T Cell Phenotypes in Amyotropic Lateral Sclerosis (ALS), Influence of Vitamin D

ALS is a devastative disorder characterized by motor neuron degeneration. Median survival is 3 years after onset, but may vary from a few months to more than 30 years. Various factors have been suspected to play a role in such a variation, but recently, it has been described that regulatory T-lymphocytes (T regs) may mediate ALS progression and survival. Vitamin D is an hormone know to regulated T reg function in vivo and in vitro. It have recently demonstrated that vitamin D (VD) levels correlated with ALS prognosis and patients with a severe VD deficiency had a 6 time more rapid evolution than those with normal VD levels. The investigator want to go further in the study of the immune processes that could modulate prognosis in ALS. We propose 1- to study T cell phenotypes (Treg, CD4 (cluster of differentiation 4) -Th1, -Th17, -Th2, CD8 (cluster of differentiation 8)and NK) in ALS vs controls ; 2- In VD-deficient patients, to analyze the influence of a vitamin D supplementation on T cell phenotypes ; 3- to study the relationships between T cell phenotypes and ALS prognostic factors. The project will include 70 ALS patients and 27 controls in this prospective study. VD-deficient patients will be supplemented, according to national recommendations for 6 months, and the evolution of T cell phenotypes will be followed over 1 year. We hope to demonstrate first that T cell phenotypes in ALS are consistent with a pro inflammatory profile, compared to controls, secondly that VD treatment modulates T cell phenotypes towards a non-inflammatory one and, thirdly, that inflammatory T cell phenotypes correlate with a worse prognosis of the disease. This could allow proposing VD as a potential treatment of ALS in a future trial. More largely, this could reinforce arguments in favor of an immune intervention to attenuate the severity of this devastating disorder.