In addition, elevation in IL-17A levels and decrease in IL-10 levels are described in COPD patients9,41, and IL-17/IL-10 ratio was associated with disease severity, as measured by % predicted FEV1 values in COPD patients41, suggesting that IL-17 deficiency is likely to be associated with impairment in physiologic measures. Here, IL10 is linked to chronic obstructive pulmonary disease.