Nevertheless, the ability of M. vaccae NCTC 11659 to increase Arg1 mRNA expression, as observed now both in vivo [12] and in vitro, may lead to a less aggressive M1-like inflammatory environment, which may be beneficial in some conditions, including neurodegenerative diseases [40,42,43] and psychiatric disorders [30]. This evidence concerns the gene ARG1 and neurodegenerative disease.