IgG4-Related Disease Is Not Associated with Antibody to the Phospholipase A2 Receptor

Abstract EN

Patients with IgG4-related disease (IgG4-RD) share histopathological characteristics that are similar across affected organs.

The finding of infiltration with IgG4+ plasma cells in the proper clinical and histopathological contexts connects a large number of clinical entities that were viewed previously as separate conditions.

The renal involvement in IgG4-RD is usually characterized by tubulointerstitial nephritis, but membranous nephropathy has also been reported to be one of the renal complications of IgG4-RD.

The recent discovery that a high proportion of patients with idiopathic membranous nephropathy (IMN) have IgG4 autoantibodies to the M-type phospholipase A2 receptor (PLA2R) in the circulation and glomerular immune deposits, together with the profound IgG4 hypergammaglobulinemia and occasional reports of membranous nephropathy in IgG4-RD, raised the question of a common antigen.

To assess the presence of anti-PLA2R antibody in patients with IgG4-RD, we screened sera from 28 IgG4-RD patients by immunoblot.

None of the patients in this cohort had detectable circulating anti-PLA2R antibodies.

This study suggests that despite some clinical and serological overlaps between IgG4-RD and IMN,anti-PLA2R antibodies do not play a role in the pathogenesis of IgG4-RD.

Additional studies of IgG4-RD with evidence of membranous nephropathy are important to exclude any definite relationship.