Plasma cell infiltrates and renal allograft outcomes in indigenous and non-indigenous people of the Northern Territory of Australia

Introduction: Plasma cell-rich rejection is a distincthistological phenomenon associated with poor renal allograft outcomes.Aboriginal and Torres Straight Islander (ATSI) transplant recipients havepoorer allograft survival and higher rates of acute rejection. We sought todetermine whether a higher incidence of plasma cell-rich infiltrates (PCIR)could account for poorer survival.

Methods: Renal transplant biopsies performed in recipients from theNorthern Territory of Australia between 1985 and 2007 were reviewed and correlatedwith outcome. Biopsies were designated PCIR positive when plasma cellsconstituted >10% of the interstitial infiltrate.

Results: Four hundred and seventy-seven biopsies from 177 recipients(108 ATSI) were performed. Median graft survival was shorter for recipientswith PCIR: 4.0 years (interquartile range 2.18-6.41) versus 5.4 years(2.0-9.99) (P = 0.013). ATSI recipients had higher rates of plasma cell-richrejection (RR 1.76, 95% CI 1.43-2.17, P< 0.0001), which occurred earlier(251 vs 869 days, P = 0.03) compared with non-indigenous recipients. Onmultivariate analysis, PCIR did not independently influence allograft survival.There was a correlation between PCIR and panel reactive antibody peak >20%(RR 1.29, 95% CI 1.03-1.56, P = 0.025), ≥5 human leukocyte antigen mismatches(RR 1.91, 1.41-2.58, p< 0.0001), increasing post-transplant infection rate(>10 infections RR 5.11, 1.69-15.5, P = 0.004), and subsequent death fromsepticaemia (RR 1.6, 1.17-2.18, P = 0.003).

Conclusion: PCIR is associated with infection and markers ofchronic immunological stimulation but does not independently contribute toinferior renal allograft outcomes, even in ATSI recipients.