The development of natural antibodies (Nabs) in the absence or presence of donor-specific antibodies (DSA) is associated with poorer graft survival and worse microvascular injury. (A) Kaplan–Meier curve depicting 7-year graft survival of Nabs−/DSA−, Nabs−/DSA+, Nabs+/DSA−, and Nabs−+/DSA+ kidney transplant recipients. Histologic examination of biopsies performed at 1 year post-transplant or the time of rejection within the first year are shown as mean Banff scores for (B) microvascular inflammation, (C) C4d deposition, (D) transplant glomerulopathy, (E) interstitial inflammation and tubulitis, (F) interstitial fibrosis and tubular atrophy, and (G) arteriosclerosis. Renal function was assessed and is shown as (H) mean eGFR and (I) mean proteinuria.