Alloimmunization to red cell antigens in thalassemia: comparative study of usual versus better-match transfusion programmes.

Transfusion records and serological data concerning 120 regularly transfused thalassemic children were followed up, beginning with their first transfusion, for a 5-year period. All patients had been phenotyped for 18 red cell antigens before their first transfusion. The usual-match (UM) group consisted of 64 children who received blood compatible with their ABO and Rho (D) antigens. The better-match (BM) group comprised 56 children who received blood compatible with ABO, CcDEe and K antigens. It was found that a statistically significant difference does not exist in the overall frequency of alloimmunization between the UM (23.43%) and BM group (14.28%) and also between the children that started transfusion therapy before they were 12 months old regarding UM (9%) and BM policies (5.2%). However, a large numerical difference, which might become statistically significant with a larger number of patients was observed in the group of children who were started on transfusions after they were 12 months old, between the UM (38.7%) and BM (18.9%) policy. Finally, a statistically significant difference (less than 0.005) was found only between the children that started transfusions early (7.69%) and those that started them later in life (27.9%), irrespective of the transfusion policy observed. We report, in this study, the mean transfusion numbers of immunized and nonimmunized patients and the frequency, specificity and clinical significance of the identified antibodies are analyzed. Our conclusion is that a BM policy in transfusion programmes, including at least the Rhesus and Kell antigens, is recommended for all thalassemic children that start transfusion therapy after they are 12 months of age; if they start earlier, observation of the BM policy is not necessary.