Expression of Receptor Activator of Nuclear Factor-Kappa B Ligand in Leukocytes During Acute Kidney Rejection After Transplantation in Rats

BackgroundAcute cellular rejection of the transplanted kidney is an important cause of impaired graft function. One of the basic characteristics of acute cellular rejection according to the latest Banff classification of renal allograft pathology is the presence of a large number of T lymphocytes in the allografted tissue. Osteoprotegerin, receptor activator of nuclear factor-kappa B (RANK) and RANK ligand (RANKL), three relatively novel members of the tumor necrosis factor superfamily, have crucial roles not only in physiologic and pathologic bone metabolism but also in immunologic processes. The aim of our study was to determine the expression of RANKL and RANK by T lymphocytes and macrophages in acute cellular kidney allograft rejection in rats.MethodsThe study included 15 male Wistar rats of 3 months old and 250–300 g as recipients and 15 male DA rats donors of 3 months old; and weight 250–300 g. When animals were sacrificed at 3 weeks to extract the transplanted kidney for pathohistologic analysis and immunoflorescence. all samples showed acute cellular rejection. Kidney sections were examined by dual-labeled immunofluorescence to detect CD4, CD8, or CD68 (red) and RANK or RANKL (green) with coexpressing cells as orange.ResultsRANKL-positive expression colocalized with CD4+ and CD8+ T lymphocytes in acutely rejected kidney tissue. There was no association between CD4+ and CD8+ T cells with RANK expression, which was evident by infiltrating CD68-positive macrophages in the kidney tissue interstitium.ConclusionRANK and RANKL were expressed by T lymphocytes and macrophages in acute cellular kidney rejection after transplantation in rats.