Finally, the significant allelic ratio variation of SLA-DRB1 in the amygdala, combined with its known importance in regulating pro-inflammatory cytokines (e.g., IL-1β, IL-6, TNF-α) and microglial activation (Harrison et al., 2009; Inagaki et al., 2012; Hu et al., 2022; Nazir et al., 2022), supports its involvement in immune regulation and stress-related mood disorders. This evidence concerns the gene IL6 and mood disorder.