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Abstract: FR-PO743

Clinical, Pathological, and Mass Spectrometry Analysis of AL Renal Amyloidosis

Session Information

Category: Glomerular

  • 1004 Clinical/Diagnostic Renal Pathology and Lab Medicine

Authors

  • Li, Mingxi, Peking Union Medical College Hospital, Chinese Academy of Medicine Sciences & Peking Union Medical College, Beijing, Beijing, China
  • Sun, Ying, Peking Union Medical College Hospital, Chinese Academy of Medicine Sciences & Peking Union Medical College, Beijing, Beijing, China
  • Wen, Yubing, Peking Union Medical College Hospital, Chinese Academy of Medicine Sciences & Peking Union Medical College, Beijing, Beijing, China
  • Chen, Limeng, Peking Union Medical College Hospital, Chinese Academy of Medicine Sciences & Peking Union Medical College, Beijing, Beijing, China
  • Li, Xuemei, Peking Union Medical College Hospital, Chinese Academy of Medicine Sciences & Peking Union Medical College, Beijing, Beijing, China
Background

In recent years, laser micro-dissection combined with mass spectrometry (LMD/MS) has been applied in the diagnosis of renal amyloidosis, it can be used for typing of amyloid deposits where routine immunohistochemistry (IHC) is equivocal and negative, as well as finding new causes of amyloidosis, In this study, we retrospectively analysis the patients with AL amyloidosis to evaluate the significance of immunoperoxidase (IP) and establish LMD/MS technique for diagnosing renal amyloidosis.

Methods

We analyzed 45 cases of AL amyloidosis patients diagnosed by Congo Red Staining (CRS) and EM who were admitted during last 5 years in a single centre, analyzed their clinical manifestations and pathological findings, then selected 20 cases with inconclusive immunofluorescence (IF) results, performed IP and LMD/MS for amyloid typing. For IP, both κ and λ were stained. For LMD/MS analysis, 7-μm sections were prepared and CRS positive area was collected by laser microdissection, the minimum area for each case was 200,000μm2. Sample microdissected was digested by trypsin. Peptides were quantified using Thermo Fusion Lumos mass spectrometer. MASCOT software was used for identification of proteins. Scaffold 4 software was used to integrate the results.

Results

Patients with AL renal amyloidosis had mutiple organs involvement, including kidney, liver, heart and intestinal system. Eleven (55%) of the 20 cases could be typed by IP technique. Amyloid materials could be identified in eighteen (90%) of the 20 cases by LMD/MS. Figure 1A and 1B were Mascot results of AL-κ and AL-λ amyloidosis subtyped by LMD/MS respectively .

Conclusion

Our study showed IP is superior to IF and MS-based proteomic analysis is complementary to IHC in typing of renal amyloidosis.

Funding

  • Government Support - Non-U.S.