CXCL8 and major depressive disorder: One explanation for slightly elevated IL-8 concentrations in BoDV-1 negative, but not in BoDV-1 positive MDD patients might be, that an activation of BoDV-1 in positive MDD patients may bypass the activation of the innate immune system and the release of pro-inflammatory and anti-inflammatory cytokines (Jordan and Lipkin, 2001; Reuter et al., 2010; Zhai et al., 2013).