Temporal IgG Subtype Changes in Recurrent Idiopathic Membranous Nephropathy

• Published in: American journal of transplantation Vol. 16; no. 10; pp. 2964 - 2972
• Main Authors: Kattah, A. G., Alexander, M. P., Angioi, A., De Vriese, A. S., Sethi, S., Cosio, F. G., Lorenz, E. C., Cornell, L. D., Fervenza, F. C.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Limited 01-10-2016
• Subjects: Adult; Aged; Autoantibodies - immunology; Biopsy; clinical research/practice; Female; glomerular biology and disease; Glomerulonephritis, Membranous - immunology; Humans; immune regulation; Immunoglobulin G - immunology; Kidney Transplantation; kidney transplantation/nephrology; Male; Middle Aged; pathology/histopathology; Recurrence; recurrent disease; Transplantation, Homologous; pathology/histopathology; glomerular biology and disease; recurrent disease; clinical research/practice; kidney transplantation/nephrology; immune regulation
• ISSN: 1600-6135; 1600-6143
• DOI: 10.1111/ajt.13806

Determination of the IgG subtypes within the immune deposits in membranous nephropathy (MN) may be helpful in the differential diagnosis. IgG4 is the predominant subtype in idiopathic MN and recurrent MN, while IgG1, IgG2, and IgG3 subtypes are more common in secondary MN and de novo disease in the allograft. The temporal change of IgG subclasses in individual patients and its correlation with clinical variables have not been studied. We reviewed all posttransplantation protocol and indication biopsies (49) in 18 patients with recurrent MN who underwent transplantation at our center between 1998 and 2013 and performed IgG subtyping (IgG1–4). We tested serum for M‐type phospholipase A2 receptor (PLA2R) autoantibodies or performed PLA2R antigen staining on the kidney biopsy. IgG4 was the (co)dominant IgG subtype in 10 of 14 biopsies at the diagnosis of recurrence regardless of PLA2R association. In 8 of 12 transplantations with serial biopsies, the (co)dominant subtype did not change over time. There was a trend toward IgG1 and IgG3 (co)dominance in biopsies >1 year from recurrence and more IgG1 (co)dominant subtyping in the setting of more‐advanced EM deposits. Treatment with rituximab did not affect the IgG subtype. In conclusion, the dominant IgG subtype did not change over time in recurrent MN.
In this study, the authors investigate the IgG subtypes in posttransplant biopsies of patients with recurrent membranous nephropathy and conclude that IgG4 is the dominant IgG subtype in these patients, regardless of time from recurrence or PLA2R association, and that the dominant subtype did not change over time in the majority of cases.