Fig. 3

Relationships between IL-4-expression, smoking history and pulmonary elastin degradation. a Distribution analysis of CD4⁺ T-cells expressing IFN-γ versus CD4⁺ T-cells expressing IL-4. IL-4^highIFN-γ^low: COPD patients (n = 7) with more than 40% of CD4⁺ T-cells expressing IL-4. IL-4^lowIFN-γ^low: COPD patients (n = 11) with less of 20% of CD4⁺ T-cells expressing IL-4. b Relationship between IL-4^highIFN-γ^low and IL-4^lowIFN-γ^low subpopulations and exposure to tobacco smoke expressed as number of cigarettes per day for 1 year (pack-years). c Relationship between IL-4^highIFN-γ^low and IL-4^lowIFN-γ^low subpopulations and concentration of desmosine in the sera of COPD patients. *p < 0.05