We performed eQTL mapping using CD4 T cells, CD8 T cells, B cells, monocytes, and neutrophils isolated from the peripheral blood of healthy volunteers (HVs) and patients with rigorously defined evidence of active inflammatory bowel disease (IBD: ulcerative colitis or Crohn’s disease) or anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). This evidence concerns the gene CD4 and anti-neutrophil cytoplasmic antibody-associated vasculitis.