Genes involved in immune and inflammatory responses and apoptosis were among the most highly upregulated and downregulated in MDD: BTNL8, CXCL8, LRIF1, NFKBIA, NLRC4, RGS1, RNASEL, TNFAIP3, and UBAP2L. Similarly, among the seven DEGs that were commonly identified in both our study and the public microarray data, the genes CD58, CXCL8, TARP, and TNFSF4 are also involved in immune and inflammatory responses. Here, BTNL8 is linked to major depressive disorder.