ABSTRACT
Beta-thalassemia major is one of the major health problems in our country. Many studies have confirmed the fact that, these patients have an increased susceptibility to bacterial infections. In this study, we have assessed the humoral immune system in 68 thalassemic patients by measuring their serum concentration of Immunoglobulin G [IgG], IgM, IgA, C3 and C4 in order to find out a responsible immune defect. Sixty eight beta-thalassemia major patients were enrolled randomly from referrals to Dastgheib clinic of thalassemia. The same number of case controls with matched age and sex were selected from healthy people without any history of recent or recurrent infections. Serum IgG, IgM, IgA, C3 and C4 levels were assessed using Single Radial Immunodiffusion [SRID]. Serum levels of IgG, IgM and IgA were significantly higher [P<0.01] and those of C3 and C4 were significantly lower [P<0.01] in thalassemic patients than the controls. Considering the result of analytic tests, it was revealed that, thalassemia patients show much more increase in serum immunoglobulin levels as they get older. Splenectomized patients had higher serum IgG and IgA levels than non-splenectomized patients but had no difference in serum IgM, C3 and C4. Serum ferritin level had no correlation with the changes of humoral immunity; however, patients with serum ferritin level >2500ng/ml had higher serum IgM level. These results can be due to continuous exposure to antigens, repeated infections, chronic liver disease and splenectomy but not iron overload. The only probable cause of humoral immune deficiency found in these patients is a defect in serum complement levels