In the group of patients with overlap syndrome, as well as in a general group of AILD, but not in patients with AIH, levels of IL-2 were significantly lower compared to controls (2.07 (range 0.11–111.87) in patients with AILD compared to 2.76 (range 0.45–4.10); p < 0.05). The gene discussed is IL2; the disease is overlapping connective tissue disease.