Two patients had platelet transfusion refractoriness accompanied with non-hemolytic-, and non-febrile-hypersensetivity reactions nevertheless HLA-, and HPA-matched platelets were used. Whether the development of hypersensitivity reactions and refractoriness were associated with HLA or ABO match grade between patient and donor, we estimated corrected count increment at 1-hour posttransfusion (CCI-1hr) after HLA-, and HPA-matched platelet transfusion. The CCI-1hr more than 0.75×104/μl was used to determine adequate transfusion response.
Regardless of HLA or ABO match grade, hypersensitivity reactions following HLA-, and HPA-matched platelet transfusion were observed in 14 of 23 transfusions in case 1, and in 6 of 15 transfusions in case 2. When there were any hypersensitivity reactions, adequate transfusion responses were obtained in 4 (29%) of 14 transfusions in case 1, and in 2 (33%) of 6 transfusions in case 2. However, effective increments were observed in most of transfusions (78%, 89%, respectively) when hypersensetivity reactions were not found.
Heal et al. hypothesized that antibodies to polymorphic plasma proteins could be involved in platelet transfusion refractoriness by an “innocent bystander” or “immune complex” mechanism, our findings were strongly suggestive of their possibility.
