CD8A and idiopathic pulmonary fibrosis: Furthermore, previous studies of our group detected also a relationship between the MRC scale and tissue infiltrating CD8+ T lymphocytes as well as CD8+ T lymphocytes recovered by bronchoalveolar lavage [28,29] as well as a relationship between the MRC dyspnea and physiological parameters obtained during maximal and submaximal exercise testing known to reflect exercise limitation, disease severity and survival in IPF [30].