Functional assessment of immune markers of graft rejection: a comprehensive study in live‐related donor renal transplantation

Abstract

A better understanding of the immunobiological processes and predictors of graft rejection holds promise for the development of potential therapeutic strategies and also individualization of immunosuppression. The objective of this study is to analyze the clinical relevance of immune parameters such as antidonor antihuman leukocyte antigen (anti-HLA) antibodies, monitoring of cytokines and their receptors on the graft outcome following live-related donor renal transplantation. Flow cytometry-based methods were used to detect antidonor antibodies (flow cytometry crossmatch, FCXM) and intracellular cytokines. Enzyme-linked immunosorbent assay (ELISA) methods were employed to detect anti-HLA class I and class II antibodies and quantitative serum-soluble interleukin-2 receptor (sIL-2R) levels. The data revealed that patients with HLA class I-specific IgG antibody experienced higher acute rejection (AR) episodes at 1 yr in comparison to the antibody negative group (82% vs. 56%, p = 0.01). On the contrary, donor-specific class II antibodies (B+) did not have any influence on the graft survival. However, 15 recipients having both T- and B-cell antidonor antibodies (T+B+) had significantly poor graft survival (60%) as compared to the antibody-negative group (T-B-, 82%, p = 0.05). Additionally, patients having non-donor but HLA-specific antibodies (FCXM-/ELISA+) had poor graft survival as compared to the antibody-negative group (64% vs. 88%, p < 0.05). Further, patients undergoing AR episodes had significantly higher expression of IFN-gamma-producing T cells (19.16 +/- 7.4% median 17.50) as compared to their pre-transplant levels (5.68 +/- 1.63%, Median 5.20) and the non-rejecter group (5.97 +/- 4.39%, median 4.3, p = 0.0004). Similarly sIL-2 was significantly increased in AR episodes during the first month of transplantation (292 +/- 131.5 pmol/L) as compared to those with well-functioning grafts (p = 0.01) and healthy controls (p = 0.001). Evaluation of antidonor antibodies by flow cytometry is found to be relatively more sensitive and a better predictor of graft outcome. Further monitoring of cytokine expression profile of primed peripheral T-helper cells and quantitative analysis of sIL-2R offer additional valuable diagnostic and prognostic tools for follow-up of transplant subjects and a better alternative for functional assessment of immunosuppression.

Serum Soluble Interleukin 2 Receptor Level as a Marker of Acute Rejection in Pediatric Kidney Transplant Recipients

“…In all these studies, pre- and post-TX serum measurement of sIL2R were undertaken and correlated in relation to each other and in some of them with healthy controls. All had agreed that sIL2R levels went up during the rejection episodes to mean values, which is significantly higher than their pre-TX levels as well as that observed in normal healthy controls [10, 13, 15]. However, this point might be compensated by the larger number of patients who experienced AR in our study compared to other studies.…”

“…Our study lacked the benefit of sequential analysis of levels of sIL2R, as was done in each of Mehta et al [10], Panigrahi et al [13] and Rasool et al [15], studies. In all these studies, pre- and post-TX serum measurement of sIL2R were undertaken and correlated in relation to each other and in some of them with healthy controls.…”

“…Each of Gupta et al [2], Mehta et al [10], Panigrahi et al [13], Garcia-Roca et al [14], and Rasool et al [15], studies suggested that the patients experiencing acute renal allograft rejection showed higher concentration of serum sIL2R at various periods after transplantation, as compared to patients with stable graft functions, and the rise was statistically significant [4, 10, 13-15]. In the study of Garcia-Roca et al [14], levels of sIL2R in patients with BPAR were compared to its level in patients with graft dysfunction due to causes other than AR in addition to comparing it with patients with stable graft function, and they found that sIL2R levels increased significantly in patients during AR compared to patients with other causes of graft dysfunction or stable graft function.…”

High negative predictive value of an amplified flow cytometry crossmatch before living donor kidney transplantation

“…Previous studies yielded contrasting results, describing an association of a positive FCXM result with (antibody-mediated) allograft rejection [3,4,11,13] or allograft loss [3,5,11,12], or, by contrast no association with allograft rejection [6 -10] or allograft loss [7,8]. These discrepancies possibly result from differences in the FCXM procedure or analysis or from differences in patient care.…”

Lymphocyte surface molecules as immune activation biomarkers

“…An elevated ratio of posttransplant to pre-transplant sIL2r concentrations was reported in kidney transplanted patients with acute rejections compared with those without rejection in two separate studies [71,72]. In contrast, in another study with heart transplant recipients, higher sIL2r concentrations were observed in severe rejection patients [73].…”