S100B and major depressive disorder: Since S100B also has an immune-modulatory function (Donato et al., 2009) and immune dysregulation has been frequently described in major depression (eg, Miller et al., 2009; Zunszain et al., 2013; Carvalho et al., 2014; Grosse et al., 2015), it would be interesting to analyze how S100B relates to markers of the immune system.