TNF and depressive disorder: We were also interested in examining IL1β (−511C>T, rs 16944, Dixon et al., 2007) and TNF (-308G>A, rs1800629, Abraham and Kroeger, 1999; McGuire et al., 1994; Nadel et al., 1996, but see Bayley et al., 2004) as moderators of the stress-depression relationship, based on their association with changes in pro-inflammatory cytokine expression, and preliminary evidence of their relevance to mood symptoms.