Pathogenesis of cBFL in common with IPF? Correlation of IP-10/TARC ratio with histological patterns

¹ Tokyo Medical and Dental University, Japan
² Tokyo Medical and Dental university, Japan

^* To whom correspondence should be addressed. E-mail: yoshizawa.pulm{at}tmd.ac.jp.

Accepted 24 January 2008

	Abstract

Background: A Th1 predominant immune response has been shown in acute hypersensitivity pneumonitis. A Th2 predominance appears to favor the development of pulmonary fibrosis through the profibrotic process, and has been described as crucial in the progression of idiopathic pulmonary fibrosis (IPF). Chronic bird fancier's lung (cBFL) can present a histological pattern of usual interstitial pneumonia (UIP)-like lesions. Little is known about the Th1/Th2 balance in the pathogenesis of cBFL.

Methods: To evaluate the relevance of Th1-type (IP-10) and Th2-type (TARC) chemokines, and their receptors (CXCR3 and CCR4) with reference to histological patterns of cBFL We analyzed 40 patients with cBFL who underwent surgical lung biopsies, 12 acute BFL (aBFL) and 10 healthy volunteers. We measured IP-10 and TARC levels in serum and bronchoalveolar lavage fluid (BALF) by ELISA. Immunohistochemistry for CXCR3 and CCR4 was performed on surgical lung specimens.

Results: The ratio of TARC to IP-10 in serum of patients with UIP-like lesions was significantly higher than that with cNSIP/OP-like lesions, aBFL, and healthy volunteers. The ratio of CCR4 to CXCR3 in UIP-like lesions was significantly higher than that in cNSIP/OP-like lesions and fNSIP-like lesions. The ratio of CCR4- to CXCR3-positive cells correlated with the ratio of TARC to IP-10 in serum.

Conclusions: A Th2 predominant immune response may play an important role in the development of UIP-like lesions as already observed in IPF. A Th1 predominance may play a role in the development of cNSIP/OP-like lesions in cBFL.

Keywords: CCR4, CXCR3, IP-10, TARC, UIP