Clinicopathological and immunohistochemical analysis of plasma cell‐rich rejection in renal transplantation: Involvement of intratubular Th1/Th2 balance in plasma cell enrichment

ABSTRACT Aim Plasma cell‐rich rejection (PCRR) has been considered a subtype of acute T‐cell‐mediated rejection (ATCR). However, PCRR is recognized as refractory rejection and different from ATCR in various ways. In order to elucidate the pathogenesis of PCRR, we analysed PCRR clinicopathologically and immunohistochemically by comparing it with ATCR. Methods Twelve cases of PCRR (PCRRs) and 22 cases of usual ATCR (ATCRs) diagnosed at our hospital between January 2008 and March 2017 were included. Between PCRRs and ATCRs, we compared clinical data, Banff classification, graft outcome and the total sum number of T‐bet‐ and GATA3‐positive lymphocytes infiltrating in tubular epithelium using immunohistochemistry. Results Plasma cell‐rich rejections occurred later than ATCRs (median time after transplantation 1340.5 days vs. 52.5 days). Serum creatinine levels at discharge after treatment were significantly higher in PCRRs than in ATCRs (median 2.38 vs. 1.65 mg/dL). Cumulative rate of graft loss was significantly higher in PCRRs than in ATCRs (1‐, 2‐ and 5‐year: 26.7%, 51.1% and 51.1% vs. 0%, 0% and 17.5%). For profiles of Th1 and Th2, we found significantly lower ratio of T‐bet/GATA3‐positive lymphocytes in PCRRs compared with ATCRs. Conclusion This study suggests that PCRR is more refractory than ATCR and there are significant differences in populations of helper T‐cell subsets between them. We consider helper T‐cell subset analysis valuable for developing new treatment strategies for PCRR. SUMMARY AT A GLANCE The authors analysed plasma cell‐rich rejection (PCRR) clinicopathologically and immunohistochemically by comparing it with acute T‐cell‐mediated rejection (ATCR). The results suggested that PCRR might be recognised as a distinctive entity due to its poor prognostic behaviour and distinctive population of Th1/Th2 subsets.