Even a single, remotely positive post-transplant alloantibody test correlates with development of interstitial fibrosis/tubular atrophy and graft loss after kidney transplantation

Background: Chronic renal allograft loss is considered as immunologically mediated when donor-specific alloantibodies are detected.  However, remotely detected alloantibodies with lack of detection more proximate to graft loss occurrence may obscure the humoral association with graft damage. Methods: We retrospectively reviewed 609 patients multiply tested post-transplant for detectable alloantibodies and correlated their results with clinical outcomes. Results: Most patients had no detectable post-transplant alloantibodies (Group 1, n = 393), some converted from non-detectable to detectable alloantibodies (Group 2, n = 97), some always had detectable post-transplant alloantibodies (Group 3, n = 69), and some demonstrated alloantibodies that subsequently became undetectable (Group 4, n = 50). The incidence of death-censored graft survival for Group 4 patients was similar to Group 2 and 3 patients, and greater than Group 1 patients. Further, interstitial fibrosis/tubular atrophy (IF/TA) free survival was significantly worse (p=0.018) for Group 4 versus Group 1 recipients. Also, Group 4 versus Group 1 IF/TA-free survival was worse when recipients were regrouped based solely on anti-HLA class II (p=0.006), but not anti-HLA class I (p=ns) antibodies. Conclusions: Detectable anti-HLA antibodies, even remotely, post-transplant identifies recipients at greater risk for IF/TA associated graft loss when compared to patients without detectable alloantibodies.