[Aseptic meningitis in a patient with cerebrospinal fluid anti-agalactosyl IgG antibody-positive preclinical rheumatoid arthritis: a case report].

A 69-year-old woman presented with non-fluent aphasia, ideomotor apraxia, right hemiparesis and convulsion. Her medical history was unremarkable, and she had not suffered from arthritis. DWI and FLAIR image of brain MRI showed hyperintensities in the subarachnoid space along the left frontal and both parietal lobes, and these lesions were associated with gadolinium enhancement. The levels of serum anti-cyclic citrullinated peptide antibody, anti-agalactosyl IgG antibody and matrix metalloproteinase-3 were elevated. The results of blood cultures were negative. Cerebrospinal fluid (CSF) analysis revealed monocytic pleocytosis and negative findings for infection or malignancy. The level of anti-agalactosyl IgG antibody in CSF was elevated. The antibody index (AI) of anti-agalactosyl IgG antibody (the ratio between the CSF/serum quotient for IgG antibodies, and the CSF/serum quotient for total IgG; normal value of AI < 1.3) showed considerably high value of 8.4, indicating the intrathecal-specific antibody synthesis. As a result, the pathogenesis of her disease was consistent with rheumatoid meningitis despite lack of arthritis. After intravenous administration of methylprednisolone, her symptoms, the level of anti-agalactosyl IgG antibody in CSF, and the MRI findings were ameliorated. Anti-agalactosyl IgG antibody in the CSF was a helpful biomarker in diagnosis and assessment of the severity of rheumatoid meningitis.