IgG4-related kidney disease

PURPOSE OF REVIEW: IgG4-related disease (IgG4-RD) is a recently recognized systemic autoimmune disease that has received increased attention in the literature in the past several years. Renal involvement can take several forms, which are described in this review. RECENT FINDINGS: IgG4-RD may affect the kidney in various patterns. IgG4-related tubulointerstitial nephritis (TIN), presenting as either a mass lesion, renal failure, or both, has become an accepted manifestation of IgG4-RD. Two large series with biopsies and one clinical series of IgG4-related TIN have been published in the past two years; these series further delineate the clinical, laboratory, and pathologic features of this entity and propose diagnostic criteria. Glomerular disease in IgG4-RD, most commonly membranous glomerulonephritis (MGN), is becoming recognized as well. The first international conference on IgG4-RD was held in Boston, Massachusetts, USA, in October 2011; nomenclature and pathology consensus statements from this conference are forthcoming. In addition to better-defined clinical features of this autoimmune disease, in-vivo and in-vitro characteristics of the unusual IgG4 molecule have been studied further. SUMMARY: IgG4-RD should be considered as a cause of TIN or MGN in the appropriate clinical setting. An unresolved question is the role of the IgG4 antibody, if any, in the pathogenesis of this disease.