Granulomatous interstitial nephritis in a renal allograft

Granulomatous Tubulointerstitial Nephritis in a Kidney Transplant Recipient: Case Report and Review of the Literature

BACKGROUND

Granulomatous tubulointerstitial nephritis (GTIN) is a rare pathologic finding on kidney biopsy. GTIN can be associated with drugs, infection, systemic granulomatous disease, and tubulointerstitial nephritis with uveitis syndrome. We present a case of GTIN in a kidney transplant recipient (KTR) and a literature review of published cases of GTIN in KTRs.

CASE PRESENTATION

A 65-year-old man with a history of pulmonary and ocular tuberculosis (TB), who had undergone deceased donor kidney transplant 8 years prior, was admitted for acute kidney injury, hypercalcemia, and uveitis. His medications included rifabutin, isoniazid, and tacrolimus. Serum laboratory tests revealed creatinine of 2.65 mg/dL (baseline 1.1-1.5 mg/dL) and corrected calcium of 13.2 mg/dL. Hypercalcemia workup showed parathyroid hormone 7 pg/mL, 1,25(OH) vitamin D 54 pg/mL, parathyroid hormone-related peptide <2.0 pmol/L, and angiotensin-converting enzyme 47 U/L. Kidney biopsy showed GTIN with noncaseating granulomas. Universal polymerase chain reaction testing for acid-fast bacilli, fungus, and bacteria was negative. He was treated with prednisone, and his kidney function returned to baseline, and his hypercalcemia resolved.

DISCUSSION

GTIN is a rare entity seen in less than 1% of transplanted kidney biopsies. The exactly etiology of this GTIN case remains unknown. TB could not be entirely ruled out, because the patient was receiving active anti-TB therapy. Our literature review showed infection to be the leading cause of GTIN in KTRs and that GTIN with concomitant uveitis remains exceedingly rare. Steroids may be useful in certain cases.

Sarcoidosis in the renal allograft of a recipient whose primary disease was autosomal dominant polycystic kidney disease

We report a 55-year-old man with a renal allograft that developed sarcoidosis. His autosomal dominant polycystic kidney disease (ADPKD) progressed to end-stage stage renal disease when he was 52 years old, and he underwent living-donor kidney transplantation at the age of 53 years. His proteinuria worsened at 19 months post-transplantation, and his renal function began to decline at 29 months post-transplantation. A renal allograft biopsy performed at 31 months post-transplantation revealed non-caseating granulomatous interstitial nephritis. The patient was treated with prednisolone (0.5 mg/kg/day), with gradual reduction in the dose. His proteinuria improved and renal function did not deteriorate any further. To the best of our knowledge, this is the first case of sarcoidosis in a renal allograft recipient whose primary renal disease was ADPKD.

Renal allograft granulomatous interstitial nephritis: observations of an uncommon injury pattern in 22 transplant recipients

Background: Granulomatous interstitial nephritis (GIN) is uncommon in native kidneys, and descriptions in allografts are few. We report clinical and pathologic findings in 22 allograft recipients with GIN identified in renal allograft biopsies and nephrectomies.

Methods: Renal allografts with GIN were retrieved from the pathology files of two academic medical centers. Available clinical and pathologic data were compiled retrospectively for a 23-year period.

Results: GIN was present in 23 specimens from 22 patients (15 males and 7 females) with allograft dysfunction [serum creatinine averaged 3.3 mg/dL (range 1.4–7.8)], at a mean age of 48 years (range 22–77). GIN was identified in 0.3% of biopsies at a mean of 552 days post transplantation (range 10–5898). GIN was due to viral (5), bacterial (5) and fungal (2) infections in 12 (54.5%), and drug exposure was the likely cause in 5 cases (22.7%). One had recurrent granulomatosis with polyangiitis. In 4 cases, no firm etiology of GIN was established. Of 18 patients with follow up data, 33.3% had a complete response to therapy, 44.5% had a partial response and 22.2% developed graft loss due to fungal and E. coli infections. All responders had graft survival for more than 1 year after diagnosis of GIN.

Conclusions: Allograft GIN is associated with a spectrum of etiologic agents and was identified in 0.3% of biopsies. Graft failure occurred in 22% of this series, due to fungal and bacterial GIN; however, most had complete or partial dysfunction reversal and long–term graft survival after appropriate therapy.