Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0039730 (thalassemia)
 10,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The relative proportions of T-cell (OKT3-positive, OKT4-positive and OKT8-positive) and B-cell (SIg-positive) populations in peripheral blood obtained from 29 chronically transfused patients with beta-thalassaemia major were compared with those of 17 healthy controls. Changes attributable to blood transfusion and/or splenectomy are described. The percentage of OKT8-positive (T-suppressor) cells found in the thalassaemic patients increased linearly (P less than 0.001) with the number of units transfused, irrespective of splenectomy. The percentage of OKT4-positive (T-helper) cells varied inversely with increasing transfusion in nonsplenectomized patients while in those who were splenectomized no significant correlation was apparent. Thus, in both groups of patients the T4/T8 ratio declined in a transfusion-related manner. The splenectomized patients experienced a marked and persistent lymphocytosis due to an increase in the number of both T- and B-cells. When the results were expressed as percentages, the greatest increase occurred in the number of B-cells, this increase being unrelated to the number of transfusions received. None of the serum parameters usually associated with iron overload or abnormal liver function correlated with the observed increases in T-suppressor and SIg-positive cells. These findings corroborate reports that transfusion of blood products may lead to decreased T4/T8 ratios. However, none of the patients studied manifested clinical signs of acquired immune deficiency syndrome (AIDS). Accordingly, studies which define transfusion related AIDS on the basis of analyses with monoclonal antibodies must be viewed with caution.
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PMID:Disproportionate lymphoid cell subsets in thalassaemia major: the relative contributions of transfusion and splenectomy. 387 79

Immune abnormalities have been reported in recipients of cellular and plasma blood products. To document the effect of current transfusion practices, we performed ex vivo lymphocyte immunophenotypic studies on patients with thalassaemia major who had received multiple (leucocyte-depleted) transfusions and patients with haemophilia A and B who had received heat viral-inactivated factor concentrates. Patients with thalassaemia major showed a significant lymphocytosis, with mainly B-cell changes consistent with ongoing B-cell stimulation associated with chronic exposure to red cell antigens. Reduced T-cell IL-2Ralpha expression would be consistent with inhibition by desferrioxamine chelation therapy. In contrast, patients with haemophilia showed predominantly T-cell changes. Patients with haemophilia A showed significantly elevated activated CD8+ cytotoxic T lymphocytes whereas those with haemophilia B showed an increase in CD8+CD11adim and CD4+CD45RA+ suppressor T cells. Several of the immune abnormalities found may be due to the presence of cytokines not removed by leucocyte filtration or destroyed by factor concentrate production (e.g. TGF-beta) causing a T-helper-2-like response. The extensive lymphocyte characterization in this study has not previously been performed and has enabled a closer examination of the functional lymphocyte immunophenotypes seen in patients treated according to current transfusion practices.
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PMID:Functional lymphocyte immunophenotypes observed in thalassaemia and haemophilia patients receiving current blood product preparations. 1035 53

Repeated transfusions for the treatment of thalassaemia major cause an insult to the patient's immune system and provoke post-transfusion purpura and haemolytic reactions that can be severe and life threatening. This study aims to investigate the presence of erythrocyte autoantibodies and CD59 expression on the surface of red blood cells (RBCs) in patients with beta-thalassaemia major, and any relationship to frequency of blood transfusion. The study looks at a total of 49 patients (both children and adults) with beta-thalassaemia major, divided into four groups according to the number of blood transfusions received and the presence or absence of the spleen. Glycosylated haemoglobin, Coombs' test (direct and indirect) and CD59 level on the RBC surface (by flow cytometry) are estimated in all patients studied. Glycosylated haemoglobin level was significantly lower in those who had received less than 10 units of blood (group III) than in those who had received more than 25 units of blood and had undergone splenectomy (group Ib), and was significantly lower in those who had received 10-25 units of blood (group II) than in those that comprised group Ib (F=3.598, P=0.0205). Considering CD59 expression, there was a marked difference between the groups. Expression was highest in group III and diminished progressively through groups II, Ia (polytransfused, non-splenectomised) and Ib (F=19.83, P=0.0000). No relationship was observed between CD59 expression and either blood group or gender. A significant negative correlation between CD59 expression and reticulocyte percentage (r=-0.538, P=0.000) and normoblast count (r=-0.5455, P=0.000) was found. A negative correlation between lymphocytosis and CD59 expression was also noted in groups III (r=-0.745, P=0.013), Ia (r=-0.5849, P=0.022) and Ib (r=-0.6711, P=0.009). Direct Coombs' test was positive in only one patient in group Ib, who also showed the lowest haemoglobin level. Thalassaemia patients exposed to multiple antigens through repeated blood transfusions showed lower CD59 expression than did those who had received fewer transfused units, which is a good method of detecting potential autoantibodies. Furthermore, a negative Coombs' test does not exclude autoimmunisation in such patients.
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PMID:Erythrocyte autoantibodies and expression of CD59 on the surface of red blood cells of polytransfused patients with beta-thalassaemia major. 1525 Jun 72