Pauci-immune crescentic glomerulonephritis complicating Sjögren's syndrome in a 12-year-old girl

Dear Sirs,We read with great interest the article by Jung SK et al. onmesangial proliferative glomerulonephritis and IgA depos-its in a child with Sjogren's syndrome (SS) recentlypublished in Pediatric Nephrology[1]. The most commonform of renal involvement in SS is tubulointerstitialnephritis, generally causing mild renal dysfunction [2].Glomerulonephritis (GN) is rare with membranoprolifer-ative and membranous nephropathy being the mostcommonly described glomerular lesions, whereas cres-centic GN has been only occasionally reported in adults[3, 4]. Wefolloweda12-year-oldgirlwithprimarySS,whopresented with acute renal failure due to pauci-immunecrescentic GN with severe tubulointerstitial damage. Thepatient had a 7-year history of sicca syndrome withenlargement of both lacrimal glands and an abnormalSchirmer's test, pointing to the diagnosis of SS. At theage of 12 years, she presented with general malaise andthe biochemical signs of acute renal failure (creatinine9.5 mg/dl, BUN 103 mg/dl), oliguria (0.4 ml/kg/h),moderate proteinuria (1.23 g/l) and microscopic hematu-ria. Antistreptolysin O, anti-cardiolipin and lupus antico-agulant antibodies were absent. Viral serology (hepatitis Band C, HIV) was negative as well. Rheumatoid factor andC3, C4 complement levels were normal. Anti-DNAantibody titer measured by ELISA was 1:200. ANCA,ANA, and Anti-Ro/SS-A could be measured by immuno-fluorescence on the 90th day only. C-ANCA and p-ANCAwere negative, ANA titer (Hep-2) was 1:160 and Anti-Ro/SS-A were present (+).Renal biopsy contained 54 glomeruli, from which twowere completely sclerotic, four demonstrated fibrocellu-lar crescents, and all remaining glomeruli showed largecellular crescents (Fig. 1a). Tubulointerstitial inflamma-tion with patchy cellular infiltrates containing lympho-cytes, plasma cells, and monocytes was present (Fig.1b).Immunofluorescence with antibodies against IgG, IgA,IgM, C1q, C3, fibrinogen, κ and 1 light chains wasnegative.The patient received three pulses of methylprednisolone1,000 mg daily, followed by oral prednisolone 60 mg/day.Alternate-day plasmapheresis with substitution of 1 plasmavolume (x 4 times) and intravenous cyclophosphamidetreatment (750 mg/m