C4A and diabetes mellitus: The STRING database analysis of genes associated with DR and in common with DM showed that C2, JUNB, RIOK3, HLA-DQA2, HLA-DRB5, AGER, HSPA1B, BAG6, CD8A, C4A, and TRIM10 are linked with the immune system process (Gene Ontology) with an FDR of 0.0198.