Delayed haemolytic transfusion reactions (DHTRs) are seen more frequently in patients with sickle cell disease (SCD) than in other groups of patients, and are characterised by a positive direct antiglobulin test and the appearance of previously undetected red blood cell (RBC) alloantibodies in the patient's serum. Recently a syndrome of post-transfusion hyperhaemolysis has been described in children with SCD, characterised by destruction of both autologous and transfused RBCs with negative serological findings: continuation of RBC transfusion exacerbated haemolysis further. We describe a case of life-threatening post-transfusion hyperhaemolysis in an adult patient with SCD in whom severe anaemia necessitated further RBC transfusion, which was successfully performed in conjunction with intravenous immunoglobulin. This approach may be useful in the management of post-transfusion hyperhaemolysis in SCD as well as in the management of severe DHTRs.

Summary.We have performed a pilot study to examine the incidence of alloimmunization using pre-storage leucocytedepleted blood products (PLDP) in 16 previously transfused aplastic anaemia (AA) patients with no detectable HLA antibodies. A further eight AA patients with HLA antibodies received HLA-matched PLDP. Leucodepleted apheresed platelets were obtained using either Cobe spectra or Haemonetics system with an integral pall filter. Pall BPF4 filters were used for red cell preparation. Patients' sera were tested for HLA antibodies using lymphocytotoxicity (LCT). Patients who were HLA antibody negative by LCT at study entry were further tested with enzyme-linked immunoassay (ELISA). Out of 16 patients, two (12%) formed anti-HLA antibodies with a median follow-up of 9 months (range 1-15), but did not display platelet refractoriness to random donor platelets. Two patients were inadvertently transfused with non-leucodepleted blood products when later referred back to their local hospital. Both subsequently demonstrated HLA antibodies by LCT and became platelet refractory. These results contrast with a 50% incidence of HLA alloimmunization in a control group of AA patients transfused prior to this study with non-PLDP. HLA antibodies could no longer be detected by LCT in follow-up of three out of eight patients with HLA antibodies at study entry. Only one patient experienced non-haemolytic febrile transfusion reactions (NHFTR). We conclude that PLDP reduce the risk of alloimmunization even in previously transfused AA patients, PLDP are associated with a low incidence of NHFTR, and all new AA patients should receive PLDP from diagnosis.

Autoimmune haemolytic anaemia (AIHA) in infancy is rare. We report a case of AIHA in a male infant whose serum contained an antibody with apparent anti-Kpb specificity. Autoantibody with anti-Kpb specificity has been described in adults; to our knowledge, this is the first case of this kind described in infancy with AIHA. Clinical course and response to red cell transfusion are described.

Our results suggest that antibody responses against the C-terminal region of HIV gp120 and HLA class I may represent markers of apparent natural protection against HIV-1 infection.