Alloimmunization in Chinese with warm autoimmune haemolytic anaemia - incidence and characteristics.

We perform a retrospective study to determine the incidence and characteristics of alloimmunization in Chinese patients with warm autoimmune haemolytic anaemia. Among 67 patients studied, clinically significant alloantibodies were found in only eight patients, giving a rate of alloimmunization of 11.3%. The latter contrasts with the much higher rate reported in the Western population. This probably reflects the genetic homogeneity in Chinese with respect to the red cell phenotype. The alloimmunization rate, however, is still significant and therefore comprehensive pretransfusion testing is required for Chinese patients with warm autoantibodies so as to safeguard patient's safety.