Background: Epithelial neutrophil-activating peptide 78 (ENA-78) and interferon gamma-inducible protein 10 (IP10) belong to the CXC chemokine family and are considered to be important factors in idiopathic pulmonary fibrosis (IPF). Idiopathic nonspecific interstitial pneumonia (NSIP) and IPF are the two largest subsets of idiopathic interstitial pneumonias (IIP). In patients with NSIP, the prognosis is generally good compared with IPF. Therefore, the pathogenesis of NSIP seems to be different from that of IPF, but this remains unclear. The aim of the present study was to evaluate the contribution of ENA-78 and IP10 in the two diseases.
Methods: We measured the levels of ENA-78 and IP10 in serum and bronchoalveolar lavage fluid (BALF) of patients with IPF (n=17), idiopathic NSIP (n=10) and healthy subjects (n=12) by enzyme-linked immunosorbent assays.
Results: The level of ENA-78 in BALF was significantly higher in IPF patients than in NSIP patients and controls. Serum levels of ENA-78 and BALF levels of IP10 in NSIP patients were significantly higher than in patients with IPF and controls. In BALF of patients with NSIP, IP10 level significantly correlated with the absolute number of lymphocytes. In IPF patients, BALF IP10 levels also correlated with the proportion of lymphocytes in BALF.
Conclusion: Our results show distinct profiles of CXC chemokines in IPF and NSIP, and suggest that these chemokines play an important role in inflammatory cell recruitment into the lung in patients with IIP.