Quantitation of IgG4+ Plasma Cells in Tubulointerstitial Nephritis.
Donald C Houghton, Megan L Troxell. Oregon Health and Sciences University, Portland
Background: IgG4-related tubulointerstitial nephritis (IRTIN) is a sclerosing lymphoplasmacytic inflammatory disorder that may affect the kidney alone, or may be part of the multi-system disorder, IgG4-related systemic disease (IRSD). Auto-immune pancreatitis (AIP) is the most common lesion of IRSD. The active inflammatory lesion in IRTIN is characterized by the presence of numerous IgG4+ plasma cells (IgG4+PC), but the specificity of this finding has not been determined. In this study we investigated the prevalence of IgG4+PC in renal interstitial infiltrates.
Design: We examined all renal biopsy samples with active interstitial inflammation, regardless of principal diagnosis, from 1/1/09 through 6/1/10, to determine the presence and extent of IgG4+PC in the infiltrates (N=100). Two observers independently scored each case for the density and extent of infiltrates, the apparent proportion of plasma cells, the extent and density of CD138+ plasma cells, and the distribution and numbers of IgG4+PC in the infiltrate.
Results: 29 cases were negative for IgG4+PC and 63 had fewer than 2 per high power field (hpf). The highest numbers of IgG4+PC were seen in some cases of diabetic nephropathy (DN), idiopathic interstitial nephritis (IISN), diffuse lupus nephritis (DLN), membranous glomerulonephritis (MGN), and necrotizing glomerulonephritis (NGN), including pauci-immune lesions, and those with granular and linear immune deposits:
|Diagnosis||# of IgG4+PC/hpf|