Age-related features of the pattern of lymphocyte subpopulations and functional activity of peripheral blood mononuclear cells in patients with chronic kidney disease before and after transplantation

Abstract

Objective : to analyze the features of the pattern of lymphocyte subpopulations and the functional activity of peripheral blood mononuclear cells in older adult patients with chronic kidney disease. Materials and methods . The study featured 21 patients with chronic kidney disease (CKD), over 55 years of age, who underwent kidney transplantation (KT) from unrelated suboptimal donors. The average age was 61.4 ± 4.5 years (55 to 69). Comorbidity was assessed using the CIRS-G scale; the average number of points was 13.6 ± 5.09. The control group consisted of 21 volunteers, aged 55–70, without acute inflammatory diseases and signs of chronic kidney disease (CKD). The average age was 61.1 ± 4.4 years, the average CIRS-G score was 12.11 ± 6.04. In all patients, the pattern of lymphocyte subpopulations of peripheral blood was evaluated by flow cytometry. Vital computer laser cytomorphometry was used to assess the functional state of peripheral blood mononuclear cells. The Functional Activities Index (FAI) was evaluated to indirectly assess the degree of functional activity of cells. Results . In CKD patients before KT, there was a decrease in the proportion of CD4 cells (p = 0.009), an increase in the proportion of CD8 cells (p = 0.02), a decrease in the CD4/CD8 ratio (p = 0.017), an increase in the proportion of natural killers (p = 0.025) compared with healthy volunteers. Moreover, a decrease in the total proportion of CD3 cells, an increase in HLA-DR expression on CD3 cells, and an increase in the proportion of B cells were statistically insignificant: p = 0.137, p = 0.072 and p = 0.135, respectively. On the fifth day after KT, the proportion of CD3 cells increased (p = 0.017) mainly due to an increase in the proportion of CD4 cells (p = 0.002) compared to the pre- KT index. The proportion of natural killers (p = 0.002) and HLA-DR expression on CD3 cells (p < 0.0001) also increased. An increase in the proportion of CD8 cells and in the CD4/CD8 ratio, and a decrease in the proportion of B cells were statistically insignificant: p = 0.439, p = 0.277, and p = 0.236, respectively. A decrease in FAI was noted in patients with CKD before KT in comparison with healthy volunteers (p = 0.0138). After ATP, this indicator significantly increased compared to the pre-KT value (p < 0.0001) and exceeded the FAI value in healthy volunteers (p < 0.0001). In healthy volunteers, there was no significant correlation between the functional activity of peripheral blood mononuclear cells and age (r = –0.263 [95% CI –0.6236; 0.1907], p = 0.264, r2 = 0.069). At the same time, significant negative correlation between FAI and age was noted in CKD patients: r = –0.52 [95% CI –0.7771; –0.1135], p = 0.0157, r2 = 0.27 before KT; r = –0.418 [95% CI –0.7559; –0.06256], p = 0.0272, r2 = 0.175 after KT. Conclusion . Older adult CKD patients before and after KT were likely to have significant changes in the morphofunctional state of peripheral blood mononuclear cells and pattern of lymphocyte subpopulations. Moreover, the severity of changes in the functional state of these cells had a strong correlation with age, which was not observed in the group of healthy volunteers. This should be considered when choosing immunosuppressive therapy in older kidney transplant recipients.