The Many Faces of NELL1 MN.

Area of Science:

• Nephrology
• Immunology
• Pathology

Background:

• Neural tissue encoding protein with EGF-like repeats (NELL1) is a novel target antigen identified in membranous nephropathy (MN).
• Initial research suggested most NELL1-associated MN cases were primary, lacking secondary disease associations.
• Recent findings reveal NELL1 MN can occur in conjunction with various systemic conditions.

Purpose of the Study:

• To explore the expanding spectrum of diseases associated with NELL1-positive membranous nephropathy.
• To highlight the heterogeneity of underlying conditions linked to NELL1 MN.
• To emphasize the need for comprehensive etiological evaluation in NELL1 MN.

Main Methods:

• Review of existing literature and case reports on NELL1-associated membranous nephropathy.
• Analysis of clinical data linking NELL1 MN to secondary causes.
• Comparative assessment of primary versus secondary NELL1 MN presentations.

Main Results:

• NELL1 MN has been increasingly identified in association with malignancy, infections, autoimmune diseases, and drug exposure.
• Cases of NELL1 MN following hematopoietic stem cell transplant and in de novo kidney transplants have been reported.
• Sarcoidosis has also emerged as a potential comorbidity with NELL1 MN.
• This indicates significant heterogeneity in the underlying pathologies of NELL1 MN.

Conclusions:

• NELL1-associated membranous nephropathy is not exclusively primary and displays marked heterogeneity.
• The association of NELL1 MN with a wide array of conditions necessitates a more exhaustive search for underlying diseases.
• Further research is warranted to elucidate the mechanisms linking NELL1 to diverse pathologies in MN.