HLA-DRB1 and obesity due to melanocortin 4 receptor deficiency: On the other hand, genes important in complement activation (C1QB), cellular response to oxidative stress (MT2A, TXN, SGK1), lipid transport (APOE, CH25H), antigen presentation (HLA-DQA1, HLADRB1), and regulation of innate immune processes (KCNMA1, APOC1, IDO1) were upregulated in MAC_2 with pregravid obesity (Figures 4C, D).