Provision of human leukocyte antigen (HLA) selected platelets: 10-year experience of a regional blood centre

Background: Human leukocyte antigen (HLA) selected platelets are frequently requested in patients with platelet transfusion refractoriness (PTR) due to HLA alloimmunization. A retrospective study was conducted to evaluate the provision of HLA-selected platelets by a regional blood centre from May 2010 to April 2020. Methods: In the study period, 1,080 units of HLA-selected platelets were collected from 393 donors recruited from the unrelated bone marrow donor registry. They were transfused to 147 patients (male 54%, mean age 48 +/- 21 years). Analysis was performed in each donor-recipient pair to identify the predictors of haematological response. Results: HLA-A and -B antigens in all except one donor-recipient pairs were 4 out of 4 matched. In 84% of instances, mean 1-hour corrected platelet count increment (CCI) were greater than 7,500 m(2)/mu L, the threshold of satisfactory increment. Improvement in 1-hour CCI (CCI (HLA selected platelets) - CCI (random donor platelets)) of patients who were not refractory to random donor platelet transfusions was 11,134 m(2)/mu L (95% CI: 6,122-16,135 m(2)/mu L) less than those who had PTR. Following HLA-selected platelet transfusions, male patients' mean 1-hour CCI was 3,592 m(2)/mu L (95% CI: 1,270-7,145 m(2)/mu L) less than that of female patients. Mean 1-hour CCI was 8,727 m(2)/mu L (95% CI: 595-12,970 m(2)/mu L) higher in patients who demonstrated anti-HLA antibodies. ABO compatibility did not significantly influence 1-hour CCI. Conclusions: HLA-selected platelets provided locally were almost exclusively 4 out of 4 matched and resulted in satisfactory 1-hour CCIs. In addition to expanding the donor pool, advocating judicious request for the product and thorough investigations of PTR could enhance service provision.