Lymphocytes in beta-thalassemia/HbE: subpopulations and mitogen responses

Lymphocyte subpopulations and proliferative responses to mitogens of 24 beta-thalassemia/HbE patients were studied and compared with those of 23 healthy controls. Results of the study were analyzed in correlation with clinical aspects i.e. severity of disease (anemia), frequency of infections and iron status. T(CD3+) lymphocytes were found to increase in thalassemic patients compared to normal controls. The CD4+ or CD8-positive lymphocytes and CD4/CD8 ratio were not statistically different from normals. Without mitogen, lymphocytes from thalassemic patients incorporated more [3H]Tdr than those from normal controls. Stimulation index (SI) of these cells after various mitogens were lower than in normal subjects. The observations were more obvious in patients with severe disease (severe anemia) and those who had frequent infections. These findings suggest that lymphocytes from thalassemic patients are activated in vivo. Whether these cells are less efficient in response to new or previously unexposed antigens remains to be proven.