Myeloperoxidase (MPO)-Associated Vasculitis in a Kidney Transplant Recipient

Introduction: This is a case of catasthropic renal involvement of MPO vasculitis in a renal transplant patient. Case Description: 60 y/o female patient with a PMH of ESRD secondary to unknown etiology, received a second LRKT (sister) 1991, previous LRKT (father) in 1981, history of non-melanous skin cancer and vertigo. The patient presented to the emergency department due to rise in serum creatinine. She reported new onset bilateral joint pains (knees, shoulders and hip) which began 6 weeks prior. She denied fever, rash, cough, nausea, vomiting, diarrhea, confusion, shortness of breath or urinary symptoms. Her home immunosuppressive regimen consisted of Cyclosporine 100mg BID and Imuran 75mg daily. At evaluation, she has a blood pressure of 155/76 and heart rate of 84bpm. Physical examination revealed tenderness of bilateral knee, hips and shoulders. Baseline serum creatinine from 3 months prior was 0.8mg/dl. Serum creatinine upon admission was 4.6mg/dL and BUN 101md/dL. Urinalysis revealed 2+ protein, 3+ blood, 11-25/HPF WBC,>25/HPF RBC, 4-10/LPF hyaline cast. The urine protein creatinine ratio was 1.52g/g. Urine output was normal. The patient received IV fluids normal saline and serological work up C3,C4, complement def assay, dsDNA, ANCA, anti-GBM, hepatitis, HIV, cryoglobulin, haptoglobin were ordered. She was initiated on hemodialysis due to uremia. Kidney transplant biopsy light microscopy revealed acute crescentic glomerulonephritis. The patient was treated with 1g of IV solumedrol for 3 days and subsequent prednisone taper. The final biopsy report was Pauci-immune, necrotizing, crescentic glomerulonephritis, Interstitial fibrosis, 40 to 50%, and no evidence of rejection. Serological workup was positive for p-anca and myeloperoxidase antibody in concordance with the biopsy findings. The patient was treated with rituximab infusion while continuing to receive hemodialysis. However, there was no recovery in the renal function in the next 3 months in follow up and the patient remains on hemodialysis. Discussion: This is an interesting case of recurrence vasculitis with renal involvement in a kidney transplant patient. No triggering events were identified in her history, and the patient was compliant with her immunosuppresion regimen. The recurrence occured more than 20 years after transplant with catastrophic results, that is unusual for this disease.