HLA-DRB5 and rheumatoid arthritis: The Reactome gene set analysis found an overlapping group of gene sets previously found by Wilcoxon and our test of rheumatoid arthritis, such modules containing the genes HLA-DRB5, HLA-DQA2, HLA-DRB1 : TCA signaling, PD-1 signaling, Interferon Gamma signaling, MHC class II antigen presentation (the latter also containing RACGAP1 and ITFG1).