Open AccessMembranous nephropathy with masked polyclonal IgG deposits associated with primary Sjögren’s syndrome
Author(s) -
Kiyotaka Nagahama,
Aya Isomura,
Hiroaki Shimoyamada,
Shintaro Masuko,
S. Shimoda,
Miho Karube,
Yoshinori Komagata,
Shinya Kaname,
Junji Shibahara
Publication year - 2020
Publication title -
cen case reports
Language(s) - English
Resource type - Journals
ISSN - 2192-4449
DOI - 10.1007/s13730-020-00516-3
Subject(s) - membranous nephropathy , membranoproliferative glomerulonephritis , medicine , glomerulopathy , pathology , immunofluorescence , polyclonal antibodies , glomerulonephritis , autoantibody , nephropathy , nephrology , antigen , immunology , antibody , kidney , endocrinology , diabetes mellitus
Tubulointerstitial nephritis and renal tubular acidosis are well-known renal involvements with primary Sjögren's syndrome. However, several types of glomerulonephritis such as membranoproliferative glomerulonephritis and membranous nephropathy are also known to develop in patients with this syndrome. We here report a case of membranous nephropathy that developed 8 years after a diagnosis of primary Sjögren's syndrome in a female patient. Interestingly, the deposition was not identified by routine immunofluorescence using snap frozen tissue, but was revealed by immunofluorescence on formalin-fixed paraffin-embedded sections treated with proteinase K. We further performed immunofluorescence analysis on the treated paraffin-embedded sections with the identified antigen but found that the deposited IgG was not monoclonal and that serum amyloid P, a sensitive marker for membranous-like glomerulopathy with masked IgG κ deposits, was not evident in the glomeruli. To the best of our knowledge, this report depicted the first case of masked polyclonal IgG deposits and further analysis is needed to clarify the underlying mechanisms of IgG masking and possible association with autoantibodies.