A recent study by Kang and colleagues demonstrated that the inducible expression of IL-18 in the mature murine lung induces pulmonary inflammation with the accumulation of CD4+, CD8+, CD19+ and NK1.1+ cells, emphysema, mucus metaplasia, airway fibrosis, vascular remodeling and right ventricle cardiac hypertrophy in B6 mice. This evidence concerns the gene CD4 and pulmonary emphysema.