The regulatory/cytotoxic infiltrating T cells in early renal surveillance biopsies predicts acute rejection and survival.

Background: To analyze the immune phenotype of T-lymphocyte infiltrations in surveillance renal biopsies with stable renal function early post-transplantation (median time 40 days, range from 18 to 85 days).

Methods: One hundred and twenty-five surveillance biopsies with interstitial T-lymphocyte infiltration between non-atrophic tubules in the cortex (14 with subclinical rejection, 32 with borderline change and 79 with only interstitial T-lymphocyte infiltration but no obvious pathological abnormalities according to Banff criteria) were enrolled. All cases were classified into two groups: regulatory phenotype (RP) group, which was dominated by FOXP3-positive T lymphocytes in surveillance biopsies, and cytotoxic phenotype (CP) group, which was dominated by Granzyme B-positive T lymphocytes.

Results: The RP group includes 83.2% (104/125) cases, none of which developed acute rejection during nearly 5 years of follow-up. The CP group includes 16.8% (21/125) cases, all of which developed biopsy-proven acute rejection or clinical diagnostic acute rejection within 1 year after biopsy. Glomerular filtration rate and cumulative graft survival time were superior in the RP group than in the CP group (P<0.001).

Conclusion: Analyzing the immunophenotype of graft-infiltrating T cells in renal surveillance biopsies during early post-transplantation could predict acute rejection and survival.