No evidence for production of intrathecal immunoglobulin G against Acinetobacter or Pseudomonas in multiple sclerosis.

The production of oligoclonal, polyspecific immunoglobulin G is characteristic of multiple sclerosis (MS), yet no pathogen has been identified as an infectious agent. Recent studies have proposed Acinetobactercalcoaceticus and Pseudomonas aeruginosa as candidate organisms, on the basis of a sequence homology between a bacterial enzyme and bovine myelin basic protein. To investigate this, we looked for specific, high-affinity immunoglobulin G against these pathogensin paired serum and cerebrospinal fluid from MS patients compared to other neurological diseases. We found no greater incidence of high-affinity antibodies against the organisms studied in MS vs. other neurological diseases, and so conclude that A. calcoaceticus and P. aeruginosa are unlikely to be implicated in the pathogenesis of MS.