The impact of neocyte transfusion in the management of thalassaemia.

Transfusional iron overload leading to cardiopathy and other severe complications continues to be a major problem in chronically transfused homozygous beta-thalassaemia patients. It is well known that young red cells (neocytes) survive longer after transfusion and therefore may contribute to the extension of the intervals between transfusions. We evaluated the impact of neocytes in the total annual blood requirements and consequently the transfusional iron load in 18 thalassaemia patients. A two-period study comparing transfusions of standard red cells versus neocytes in the same group of patients was performed. Neocytes were harvested by density separation using the Neocel System. The method of preparation was simple with relatively low costs and required no special equipment. There was a significant difference (p < 0.005) in PK and MCV values of the neocyte and older red cell (gerocyte) fractions indicating that a good separation of the two populations was achieved. All patients had a reduction in blood requirements during the neocyte period. The total annually transfused red blood cells and concomitant iron blood load were significantly reduced (p < 0.001) by 20.2 +/- 9.1%. However, the response was variable. Seven of the 18 patients had a large reduction in blood consumption (24.8-34.8%), 9 others ranged between 10.7 and 21.6%, and in 2 the reduction was less than 10%. This reduction in blood requirements and in the transfused iron may change the chelation index resulting in more efficient iron chelation therapy and perhaps reduce the cost of the haemochromatosis therapy on a long-term basis. We conclude that the use of neocyte therapy using this system can benefit the majority of chronically transfused patients by reducing transfusional iron overload and related complications and may lead to a much better quality of life.

[Clinical evaluation of various preventive methods for non-hemolytic transfusion reactions]. / Evaluation clinique de différentes méthodes préventives des réactions transfusionnelles non hémolytiques.

A study has been carried out on the incidence of non-hemolytic transfusion reaction on a group of patients suffering from thalassemia. Of this group, the rate of reactions per patient, based on the relationship between the number of patients with non-hemolytic transfusion reactions and the total number had risen to 31.8%. 83.7% of the patients with non-hemolytic transfusion reactions did not give a positive reaction to lymphocytotoxicity. 654 patients having, or not having shown a non-hemolytic transfusion reaction received washed red cell concentrates prepared extemporaneously. This process allowed the rate of reaction per patient to drop to 3.9%. The transfusion of deleucocytated red cell concentrates by filtration, carried out on a group of 188 patients, made the rate of reaction per patient drop to 2.8%. As regards to rate reaction per patient, there is no significant difference statistically between these two groups, however, it must be pointed out that the administration of filtered red cell concentrates, by deleucocytation, notably improves the incidence of a feverish reaction, while the administration of washed red cell concentrates has an important impact on allergic reactions. Interestingly, in solution, the washed red cell concentrates have the added advantage of having only very small quantities of free iron or vasoactive proteic derivatives. The new four bag system, now allows us to collect, separate and wash in a closed circuit. Compared to the traditional method this system has the advantage of assuring greater efficiency and security. In conclusion, for the first time, the administration of washed red cell concentrates on patients who receive regular transfusions, may represent a good procedure, combined or not with deleucocytation by filtration, as to prevent the occurrence of non-hemolytic reactions.

Sister-chromatid exchange in highly purified human CD4+ and CD8+ lymphocytes.

Sister-chromatid exchange (SCE) frequencies were determined in human peripheral blood CD4+ and CD8+ T lymphocyte subpopulations which were rapidly and highly purified from pooled T lymphocytes by immunological methods. The purified lymphocytes were stimulated with phytohemagglutinin (PHA) for 4 days. CD4+ lymphocytes showed significantly higher SCE frequencies than autologous CD8+ lymphocytes when measured simultaneously after identical bromodeoxyuridine (BrdU) incubation times. Differences in SCE frequencies between CD4+ and CD8+ lymphocytes were also detected when mitomycin C (MMC) was added to the cultures. Higher SCE frequencies in CD4+ lymphocytes were associated with lower proliferating rate indices (PRI) as compared to autologous CD8+ lymphocytes. Abnormalities in CD4+ T lymphocyte function and number in peripheral blood have been observed in several diseases characterized by immunological disorders. Thus, our data may suggest a link between some immunological disturbances and abnormal SCE frequencies in T lymphocyte subsets.

Red cell alloantibodies in patients with thalassemia.

We present the results of tests carried out to detect alloimmunization against red cells in 1,200 patients (607 males and 593 females), transfused and followed up during the period 1981-1987 in our hospital. Of these patients, 1,135 were thalassemic and 65 had sickle cell/beta-thalassemia. In 162 patients who received blood matched for the AB0, rhesus and Kell systems from their first transfusion, the immunization rate was very low (3.7%). In a pilot group consisting of 83 patients with the same clinical characteristics, who received blood matched only for the AB0 and Rh-D antigens, there was a significant difference in the frequency of alloantibodies (15.7%, p less than 0.001). Of 1,038 patients who received blood only matched for AB0 and Rh-D 244 (23.5%) with one or more red cell alloantibodies were identified. Of these 1,038 patients, 973 were exclusively thalassemic. In 220 (22.6%) of them, alloantibodies were found. The sickle cell beta-thalassemia patients presented alloantibodies with a higher frequency (36.9%, 24/65). Only one antibody was found in 114 patients (51.8%) and two or more in 106 patients (48.2%). The alloimmunization significantly concerned the rhesus (34.0%) and Kell (29.8%) systems. Anti-Kell was most often identified (28.5%). Alloimmunization appears considerably lower in patients in whom blood transfusion is started before the age of 3 than in those in whom it is started after that age (20.9 vs. 47.5%, p less than 0.0001).