Fig. 1

Kidney biopsy histopathology. Membranous-like glomerulonephritis with immune complex composed of galactose-deficient IgA1 (Gd-IgA1) in the patient with primary Sjögren’s syndrome. a Glomeruli showed diffuse bubbling appearance of glomerular basement membrane (periodic acid methenamine silver stain; original magnification, × 400). b Immunofluorescence (IF) for IgA showed granular deposition along glomerular capillary walls in addition to paramesangial areas (original magnification × 200). c IF for C3 showed the same pattern as IgA (original magnification × 200). d IF for Gd-IgA1 showed granular deposition along glomerular capillary walls with a pattern similar to those of IgA and C3. (original magnification × 200). For immunostaining, the primary antibody was anti-human Gd-IgA1 rat IgG monoclonal antibody from Immuno-Biological Laboratories (catalog no. 10777). e Ultrastructural studies showed electron dense deposits in the intra-membranous, paramesangial areas with diffuse thickening of glomerular basement membrane. Diffuse podocyte foot process effacement was also noted. (original magnification × 15000). f Electron dense deposits were also located in the subepithelial area (arrows). (original magnification × 25000). g IF for Gd-IgA1 in the small salivary gland evaluated at the diagnosis of pSS showed positive Gd-IgA1 staining of infiltrating lymphoplasmacytic cells. (original magnification × 200). h Negative control of IF for Gd-IgA1; the small salivary gland of a patient with pSS. (original magnification × 200)