Acute rejection is a major cause of graft loss in patients with kidney transplantations. However, the appropriate timing for performing a biopsy is often difficult to gauge in a clinical settings. We encountered an 8-year-old boy in whom antibody mediated rejection (AMR) associated with de novo donor-specific antibody (DSA) developed shortly after an episode of type IA acute cellular rejection (ACR). He had received a preemptive ABO-compatible kidney transplantation due to bilateral renal hypoplasia. Type IA ACR developed 2 months after transplantation and was successfully treated with methylprednisolone pulse therapy (MPT) and gusperimus hydrochloride. However, 4 months after transplantation, his serum creatinine level increased again. We decided to perform an additional biopsy despite having done the previous biopsy only a short time ago. Marked infiltration of inflammation cells in the peritubular capillaries (PTCs) with positive C4d staining was observed. AMR associated with de novo DSA with type IB ACR was newly diagnosed because DSA was not detected and the crossmatch test was negative before transplantation. He immediately received two courses of plasma exchange (PE), three courses of MPT, and rituximab. He confessed to non-adherence and underwent a patient education program with his family again. To date, no cases of AMR associated with de novo DSA shortly after ACR have been reported. Our experience lends support to the 'episode biopsy' method in which a biopsy is performed for each episode of serum creatinine increase as recommended by The Kidney Disease: Improving Global Outcomes (KDIGO) Transplant Working Group.
Keywords: Antibody mediated rejection; De novo donor-specific antibody; Kidney transplantation.