Kidney allografts with biopsy features of chronic mixed rejection reflect poorer survival than those with pure chronic antibody-mediated rejection D. Dobi, Zs. Bodó, É. Kemény, K. Bodaa, P. Szenohradszkyb, E. Szederkényib, B. Iványi Departments of Pathology, Medical Physics and Informaticsa and Surgeryb University of Szeged, Szeged, Hungary Introduction In late dysfunctional kidney allograft biopsies three rejection phenotypes can be observed: • chronic antibody-mediated rejection (AMR) • acute T-cell-mediated rejection (TMR) • chronic active TMR Chronic AMR: transplant glomerulopathy and/or transplant capillaropathy cg ptcml Acute TMR: interstitial infiltrates and tubulitis (interstitial rejection, ISR) with or without intimal arteritis Chronic active TMR: mononuclears in intimal fibrosis (cvmo) • Frequency: chronic AMR > acute TMR; chronic active TMR is exceptional • Chronic AMR and TMR may concur, termed chronic mixed rejection (CMR) Objectives To analyze • the histological patterns of chronic mixed rejection (CMR) • the clinicopathological relevance of the different patterns of CMR Material and methods • From 2001 to 2011, 61 biopsies displayed the histological features of chronic AMR (cg and/or ptcml ± C4d-positivity) • Luminex data were not avaible • Re-evaluation according to the Banff scheme (v, g, i, t, ptc, cg, ci,ct, ah) plus • Scoring of chronic arterial changes: mononuclears in intimal fibrosis (cvmo), intimal fibrosis (cvIF), intimal fibroelastosis (cvIFE); and tubular HLA-DR and ptcml • Staining of chronic active arteritis (cvmo) cases with CD3 and CD68 in adjacent sections • Two groups for clinicopathological analysis: purely CAMR vs CMR • Statistics: Spearman’s correlation, hierarchical cluster analysis, Kaplan-Meier estimator, Cox regression Results: main clinical data All patients (n=61) Purely CAMR (n=35) CMR (n=26) p Posttransplant time (months) 66±49 70±49 60±49 ns eGFR (ml/min/1.73 m2) 26±12 28±12 23±13 ns Postbiopsy follow-up (months) 23±22 26±22 19±20 ns Histological patterns 35 12 10 4 Chronic active TMR Purely CAMR Chronic active TMR and acute ISR CMR Acute ISR Features of chronic active arteritis CD3 Severe luminal narrowing (median score 3), mononuclears scattered throughout the fibrotic intima, T-cell predominance PAS CD68 Significant (p<0.05) and positive Spearman correlation coefficients between Banff scores and chronic arterial changes t HLA-DR cvmo ptc C4d g cg ptcml cvIF ci ct ah cvIFE i 0.769 0.606 0.347 0.301 0.264 t 0.654 0.2750.354 HLA-DR 0.363 cvmo ptc 0.3280.331 C4d 0.303 g 0.338 cg 0.258 ptcml 0.414 0.269 0.263 cvIF ci 0.806 0.299 ct ah cvIFE Hierarchical cluster analysis cvIF cvmo cvIFE 50 45 40 35 30 purely CAMR 25 20 CMR 15 -36 -33 -30 -27 -24 -21 -18 -15 -12 -9 -6 -3 -1 Bx +1 +3 +6 +9 +12 Mean eGFR value (ml/min/1.73 m2) Mean eGFR values in purely CAMR and CMR Time before (-) and after (+) biopsy (Bx) (months) Postbiopsy therapy Purely CAMR Therapy Steroid pulse CMR Chronic active CAMR Chronic active TMR and (n=35) TMR (n=12) acute ISR (n=4) 5 5 4 Acute ISR (n=10) 10 Intensification of maintenance immunosuppression 8 6 1 0 Anti-thymocyte globulin 0 0 2 0 Plasmapheresis 0 0 2 0 Left untreated 22 2 0 0 Mean graft survival in purely CAMR and CMR groups 50 vs 22 months Purely CAMR CMR p=0.011 Multivariable Cox regression of morphological variables HLA-DR cvmo ptc g cvIF cg ptcml ct ci cvIFE ah C4d CNI-tox. t i Discussion I. CMR was frequent in our series (43%) II. Chronic active arteritis appeared to be Tcell-related a. T-cell predominance in 14/16 cases b. Clustered with TMR lesions C. Lefaucheur et al. Antibody-mediated vascular rejection of kidney allografts: a population-based study. Lancet 2013; 381: 313-319. III. CMR was characterized by poorer allograft survival and more reduced allograft function than purely chronic AMR if chronic active arteritis was part of the TMR component IV. The immunohistochemical profiling of chronic active arteritis is recommended