Plasma Cell-Rich Rejection and Worse Renal Outcomes After Kidney Transplantation: Simultaneous Histologic Evidence for Both Cellular and Humoral Rejection

BACKGROUND: Kidney transplantation is the optimal therapy for end-stage renal disease, but allograft rejection is considered to be a major obstacle to transplantation success. Plasma cell-rich rejection (PCR) is morphologically distinctive and may represent variants of allograft rejection, but the data remain limited. This study aimed to compare the clinical prognoses of different types of allograft rejection with that of PCR. METHODS: Between January 2002 and December 2017, there were 325 kidney transplant recipients with or without biopsy-proven rejection were divided into T cell-mediated rejection (TCMR), antibody-mediated rejection (ABMR), PCR, and other pathologic findings without evidence of rejection groups, and their histopathological lesions, allograft outcomes, and clinical prognoses were examined. The outcomes of interest included allograft loss and recipient survival. In addition, responses to different types of anti-PCR treatment were evaluated. RESULTS: Compared with recipients without rejection, recipients with mixed ABMR/TCMR were at greatest risk of allograft failure (adjusted hazard ratio [aHR], 3.70; 95% confidence interval [CI], 1.97-7.27), followed by those with ABMR (aHR, 3.07; 95% CI, 1.61-6.08), PCR (aHR, 3.07; 95% CI, 1.33-6.85) and TCMR (aHR, 2.47; 95% CI, 1.38-4.65). No significant difference in recipient survival after rejection was observed. Principal component analyses revealed that PCR was a morphologic type of combined cellular and humoral rejection. CONCLUSION: This study showed that PCR is associated with poorer allograft outcomes than is TCMR, but better outcomes than ABMR and mixed ABMR/TCMR. Therefore, clinical physicians need to be aware of this entity and apply more aggressive treatment strategies for kidney allograft salvage.