CD4 and amyotrophic lateral sclerosis: Naïve T CD4+ lymphocytes, primary regulators in the adaptive immune response, differentiate into subsets, like T helper (Th) 1, Th2, Th17, Th9, Th22, and regulatory T cells (Tregs) influenced by intracellular transcription factors and cytokines, the latter one with immunosuppressive functions and showing altered population in ALS, suggesting a role in modulating the immune response [7,8,9,10,11].