Immunoglobulin G4 biomarkers and pathogenesis in immunoglobulin G4-related spinal pachymeningitis

Abstract

This letter to the editor highlights adding the diagnostic utility of immunoglobulin G4 (IgG4) measurements and its potential role in IgG4-related spinal pachymeningitis (IgG4-RSP) pathogenesis to the case reported by Chae TS et al, which focused on IgG4-RSP diagnosis based on magnetic resonance imaging findings and increased plasma IgG4 concentrations. A comprehensive understanding of both IgG4 serological and cerebrospinal fluid biomarkers is essential for managing this complex condition.

Keywords: IgG4-related spinal pachymeningitis; Serum IgG4; Cerebrospinal fluid IgG4; IgG4 indices; Pathogenesis

Core Tip: Immunoglobulin G4 (IgG4)-related spinal pachymeningitis is a rare inflammatory disorder affecting the spinal dura mater. Although increased serum IgG4 levels are commonly reported, they lack specificity when used in isolation. Cerebrospinal fluid-based biomarkers, such as the IgG4 indices and the presence of IgG4-specific oligoclonal bands, may provide a reliable alternative to meningeal biopsy, particularly when the latter is contraindicated or yields inconclusive results. These biomarkers offer advantages in terms of cost, accessibility, sensitivity, and specificity. Clarifying the pathogenic vs regulatory role of IgG4 is critical for both diagnosis and treatment.