Annexin-1 is no useful surrogate marker of multiple sclerosis - an immunocytochemical study of the cerebrospinal fluid.

Objective: Annexin-1 is a calcium-binding protein with anti-inflammatory properties, which has previously been described in MS plaque tissue. We investigated the feasibility and specificity of annexin-1-immuncytochemistry of CSF cells to test its potential as a surrogate marker for MS. Materials and methods: CSF-specimens of 49 MS cases with different courses and 94 control cases were immunocytochemically studied with a monoclonal antibody to annexin-1. Results: The highest level of cytoplasmic immunoreaction was seen in the most acute inflammatory disorders, such as bacterial meningitis and neuroborreliosis. CIS-, RR-MS-, and viral meningoencephalitis cases came next. The lowest annexin-1 expression was observed in neurosyphilis and SP-MS. In PP-MS and non-inflammatory control cases, annexin-1 expression was entirely lacking. Conclusion: Immunocytochemical staining of CSF cells with an antibody to annexin-1 is feasible. This may be helpful in further study of its role in the pathophysiology of inflammatory CNS diseases. The expression pattern seems to rather reflect the acuteness of the inflammatory process than specifying a certain underlying pathology. Although differences were observed between diverse disease groups, because of considerable overlap, a certain diagnosis of an individual case cannot be achieved. Thus, at present, we cannot recommend annexin-1 as a reliable surrogate marker of MS.