CHANGES OF CD4CD28NULL AND CD8CD28NULL T CELLS IN CHRONIC KIDNEY DISEASE AND THE IMPACT OF DIFFERENT DIALYSIS MODALITIES

Abstract Background and Aims Chronic Kidney Disease (CKD) affects both the innate and adaptive immunity, although clinical consequences, and the effect of different renal replacement methods on those alterations remain unclear. The purpose of this prospective observational study was to investigate the alterations of T cell immunity in CKD patients, as well as the effect of different dialysis methods on T lymphocyte subtypes. Method T cell subpopulations namely CD3+CD4+, CD3+CD8+, CD4+CD28- and CD8CD28- cells, were isolated from whole blood samples using flow cytometry in 40 CKD patients at predialysis state (ESRD-T0). The immunological profile was repeated six months later after initiation of renal replacement therapy (hemodialysis (HD) or peritoneal dialysis (CAPD)). Fifteen age and gender matched healthy individuals served as controls. Results Both CD4+ and CD8+ T cells were significantly reduced in ERSD-T0 patients compared to controls, 604(105-3551) vs. 943(584-1867) μ/L, p=0.001, and 352(103-1561) vs. 422.4(263-1453) μ/L, p=0.05. The percentage of both CD4+CD28null and CD8+CD28null cells, 6.4(0.3-30) % vs. 2.7(0.1-7.8) %, p=0.04 and 58.2(12.8-85.4) % vs. 39(7.8-57.1) %, p=0.01 was increased in ERSD-T0 patients comparing to controls. Furthermore the percentage of CD4+CD28null cells correlated with CRP (r=0.4, p=0.04) and serum albumin levels (r=-0.5, p=0.007), while, significant differences were noticed between patients with and without cardiovascular disease, regarding both, CD4+CD28null and CD8+CD28null cells, 8.6(1-30) % vs. 2.1(0.1-19.8) %, p=0.04 and 62.5(12.8-85.4) vs. 45.5(5.7-73.7), p=0.02, respectively. Changes in the population of CD4+CD28null after 6 months on dialysis showed significant differences between HD and CAPD methods, 110.11(-27.1 to 311.4)% vs. -28.1(-100 to 30)%, respectively, p=0.003, as were in CD8+CD28null cells, 55.23(-29.06 to 197.93)% vs. -8.34(-54.99 to 66.72)%, respectively, p=0.05. Conclusion CKD seem to affect specific T cell subtypes, at a pre-dialysis stage, and levels correlate with chronic inflammatory markers and the presence of CVD. These disturbances are further enhanced in HD, while they are alleviated in CAPD.