New 'Antigens' in Membranous Nephropathy

Area of Science:

• Nephrology
• Immunopathology
• Proteomics

Background:

• Membranous nephropathy (MN) involves immune complex deposition in the glomerular basement membrane.
• PLA2R and THSD7A antigens explain only about 60% of MN cases, leaving others unidentified.
• Unknown antigens in the remaining MN cases necessitate further investigation for diagnosis and classification.

Purpose of the Study:

• To identify novel target antigens in previously unexplained cases of membranous nephropathy.
• To characterize the distinct clinical and pathological features of newly identified MN types.
• To emphasize the role of mass spectrometry in diagnosing and classifying MN.

Main Methods:

• Utilized laser microdissection combined with mass spectrometry to identify unknown antigens.
• Analyzed protein structures, clinical presentations, and pathological findings of new MN types.
• Reviewed existing literature on PLA2R and THSD7A associated MN for comparison.

Main Results:

• Identified four novel types of MN associated with exotosin 1 (EXT1), exotosin 2 (EXT2), NELL1, Sema3B, and PCDH7.
• These represent distinct disease entities with unique clinical and pathological characteristics.
• Mass spectrometry proved crucial for accurate identification of these novel antigens and MN subtypes.

Conclusions:

• The identification of new antigens expands the understanding of membranous nephropathy.
• Classification of MN should be antigen-based, integrating newly discovered targets.
• Further research is essential to elucidate the pathophysiology, treatment response, and outcomes of these novel MN types.