Species-specific accumulation of ceramides in cerebrospinal fluid from encephalomyeloradiculoneurpathy patients associated with peripheral complement activation: A pilot study

Glycolipids are now known to be rapidly converted to mediators for inflammatory reactions or to signaling molecules that control inflammatory events in the nervous system. The present study aimed to explore whether disturbed glycolipids metabolism in the nervous system is present in patients with a neuroinflammatory disorder, encephalo-myelo-radiculo-neuropathy (EMRN), because most EMRN patients have been reported to exhibit autoantibodies against neutral glycolipids. Although molecular pathogenesis of this disorder remains unknown, we tried to search the immunochemical abnormalities in this disorder. ELISA for activated peripheral C5 complement and mass spectrometry analysis of cerebrospinal fluid clearly disclosed a significant upregulation of active C5 complement, C5a levels in sera as well as a significant accumulation of species-specific ceramides but not sphingomyelin in cerebrospinal fluid from EMRN patients. Furthermore, we confirmed the occurrence of anti-neutral glycolipids antibodies in all EMRN patients. Thus, the present study might indicate the pathophysiology of this disorder is the dysregulation of glycolipids metabolism and abnormal production of autoantibodies against neutral glycolipids resulting in the abnormal complement activation, although molecular basis for these sphingolipids dysregulation and the occurrence of autoantibodies against glycolipids remains to be elucidated at present. The present study implicates a new therapeutic strategy employing anti-ceramide and/or anti-complement therapy for this disorder.