Peripheral lymphocyte subsets in acute cellular rejection in living donor liver-transplant recipients: A prospective observational study

Introduction: The aim of the study was to assess the peripheral blood lymphocyte subsets as immune markers for acute cellular rejection (ACR) in the living donor liver-transplant (LDLT) recipients using high-dimensional flow cytometry. Materials and Methods: This is a prospective observational study in which 19 LDLT recipients undergoing liver biopsy for suspected rejection were enrolled after informed and written consent. They were divided into two groups as rejection group (11/19) and no rejection group (6/19). In addition to this, nine healthy subjects were also enrolled as controls. Biochemical and immune parameters were analyzed among these groups. Results: It was observed that hematocrit, total protein, and serum albumin levels were significantly higher in rejection group as compared to no rejection group (P = 0.021, 0.006, and 0.044, respectively), whereas aspartate transaminase was significantly lower in rejection group compared to no rejection group (P = 0.027). It was seen that central memory (CM) helper T (T-H) cells and CM cytotoxic T (T-C) cells were significantly lower in no rejection group when compared to healthy controls (P = 0.02 and 0.009, respectively). The effector T-H cells and TH1 cells were significantly higher in the rejection group when compared to healthy controls (P = 0.03 and 0.04, respectively). However, the effector CD8+ T cell and memory B cell subsets were significantly higher in rejection and no rejection group compared with healthy controls (P = 0.03, 0.01 and P = 0.02, 0.009 respectively). The activated regulatory T cells (T-REG) and plasmablasts were significantly higher in no rejection group when compared with healthy control (P = 0.038 and 0.016, respectively). The naive B cells were significantly lower in rejection and no rejection group compared to healthy controls (P = 0.001 and 0.01, respectively). However, when immune profile was compared among the rejection and no rejection group, we could not arrive at statistically significant results owing to the small sample size. Conclusion: The data in this study show that there is difference in immune profile of lymphocyte subsets among rejection and no rejection groups compared to healthy controls and hence can be used to characterize these patients. The promising immune subsets that can serve as biomarkers for ACR post-LDLT are T(H)1 cells, CM TH cells, effector T-H cells, CM T-C cells, effector T-C cells, activated T-REG cells, naive B cells, memory B cells, and plasmablasts.