IFNG and chronic obstructive pulmonary disease: For example, the variance in anti-trypsin was ~10 fold higher in the convalescence and exacerbated state compared to the stable state (Additional file 1: Table S3) IFNγ was found to correlate with IL-1α, IL-1β and IL-18 irrespective of exacerbation or baseline/convalescence, with Spearman’s rank rs values marginally higher during acute exacerbation of COPD (Additional file 2: Figure S1).