Rheumatoid meningitis in the absence of active synovitis: A potential association of semaphorin 4A

Area of Science:

• Neurology
• Rheumatology
• Immunology

Background:

• Rheumatoid meningitis (RM) is a rare complication of rheumatoid arthritis (RA) that can occur even with inactive disease.
• Current diagnostic indicators for RM disease activity are lacking, and its underlying pathogenesis is poorly understood.
• This study explores the role of semaphorin 4A (Sema4A) in RM, particularly in cases without active synovitis.

Purpose of the Study:

• To investigate the potential association between rheumatoid meningitis (RM) and semaphorin 4A (Sema4A).
• To determine if Sema4A levels correlate with RM disease activity in patients with inactive synovitis.
• To explore the role of Sema4A in the pathogenesis of RM.

Main Methods:

• Case study of three patients with RM presenting with neurological symptoms and inactive synovitis.
• Measurement of serum and cerebrospinal fluid (CSF) Sema4A levels during acute and remission phases.
• Comparison of Sema4A levels in RM patients versus rheumatoid arthritis (RA) controls.
• Immunohistochemical analysis of Sema4A expression in RM leptomeninges.

Main Results:

• Patients with RM exhibited elevated serum and CSF Sema4A levels during the acute phase compared to remission.
• Serum Sema4A levels were significantly higher in RM patients than in RA controls (23.8 ng/ml vs. 7.48 ng/ml, p=0.014).
• Sema4A was detected in infiltrating cells and stromal tissues within the RM leptomeninges.

Conclusions:

• Serum and CSF Sema4A levels correlate with RM disease activity, even in the absence of active synovitis.
• Sema4A may serve as a potential biomarker for monitoring RM activity.
• Sema4A expression in the leptomeninges suggests a role in RM pathogenesis.