RESUMO
Immunological abnormalities have been observed in many haemophiliacs receiving clotting factor concentrates. To determine whether similar changes also occur after repeated blood transfusions we estimated T cell subsets and cutaneous delayed hypersensitivity (CDH) in 50 multitransfused children with beta-thalassemia major (beta-TM). All patients were also tested for anti-HTLV-III/LAV antibodies. A diminished percentage of T lymphocytes (E-rosettes, T3+), and T4+ cells and a low T4/T8 ratio was found in patients as compared to age and sex matched controls (P less than 0.001). Negative CDH tests to specific antigens (Multi-test) were also found in a significantly larger proportion of beta-TM children (P less than 0.01). Antibodies against HTLV-III/LAV were negative in all patients. Decreased T4/T8 ratio in beta-TM children was primarily due to a reduction of T4+ cells and was inversely correlated to the patients' age, number of units of transfused blood (P less than 0.05) and especially to ferritin serum levels and annual iron balance (P less than 0.001). These findings indicate that immunological abnormalities in beta-TM patients appear to be acquired, transfusion-associated and related to iron load which depends on the appropriate chelation therapy.