Recently it was shown that in Idiopathic Pulmonary Fibrosis (IPF) tissue infiltrating CD8+ T lymphocytes (TLs) are associated with breathlessness and physiological indices of disease severity, as well as that CD8+ TLs recovered by bronchoalveolar lavage (BAL) relate to those infiltrating lung tissue. This evidence concerns the gene CD8A and pulmonary fibrosis.