Proteomic study of apheresis platelets made HLA class I deficient for transfusion of refractory patients.

Purpose: Refractoriness can occur after repeated platelet (PLT) transfusions because of alloimmunization to HLA class I antigens on transfused PLTs and generation of anti-HLA antibodies that bind to the foreign PLTs and initiate their destruction. Such refractoriness can be overcome by provision of HLA-matched PLTs from HLA typed donors. However, since the procedure is both expensive and time-consuming, an alternative approach is to deplete PLTs of HLA class I molecules by a brief treatment with citric acid, on ice. This is shown to be feasible without damaging PLT function. We used label free quantitative mass spectrometry (MS)-based proteomics to investigate the effect of acid treatment on apheresis PLTs for combatting immunologic PLT refractoriness.

Experimental Design: Proteomic analyses are undertaken using PLTs from seven apheresis concentrates, which were split in two with or without acid treatment.

Results: In total 1717 proteins in apheresis PLTs were quantified using proteomics. Data are available via ProteomeXchange with identifier PXD027893 . Of these, the amount of 80 proteins changed significantly after acid treatment, but overall there were not any major differences in proteomes between samples with and without acid treatment.

Conclusions And Clinical Relevance: In general, the changes of PLT proteins after treatment with citric acid were quite small and functionally safe. Hence, this result taken together with our previously published data indicates that acid treated PLTs can be used for treatment of patients with PLT refractoriness and opens up for a clinical trial.