Since BAL is a far less invasive technique than tissue biopsy to study mechanisms in IPF we further investigated the usefulness offered by this means by studying the relationship between BAL macrophages, neutrophils, eosinophils, CD3+, CD4+, CD8+, CD8+/38+ TLs and CD4+/CD8+ ratio with breathlessness and physiological indices. Here, CD8A is linked to idiopathic pulmonary fibrosis.