A potential pathogenic role of interleukin-6 in a child with ANCA-negative pauci-immune crescentic glomerulonephritis: case report and literature review

BACKGROUND: Crescentic glomerulonephritis is a disease characterized by severe glomerular injuries that is classified into five different pathological types. Patients with type V disease have pauci-immune crescentic glomerulonephritis (PICGN) that is negative for anti-neutrophil cytoplasmic autoantibodies (ANCAs). There are limited clinical data on the manifestations, treatment, and prognosis of type V crescentic glomerulonephritis, especially in children. CASE PRESENTATION: A 13-year-old girl who had an intermittent fever for more than 10 months was admitted to our hospital. She had no gross hematuria, oliguria, edema, or hypertension, but further tests indicated a decreased glomerular filtration rate, hematuria, proteinuria, and an elevated level of IL-6. The antinuclear antibody spectrum test was positive at 1:1000, and the ANCA and anti-glomerular basement membrane antibody tests were negative. A renal biopsy confirmed the diagnosis of ANCA-negative PICGN. We administered methylprednisolone pulse therapy with intravenous cyclophosphamide and oral mycophenolate mofetil. At the 3-month follow-up, her urine protein level was significantly lower, and her serum creatinine level was in the normal range. CONCLUSIONS: Fever may be an extrarenal manifestation of ANCA-negative PICGN, and IL-6 may play a role in the pathogenesis of this disease. Early methylprednisolone pulse therapy with an immunosuppressant may reduce symptoms and improve prognosis.