The influence of acute moderate-to-high intensity aerobic exercise on markers of immune function and microparticles in renal transplant recipients.

Renal transplant recipients (RTRs) and non-dialysis chronic kidney disease (ND-CKD) patients display elevated circulating microparticle (MP) counts, whilst RTRs display immunosuppression-induced infection susceptibility. The impact of aerobic exercise on circulating immune cells and microparticles is unknown in RTRs. Fifteen RTRs (age 52.8±14.5 years, estimated glomerular filtration rate [eGFR] 51.7±19.8 ml/min/1.73m2 [mean ± SD]), 16 ND-CKD patients (54. ± 6.3 years, eGFR 61.9±21.0 ml/min/1.73m2, acting as a uremic control group), and 16 HCs (52.2±16.2 years, eGFR 85.6±6.1 ml/min/1.73m2) completed 20 minutes of walking at 60-70% VO2 peak. Venous blood samples were taken pre, post, and 1h post-exercise. Leukocytes and MPs were assessed using flow cytometry. Exercise increased classical (p = 0.001) and non-classical (p = 0.002) monocyte subset proportions but decreased the intermediate subset (p < 0.001) in all groups. Exercise also decreased the percentage of platelet-derived MPs that expressed tissue factor (TF+) in all groups (p = 0.01), though no other exercise-dependent effects were observed. The exercise-induced reduction in intermediate monocyte percentage suggests an anti-inflammatory effect, though this requires further investigation. The reduction in the percentage of TF+ platelet-derived MPs suggests reduced pro-thrombotic potential, though further functional assays are required. Exercise did not cause aberrant immune cell activation, suggesting its safety from an immunological standpoint (ISRCTN38935454).