Reticulated Platelets and Platelet Reactivity in Renal Transplant Recipients Receiving Antiplatelet Therapy

Introduction. Renal transplant recipients are at increased risk of cardiovascular morbidity and mortality. We assessed platelet reactivity and reticulated platelets (RPs) in 90 recipients, 51(56.6%) of whom were not receiving acetylsalicylic acid (ASA) therapy (group A) and 39(43.3%) who were receiving ASA therapy, 100 mg (group B), and in 60 healthy controls (group C). Methods. Reticulated platelets were measured using a hematology automated analyzer (XE-2100; Sysmex Corp, Kobe, Japan) and were expressed as the percentage of RPs in the total optical platelet count (immature platelet fraction [IPF]), as the percentage of highly fluorescent RPs, and as the absolute number of RPs (IPF#). Platelet function was assessed using optical aggregometry (platelet aggregation) induced using 1 mmol/L of arachidonic acid, 2 or 10 mu mol/L of adenosine diphosphate, or 2 mu g/mL of collagen. Results. Group A demonstrated significantly higher values of RP compared with group B or group C. Group B demonstrated a substantially higher percentage of RPs compared with group C, which was significant only for the IPF parameter. Multiple regression analysis demonstrated that IPF and IPF# were significantly and positively related to collagen-induced platelet aggregation. Conclusion. We documented the presence of higher concentrations of RPs in transplant recipients compared with a control population, and a significant association between RPs and platelet function.