Platelet transfusion refractoriness responding preferentially to single donor aphaeresis platelets compatible for both ABO and HLA.

Platelet transfusion refractoriness is challenging to manage. When human leucocyte antigens (HLA)-sensitized patients fail to respond to HLA-matched (HLA-m) platelets, non-immune destruction may be assumed, and collections of HLA-m platelets abandoned. We report cases of highly HLA-sensitized patients whose only satisfactory platelet transfusion responses were consistently associated with products compatible for both HLA- and ABO-matched (HLA-m/ABO-m) platelets, and in whom unsatisfactory increments occurred if either form of major incompatibility was permitted (HLA-u or ABO-u). Absolute platelet increments (APIs) were measured and classified as satisfactory if ≥10 and unsatisfactory if <10. Patient 1, age 59 years, group O, with myelodysplastic syndrome/acute myelogenous leukemia (MDS/AML), was unresponsive to either fresh ABO-m or HLA-m platelets. Of 17 HLA-m platelets, satisfactory responses occurred for 75% of HLA-m/ABO-m units, and failures for 100% of HLA-m/ABO-u, with mean API differing significantly (14·1 vs 1·1, P = 0·0059). Of 36 HLA-m platelets given to patient 2, age 49 years, group O, Gravida 2 Para 2, with severe aplastic anaemia, a satisfactory response occurred with 75% of HLA-m/ABO-m units, and failures for 63% of the HLA-m/ABO-u (mean API 26·7 vs 7·6, P = 0·008). Increment failures from HLA-m platelets need not imply intractable refractoriness. If resources permit, selection of HLA-m/ABO-m platelets may optimise the incremental response.