Impairment of natural killer (NK) function in carriers and patients with thalassemia major

To evaluate natural killer cytotoxicity (NKC) and its regulation by interferon (IFN) in thalassemia major (TM), we studied 19 patients, 10 carriers (parents of 10 different patients) and 35 normal subjects (children and adults) as controls. We have found a diminished NKC, as well as a decrease in the percentages of cells bearing IgGFc receptors in TM patients, whereas they were normal in TM carriers. Although alpha-IFN enhanced NKC in TM patients and carriers, Con A (an IFN inducer) had no enhancing effect on NKC from either patients or carriers. These agents did not modify the expression of IgGFc receptors in cells from TM patients, carriers or normal controls. Our results indicate that TM patients have a defect in NK cell maturation or activation, which is reversed by alpha-IFN. The failure of TM patients and carriers to respond to Con A suggests a defect in NKC regulation which might be related to a genetic origin.