Lymphocyte subsets and specific T-cell immune response in thalassemia

Abstract

Infection is very common in thalassemia and is one of the major causes of death. 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/cytotoxic cells), CD3 CD19 (B-cells), and CD3 CD16/56 (natural killer cells) 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 that only splenectomized-thalassemia/hemoglobin (Hb) E patients displayed a marked increase in absolute number of all lymphocytes. In addition, splenec-tomized-thalassemia/Hb E showed a significantly lower percentage of CD3 cells, with a corresponding increase in CD19 cells. These differences, when compared with normal subjects and other thalassemia patients, may be attributed to splenectomy.-thalassemia patients, on the other hand, showed no significant difference from the normal group. While lymphocyte subsets in splenectomized-thalassemia/Hb E patients showed an abnormal distribution, T-cell activation in these patients was not different from the activation seen in normal subjects. This implies that thalassemia patients, during the steady state of disease, appear to have normal T-lymphocyte function with only moderate abnormalities of T-and B-lymphocyte subsets.

THE ROLE OF Treg CELLS AND FoxP3 EXPRESSION IN IMMUNITY OF β-THALASSEMIA MAJOR AND β-THALASSEMIA TRAIT PATIENTS

“…Difference in splenectomized patients percentages in these studies compared to the current study might be an explanation of the differences in B-lymphocyte results. Nevertheless, immunoglobulin results were consistent with the previous studies [5,[22][23][24].…”

“…Contradictory results were reported in the literature for B cells in thalassemic patients. Our findings of normal B lymphocytes were in agreement with the study reported by Musumeci et al [22], but not consistent with the findings reported by Dwyer et al [5] and Pattanapanyasat et al [23]. A significant increase in CD19 + B cells was shown, particularly in splenectomized ones, and the mechanism suggested for increased CD19 + B cells in these studies was redistribution of B lymphocytes from the spleen to the circulating pool.…”

“…A significant increase in CD19 + B cells was shown, particularly in splenectomized ones, and the mechanism suggested for increased CD19 + B cells in these studies was redistribution of B lymphocytes from the spleen to the circulating pool. In the above-mentioned two studies, percentages of splenectomized thalassemia major patients were 50%, compared to 27% in our study [5,23]. Difference in splenectomized patients percentages in these studies compared to the current study might be an explanation of the differences in B-lymphocyte results.…”

“…These technological differences might be an explanation for discrepancies between these 2 studies. Another study by Pattapanyasat et al showed no significant differences in any of the T-lymphocyte subsets except in splenectomized β-thalassemia patients in whom a significant decrease were seen in the percentage of CD3 + CD8 + T cells [23]. Most of the splenectomized patients rarely had transfusions less than 1-2 units/year or never received transfusion.…”

The Role of Immune System in Thalassemia Major: A Narrative Review

“…Different subsets of lymphocytes, including helper T cells, suppressor T cells, NKCs, and B cells (distinguished by respective phenotypic signatures of CD3+/CD4+, CD3+/CD8+, CD3-/CD16/56+, and CD3-/CD19+) have been reported with increased number in TM patients (21,22). Excess iron may exert executive effects on the ratio of T cell subsets, which may be reflected by increased number of CD8+ lymphocyte while decreased CD4+ subset (23).…”