Lymphocyte subsets and specific T-cell immune response in thalassemia

Infection is very common in thalassemia and is one of the-major causes of d eath. To date, it is not quite clear why these patients are susceptible to infection. In this study, lymphocyte immunophenotyping for CD3(+) (T-cells) , CD3(+)CD4(+) (T-helper/inducer cells), CD3(+)CD8(+) (T-suppressor/cytotox ic cells), CD3(-)CD19(+) (B-cells), and CD3(-)CD16/56(+) (natural killer ce lls) subsets and expression of the activation antigen CD69 on CD3(+)CD4(+) and CD3(+)CD8(+) T-cells were determined in the:whole blood of thalassemia patients, using a three-color flow cytometric technique. Results showed tha t only splenectomized beta-thalassemia/hemoglobin (Hh) E patients displayed a marked increase in absolute number of all lymphocytes, In addition, sple nectomized beta-thalassemia/Hb E showed a significantly lower percentage of CD3(+) cells, with a corresponding increase in CD19(+) cells. These differ ences, when compared with normal subjects and other thalassemia patients, m ay he attributed to splenectomy, alpha-thalassemia patients, on the other h and, showed no significant difference from the normal group. While lymphocy te subsets in splenectomized beta-thalassemia/Hb E patients showed an abnor mal distribution, T-cell activation in these patients was not different fro m the activation seen in normal subjects. This implies that thalassemia pat ients, during the steady state of disease, appear to have normal T-lymphocy te function with only moderate abnormalities of T- and B-lymphocyte subsets . (C) 2000 Wiley-Liss, Inc.