Circulating antibodies to conjugated tryptophan derivatives of IDO pathway in Amyotrophic Lateral Sclerosis, Alzheimer's disease, Parkinson's disease and Multiple Sclerosis patients.
Résumé
Tryptophan—kynurenine pathway is known to be involved in neurodegenerative disorders, such as amyotrophic lateral sclerosis, as well as Alzheimer's and Parkinson's disease. The activation of indoleamine 2,3-dioxygenase, an inducible enzyme, is able to increase the production of neurotoxic metabolites, such as quinolinic acid and 3OH-kynurenine. This report describes how isotype G, M, and A circulating immunoglobulins recognize a pattern of conjugated tryptophan metabolites from the IDO pathway in each pathology. Isotype A immunoglobulins were mainly found in amyotrophic lateral sclerosis and Alzheimer's disease. Conversely, isotype G, M, and A immunoglobulins increased in multiple sclerosis. In Parkinson's disease, statistically high antibody levels were obtained, but not a high percentage of positive patients. These data indirectly confirm the implication of tryptophan derivatives in the pathogenic processes of amyotrophic lateral sclerosis, Alzheimer's disease and multiple sclerosis. Further studies are required to evaluate the interest of these specific patterns in monitoring of each disease.