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Abstract: PO2322

IgG4-Related Disease: Nephropathy and Bone Marrow Failure in a 2-Year-Old Child

Session Information

Category: Trainee Case Report

  • 1700 Pediatric Nephrology

Authors

  • La Porta, Edoardo, Istituto Giannina Gaslini, Genova, Liguria, Italy
  • Pisani, Isabella, Ospedale Universitario, Parma, Italy
  • Faraci, Maura, Istituto Giannina Gaslini, Genova, Liguria, Italy
  • Pilato, Francesco Paolo, Ospedale Universitario, Parma, Italy
  • Lanino, Luca, Ospedale Policlinico San Martino, Genova, Liguria, Italy
  • Verzola, Daniela, Ospedale Policlinico San Martino, Genova, Liguria, Italy
  • Garibotto, Giacomo, Ospedale Policlinico San Martino, Genova, Liguria, Italy
  • Sementa, Angela R., Istituto Giannina Gaslini, Genova, Liguria, Italy
  • Gnetti, Letizia, Ospedale Universitario, Parma, Italy
  • Verrina, Enrico E., Istituto Giannina Gaslini, Genova, Liguria, Italy
Introduction

IgG4 related disease (IgG4 RD) is a systemic immune-mediated disorder that can potentially affect every organ. It is characterized by fibro-inflammatory tissue damage, IgG4 positive plasma cells, and often by elevated serum IgG4. Renal involvement can include tubulointerstitial nephritis (TIN), membranous glomerulopathy (MGP), and retroperitoneal fibrosis. The disease is more frequent over 50 years of age and only a few cases of IgG4 RD are reported in children.

Case Description

A 2-year-old child was diagnosed with a trilinear bone marrow failure. Bone marrow biopsy showed poor and dyshomogeneus cellularity and lymphoplasmacytic infiltrate organized in follicular structures. Hematologic DNA analyses were negative. IgG subclass analysis showed elevated serum levels of IgG4 subclass (353 mg/dL). Kidney failure was also found (creatinine 1.3 mg/dL, microhematuria, proteinuria, and granular casts). A renal biopsy was performed. Light microscopy showed tubulointerstitial inflammatory infiltrate, thickening of the glomerular basement membranes, and subepithelial deposits C4d. IF showed subepithelial glomerular IgG deposits with granular pattern and tubular wall deposits; C3 glomerular deposits and focal tubular deposits. A diagnosis of MGP associated with TIN was made. IHC staining for IgG4 demonstrated plasma cells with overlapping positivity for IgG and IgG4. After the diagnosis of IgG4 RKD, a therapy with steroids was started, without clinical response. Thereafter the patient underwent to bone marrow transplant.

Discussion

IgG4 RKD in adults with simultaneous TIN and MGP has been reported in a few cases. This is the first documented case of IgG4 RKD with simultaneous TIN and MGP in a pediatric patient. IgG4 RD is an emerging systemic disease and it should be taken into account in the differential diagnosis in systemic autoimmune diseases, also in pediatrics.