Survey of the use and clinical effectiveness of HPA-1a/5b-negative platelet concentrates in proven or suspected platelet alloimmunization

The optimal treatment of neonatal alloimmune thrombocytopenia (NAIT) is the transfusion of compatible donor platelets. The National Blood Service in England has established panels of 'accredited' donors negative for human platelet antigens HPA-1a and HPA-5b, the most commonly implicated alloantigens. We have retrospectively surveyed the frequency of use and clinical effectiveness of donations collected over a 13-month period from the Oxford accredited panel. Ninety-five per cent of hyperconcentrated platelets (HPCs) collected were issued, all for intrauterine transfusion to fetuses at risk of NAIT due to the presence of maternal platelet alloantibodies and previously affected siblings. Thirty-one per cent of paediatric platelet concentrates (PPCs) collected were issued, of which 57% were used for cases of suspected NAIT. Fifty-four per cent of adult therapeutic doses collected were issued; 5% of these were used in cases of suspected NAIT or proven post-transfusion purpura (PTP). Good increments were seen in most NAIT cases transfused with HPCs or PPCs, and a moderate increment in the one PTP case. We conclude that the establishment of accredited panels is justified and enables delivery of a clinically effective treatment for NAIT. Increased use and cost-effectiveness could be achieved by the delivery of an educational programme to neonatal unit clinical staff to increase the awareness and appropriate treatment of NAIT.