Introduction

We are pleased to announce the publication of this supplement issue in Nephron, summarizing key lectures and presentations from the 26th and 27th Japanese Clinicopathological Conferences on Renal Allograft Pathology. Recent advances in medical technology pertaining to renal transplantation and an enhanced understanding of underlying pathophysiological mechanisms have contributed to an increase in novel research findings presented at these meetings. Additionally, numerous case reports addressing complex diagnostic and clinical management challenges were discussed.Highlights from the 26th meeting include Dr. Hotta’s lecture on the “Treatment and Early Diagnosis of Chronic Active Antibody-Mediated Rejection.” Other notable contributions comprise an assessment of globulin therapy for high-risk transplant recipients, a clinicopathological analysis of post-transplant collapsing FSGS, a case involving MICA antibody-associated antibody-mediated rejection, an instance of vascular endothelial cell injury in a patient receiving valproic acid, and a detailed review and discussion of plasma cell-rich rejection.Among the 27th meeting papers, “Banff 2022 Updated Classification of Renal Allograft Pathology” by Dr. Shimizu, “Prospects for Artificial Intelligence-Based Pathological Diagnosis of Renal Transplant Biopsy” by Dr. Iwadoh, and “Telepathology in Renal Allograft Pathology: Current Trends and Future Prospects” by Dr. Tsuchimoto are instructive for readers. Research papers such as the utility of the B-HOT panel for polyomavirus nephropathy, the significance of glomerular capillary C4d deposition with microvascular inflammation, and the clinicopathological investigation of medial smooth muscle cell atrophy in small arteries in kidney allografts are educational. In addition, there are some interesting case reports on PTLD and recurrent crystalline nephropathy.Collectively, these contributions are anticipated to provide substantial value to future clinical practice, diagnostic approaches, and research initiatives.