subjects. Our studies have shown that several parameters of cellular immune functions may be altered in SCA subjects and related to a deficiency of zinc. These include anergy to certain common antigens, which was reversible following zinc supplementation, decreased activity of natural killer (NK) cells, decreased production of interleukin (IL-2), decreased T4/T8 ratio and serum thymulin. Inasmuch as we have observed similar immunological changes in human volunteers (non-SCA) in whom we restricted only zinc intake and produced a mild specific deficiency of zinc, we conclude that the above changes in SCA were due to zinc deficiency. Although it is well known that susceptibility to infections is a common problem in SCA subjects, the pattern of infections related to cell mediated immune dysfunction has not been well documented. Whether or not supplementation with zinc will alter the pattern of infection and decrease morbidity in SCA on a long-term basis remains to be determined.