Renal allograft granulomas in the early post-transplant period

Granulomatous interstitial nephritis is an uncommon but potentially reversible cause of impaired kidney function. In the native kidney, granulomatous interstitial nephritis is commonly attributed to drug hypersensitivity, sarcoidosis, or tubulointerstitial nephritis and uveitis, with a significant fraction of cases labelled as ‘idiopathic’ [1]. In kidney transplant recipients, the incidence of interstitial nephritis has been reported to be <1% with only a fraction of these containing granulomas [2,3]. Although drug-related disease remains the most common aetiology of granulomatous interstitial nephritis, accurate diagnosis is particularly important in kidney transplant recipients due to concern over the consequences of altering immunosuppression in the early post-transplant period. Few published reports have described the evaluation and management of granulomatous interstitial nephritis in kidney transplant recipients, particularly in the immediate post-transplantation period. In the following report, we present three patients with granulomatous interstitial nephritis presenting within 3 months of kidney transplantation. All three are unique in their clinical presentation, pathological features, and outcome. In describing the cases, we illustrate the complexity of this issue and describe a measured approach to the diagnosis and management of granulomatous interstitial nephritis post-transplantation.