Platelet transfusion alters CD40L blood level and release capacity in patients suffering from thrombocytopenia

BACKGROUND: Platelet (PLT)‐derived cytokines, such as soluble CD40 ligand (sCD40L), play an important role in the development of adverse transfusion reactions associated with the administration of PLT products. In this study, we determined sCD40L concentration and release capacity in patients with thrombocytopenia before and after receiving a PLT transfusion. STUDY DESIGN AND METHODS: The study included 12 patients suffering from chemotherapy‐induced thrombocytopenia. sCD40L levels and release capacity were measured in plasma samples of the patients before and after PLT administration as well as in the respective plateletpheresis concentrates by enzyme‐linked immunosorbent assay. Sixteen healthy blood donors served as a control group. RESULTS: In PLT concentrates, elevated sCD40L levels (2567 ± 134 pg/mL) were observed in comparison to plasma sCD40L levels in controls (238.4 ± 35.3 pg/mL). sCD40L plasma concentration of patients with thrombocytopenia was significantly reduced (86.3 ± 16.7 pg/mL) before transfusion and increased to nearly normal levels (204.4 ± 24.8 pg/mL) after PLT administration. In parallel, the sCD40L release capacity per PLT showed no significant difference between controls and patients with thrombocytopenia before transfusion (33.3 ± 2.6 and 29.3 ± 4.6 ag/PLT, respectively) but was significantly reduced after PLT transfusion (22.4 ± 2.7 compared to 29.3 ± 4.6 ag/PLT). CONCLUSIONS: In patients with thrombocytopenia, sCD40L levels were clearly influenced by PLT transfusions: PLT administration led to a normalization of sCD40L plasma concentration. Nevertheless, adverse transfusion reactions did not occur in these patients. The sCD40L release capacity was enhanced by PLT administration dependent on the increase in the amount of PLT count.