title: An Overlapping Case of Lupus Nephritis and IgG4-Related Kidney Disease.
abstract: We report a case of a 71-year-old Filipino female who was admitted to the hospital for abdominal pain, vomiting and diarrhea of 8 days duration. The patient was found to have marked acute kidney injury (AKI), which required hemodialysis in the next 3 days. Extensive workup revealed hematuria, subnephrotic range proteinuria, elevated anti-nuclear antibody (ANA) and elevated total immunoglobulin G (IgG) levels, with normal IgG4 and anti-dsDNA levels. On kidney biopsy, mild membranous glomerulonephritis was found, along with autoimmune tubulointerstitial nephritis (TIN) with a "full-house" pattern of immune deposits. These findings were suggestive of lupus interstitial nephritis. However, IgG4+ plasma cells were detected in the interstitium by immunostaining, favoring a diagnosis of IgG4-related kidney disease (IgG4-RKD). Our case highlights the difficulty in differentiating lupus nephritis (LN) from IgG4-RKD in some patients, raising the suspicion that these two entities can co-exist.
authors.affiliation: Department of Medicine, Staten Island University Hospital, Staten Island, NY, USA.
authors.forename: Mazen
authors.initials: M
authors.lastname: Zaarour
authors.affiliation: Department of Medicine, Staten Island University Hospital, Staten Island, NY, USA.
authors.forename: Chanudi
authors.initials: C
authors.lastname: Weerasinghe
authors.affiliation: Department of Medicine, Division of Nephrology, Staten Island University Hospital, Staten Island, NY, USA.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Eter
authors.affiliation: Department of Medicine, Division of Nephrology, Staten Island University Hospital, Staten Island, NY, USA.
authors.forename: Suzanne
authors.initials: S
authors.lastname: El-Sayegh
authors.affiliation: Department of Medicine, Division of Nephrology, Staten Island University Hospital, Staten Island, NY, USA.
authors.forename: Elie
authors.initials: E
authors.lastname: El-Charabaty
keywords: IgG4-related kidney disease; IgG4-related tubulointerstitial nephritis; Lupus nephritis; Membranous nephropathy; Tubulointerstitial nephritis