IFNG and chronic obstructive pulmonary disease: Furthermore, the presence of anti-collagen V antibody in an ELISA assay, and collagen V-specific Th1 immune responses (IFNγ) (EliSpot assay performed on isolated peripheral blood mononuclear cells) has been demonstrated in the peripheral blood of patients with COPD and smokers, suggesting that Col V-specific autoimmunity is associated with cigarette smoking history and may be involved in the pathogenesis of COPD (17).