A case of persistent acute allograft glomerulopathy with long-standing stable renal function

Acute allograft glomerulopathy (AAG) characterized by hypercellularity, enlargement of endothelial cells, infiltration of glomeruli by mononuclear cells and webs of PAS-positive material has been reported as an unusual but distinct form of acute rejection in kidney transplant recipients. We present a case of persistent AAG proven by serial biopsies. The patient was 53 years old when she received kidney transplantation from her mother. The immunosuppressants were methylprednisolone, azathioprine and FK506. She developed several acute rejections and received antirejection therapy. The patient transferred to our hospital 15 months after transplantation. Serum creatinine was 2.11 mg/dL. The level of serum creatinine was gradually elevated from 2.11 mg/dL to 3.09 mg/dL. Graft biopsy, performed 16.5 months after transplantation, represented prominent intraglomerular infiltration of mononuclear cells, segmental thickening of glomerular basement membrane (GBM) with double contour, grade 1 tubulitis, marked accumulation of mononuclear cells in peritubular capillaries and margination of mononuclear cells in a small artery. It was diagnosed as acute allograft glomerulopathy (AAG). Intravenous methylprednisolone pulse therapy, discontinuation of FK506 and administration of cyclosporin (CYA) resulted in decrease of serum creatinine. To evaluate histological evolution of AAG we performed two subsequent biopsies over 3 yr. Severe glomerulitis persisted as a prominent feature 8 months later and still existed 53.4 months after transplantation with decreased severity. The extent of GBM reduplication also decreased, but the percentage of glomerular sclerosis increased gradually. Multi-layering of basement membrane of peritubular capillary and interstitial fibrosis also increased. The prominence of infiltration of mononuclear cells in peritubular capillary was unchanged. At the last follow-up, i.e. 71 months after transplantation, her serum creatinine was 1.34 mg/dL. Neither proteinuria nor haematuria was observed. We consider that our immunosuppressive treatment has been successful so far, because the patient is still maintaining stable graft function since the transplantation over 6 yr ago. It is thus suggested that AAG per se probably has no influence on acute aggravation of graft function, but AAG and capillaritis in peritubular capillaries may cause an evolution of chronic allograft nephropathy, resulting in a slowly progressive deterioration of graft function.