Indicators of monocyte-derived component of the immune system in patients with satisfactory renal graft function

Abstract

Objective: to study the indicators of the monocyte-derived component of the immune system in kidney transplant recipients with satisfactory early and delayed renal transplant function. Materials and methods. The study involved 76 kidney transplant recipients. Concentrations of serum creatinine (sCr), serum urea (sUr) and serum cystatin C (sCysC) were measured. CD14+mid/high and CD14+low were isolated from CD14+ monocytes. CD64- and CD86-expressing cell counts were determined for each subpopulation. Immunological examination was performed before surgery, as well as at days 1, 3, 7, 30, 90, 180 and 360 after surgery. Results. There was significant imbalance between the two monocyte subpopulations before transplantation and in the early post-transplant period (first 3 months). By the end of a 6-month follow-up period, the percentage of CD14+ cells had normalized. The dynamics of the subclasses of CD86-expressing monocytes in the post-transplant period is somewhat different from the dynamics of the total count for these monocytes. However, by the end of a 6-month follow-up period, these biomarkers returned to normal for the group of healthy individuals (CD14+mid/highCD86+ p180 = 0.079; CD14+lowCD86+ p180 = 0.789). CD14+lowCD64+ level was significantly higher in the kidney transplant group than in the control group during the entire follow-up period (p0 = 0.0006, p1 = 0.0001, p7 = 0.005, p30 = 0.005, p90 = 0.007, p180 = 0.0002, p360 = 0.001). On the other hand, CD14+mid/highCD64+ count for up to 180 days was not significantly different from that of the control group (p0 = 0.561, p1 = 0.632, p7 = 0.874, p30 = 0.926, p90 = 0.912), with subsequent significant increase by day 360 of follow-up (p180 = 0.01, p360 = 0.003). We observed a negative correlation between CD14+lowCD86+ level at day 0 and sCr levels at day 7 (r = –0.4; p = 0.008) and day 360 (r = –0.34; p = 0.042) and sCysC level at day 7 (r = –0.57; p = 0.014). A negative correlation was also found between CD14+lowCD86+ at day 1 and sCr levels at day 7 (r = –0.4; p = 0.005) and day 360 (r = –0.39; p = 0.02). There was positive correlation between the CD14+lowCD64+ subpopulation index at day 0 and sCr (r = 0.54; p = 0.008) and sCysC (r = 0.6; p = 0.008) levels at day 7, and also between the CD14+lowCD64+ count at day 1 and sCr (r = 0.55; p < 0.0001) and sCysC (r = 0.58; p = 0.004) levels at day 7. CD14+mid/highCD64+ at day 0 negatively correlated with sCysC level at day 360 (r = –0.85; p = 0.015), while CD14+mid/highCD64+ at day 7 positively correlated with sCysC level at day 360 (r = 0.50; p = 0.016). Conclusion. Before transplant surgery, CD14+mid/high, CD14+mid/highCD86+ , and CD14+lowCD86+ counts were reduced, while those of CD14+low, CD14+mid/highCD64+ and CD14+lowCD64+ were increased. By the 6-month follow-up, all these subpopulations except CD14+mid/highCD64+ had reached values for healthy people. Positive correlation between CD14+mid/high, CD14+lowCD64+ , CD14+mid/highCD86+ , CD14+mid/highCD64+ counts in the early post-transplant period and sCr/sCysC levels in long-term follow-up, as well as negative correlation between CD14+low, CD14+lowCD86+ counts in the early post-transplant period and sCr/sCysC levels in long-term follow-up can serve as a predictor of renal graft function.