SERUM LEVELS OF CYTOKINES AND SOLUBLE-ANTIGENS IN POLYTRANSFUSED PATIENTS WITH BETA-THALASSEMIA MAJOR - RELATIONSHIP TO IMMUNE STATUS

Background. A series of immunological abnormalities has been described in patients with beta-thalassemia The aim of this study was to invest igate whether the measurement of serum levels of selected cytokines an d soluble molecules (deriving from cell membrane antigens) involved in the immune response could be useful for a better definition of such a lterations. Patients and Methods. Serum levels of interleukin-2 (IL-2) , IL-6, tumor necrosis factor (TNF), soluble (s) CD4, sCD8, sCD23 and sCD25 were measured using immunoenzymatic assays in 45 transfusion-dep endent patients affected by beta-thalassemia major and correlated to c onventional immunological indexes, such as peripheral lymphocyte subpo pulations and circulating immunoglobulins. Results. Patients with beta -thalassemia major showed increased TNF, sCD8, sCD23 and sCD25 and low er sCD4 values compared to normal controls. IL-2 and IL-6 were found t o be undetectable or within the normal range in all patients. Splenect omized patients presented lower levels of sCD8 and sCD23 than those ob served in unsplenectomized ones. A series of correlations involving TN F, sCD8, sCD23, sCD25, serum immunoglobulins and some lymphocyte subpo pulations was observed. In addition, serum markers of immune activatio n (TNF, sCD23, sCD25) correlated directly with the annual blood transf usion requirement. Despite this series of immunological anomalies, no patient had a history of repeated infectious episodes. Conclusions. Po lytransfused beta-thalassemic patients are characterized by a partial functional immunodeficiency determined by increased activity of CD8+ s uppressor/cytotoxic lymphocytes and possibly reduced activity of the C D4+ helper/inducer subset. B-lymphocytes also appear highly activated. The allo-antigenic stimulation of transfusions seems to play a major role in the determination of these defects; however, this functional i mmunological imbalance does not seem to have any clinical relevance.