a b c d e Supplemental figure 4 Anti-human Igk + Igl CD34 Antibody-mediated rejection, active acute or chronic (ABMR) C4d + <10% + - DSA low + + + MICA+ C4d - + - - - DSA - - ND ND - Case 1 Case 2 Case 3 Transplant glomerulopathy without inflammation (TxGN) Nonspecific inflammation (NS) a c e b d C4d mostly - - <15% + - <15% + 20-25% DSA + ND ND + + + - + 184b 266a 322 234 233 334 343b 386 341 344 376 377 C4d - - - - - - DSA - - - - ND low + Acute cellular rejection (ACR) 181 235 348 349a 352 374 127b 239 245 351 343a 271b 238c nonspecific inflammation rejection focal mild rejection focal chronic rejection vascular rejection C4d+, DSA+ chronic rejection C4d+, DSA- 6 months 238b 6 weeks 271a 266b 12 months Supplemental figure 4 RMEC antibody binding in transplant biopsies. Gating: viable cells > CD45-/CD324-/HLA-DR+/CD31+ or CD34+. Representative dot plots of anti- l + k bound to RMEC in cases of a) antibody-mediated rejection, including active acute and chronic; b) transplant glomerulopathy without acute inflammation. Most of these kidneys had been transplanted over 20 years prior to biopsy with the exception of kidney 377. For case 377 the biopsy was done following treatment 5 months earlier for MHC class 1-related chain A (MICA) antibody-mediated rejection. c) Acute cellular rejection; d) non-specific inflammation where histologic conditions for rejection were not met (equivalent to Banff borderline). DSA and C4d information appear under each dotplot where results were available. Where a % is noted for C4d it reflects the pathologist’s estimate of amount of peritubular capillaries with C4d. In some cases DSA were not determined (ND) because either there was no clinical indication to do so or donor HLA type was unknown. In case 341 and 374, DSA were detected but below the level generally interpreted as positive by our HLA lab. In case 377, HLA DSA was negative but MICA antibody was detected. e) Dot plots of anti- l + k bound to RMEC from cases with serial biopsies. Clinical course for each case indicated by arrows and text below dot plot. In case 1 the biopsy initially showed nonspecific inflammation with no antibody binding; subsequently, when renal function worsened, antibodies bound to RMEC were detected. In case 2, a patient with persistent rejection six weeks after treatment showed continued RMEC antibody binding. In case 3 a patient with acute DSA+, C4d+ antibody-mediated rejection had slightly decreased levels of RMEC antibody binding following treatment, with resolution of DSA but persistent C4d+ tissue staining. Number in the lower left corner of the dot plots is the identifier code assigned to the biopsy. The positive level for combined lambda and kappa binding to RMEC, indicated by the vertical line on the dot plots, was set using the level of light chains detected on peripheral blood leukocytes from the same donor.