Transfusion-induced platelet antibodies and regulatory T cells in multiply transfused patients

Platelet transfusion refractoriness (PTR) remains a difficult problem in patients requiring long-term platelet supportive care. However, there are little data on the frequency of platelet antibodies in multiply transfused Chinese patients. Moreover, the relationship between peripheral regulatory T cells (Tregs) and PTR remains unclear.

We retrospectively studied the frequency of alloimmunization against platelet antigens in patients receiving multiple transfusions between 2013 and 2017. Monoclonal antibody solid-phase platelet antibody test (MASPAT) kits were used to screen for platelet antibodies before each platelet transfusion. Peripheral Tregs and CD4⁺ CD25⁺ CD127^- T cells were detected by flow cytometry, while transforming growth factor-beta (TGF-β) and interleukin (IL)-17 cytokines were detected by enzyme-linked immunosorbent assay.

A total of 399 patients who met the inclusion criteria were enrolled for the analysis of platelet antibodies and refractoriness. Among these patients, 10 (2.5%) were positive for platelet antibodies before transfusion and 47 (11.8%) became antibody-positive during the study period. The number of alloimmunized patients was significantly higher in patients with hematological disease as compared with other disease groups (p < 0.05). Refractoriness and alloimmunization occurred in 77 (19.3%) and 22 (28.6%) patients, respectively. There were no significant differences in CD4⁺ , CD8⁺ , and CD4⁺ CD25⁺ CD127^- T cell numbers and plasma levels of TGF-β1 and IL-17 between patients with PTR and the control group.

Refractoriness was common in patients undergoing multiple platelet transfusions (19.3%), with alloimmunization observed in 28.6% of patients. However, Tregs in peripheral blood may not play a key role in PTR.