[Diagnostic value of IgG subtypes in membranous nephropathy: A case report]. / Place de l'étude des sous-classes d'IgG dans les glomérulonéphrites extramembraneuses : à propos d'un cas.

ABSTRACT

The study of immunoglobulin G subtypes constituting immune deposits present in membranous nephropathy is useful to guide diagnosis. IgG4 deposits are more often seen in primitive forms of membranous nephropathy due to autoantibody (anti-phospholipase A2 receptor in a majority of cases). These deposits are polytypic. In secondary forms, deposits are constituted of IgG1, IgG2 and IgG3. We report the case of a 52-year-old woman whose renal biopsy, done for glomerular proteinuria, shows membranous nephropathy with monotypic IgG4 deposits with no overt hematologic malignancy and no anti-PLA2R antibodies.