Alteration of IgG4 levels in cerebrospinal fluid in IgG4‐related disease

Dear Editor, Immunoglobulin G4-related disease (IgG4-RD) is an uncommon condition characterized by fibrosis and IgG4 lymphoplasmacytic infiltrates in diverse organs of unknown aetiology. Ig4-related pachymeningitis has been rarely described, but it can account for up to one-third of idiopathic hypertrophic pachymeningitis.1, 2 Dural biopsy is the gold standard for the final diagnosis. Pathological diagnostic criteria have been proposed by Lu et...