Expression of chemokine receptors CXCR3 and CCR4 in lymphocytes of idiopathic nonspecific interstitial pneumonia

Abstract

Little is known about the role of chemokines and their receptors interaction, which are essential for recruitment of selective lymphocyte subsets during inflammation, in the pathogenesis of idiopathic nonspecific interstitial pneumonia (NSIP). Recent studies have revealed Th1 and Th2 cells preferentially employ the chemokine receptors, CXCR3 and CCR4, respectively, in the process of accumulation into inflammatory sites. We evaluated the CXCR3 and CCR4 expression on infiltrated lymphocytes in lung tissues of 12 NSIP cases and 10 idiopathic pulmonary fibrosis (IPF) cases in our previous study. The number of CXCR3 positive lymphocytes of NSIP patients was significantly greater than that of IPF patients (261.1+/-145.1 vs. 64.9+/-27.0, P<0.01). The number of CCR4 positive lymphocytes of NSIP patients was significantly lower than that of IPF (9.5+/-8.3 vs.62.6+/-26.9, P<0.01). The CXCR3 to CCR4 ratio of NSIP patients was significantly greater than that of IPF patients (47.9+/-45.9 vs. 1.11+/-0.40, P<0.01). The differences of CXCR3 positive, CCR4 positive lymphocyte counts, and of CXCR3/CCR4 ratio between cellular and fibrosing NSIP were not significant. These results suggest that a Th1 pattern of chemokine receptor expression predominates in the lung interstitium of patients with NSIP but, in IPF patients, CCR4 might be relatively predominant, in contrast to the finding in NSIP patients, and that Th1/Th2 balance might be an important factor in the pathogenesis of NSIP.