Research

Expression of HSP47 in Usual Interstitial Pneumonia and Nonspecific Interstitial Pneumonia

Tomoyuki Kakugawa¹ , Hiroshi Mukae¹ , Tomayoshi Hayashi² , Hiroshi Ishii¹ , Seiko Nakayama¹ , Noriho Sakamoto¹ , Sumako Yoshioka¹ , Kanako Sugiyama¹ , Mariko Mine³ , Yohei Mizuta¹ and Shigeru Kohno¹

¹Second Department of Internal Medicine, Nagasaki University School of Medicine, Nagasaki, Japan

²Department of Pathology, Nagasaki University Hospital, Nagasaki, Japan

³Biostatistics Section, Division of Scientific Data Registry, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki; Japan

author email corresponding author email

Respiratory Research 2005, 6:57doi:10.1186/1465-9921-6-57

Published:	14 June 2005

Abstract

Background

Heat shock protein (HSP) 47, a collagen-specific molecular chaperone, is involved in the processing and/or secretion of procollagens, and its expression is increased in various fibrotic diseases. The aim of this study was to determine whether quantitative immunohistochemical evaluation of the expression levels of HSP47, type I procollagen and α-smooth muscle actin (SMA) allows the differentiation of idiopathic usual interstitial pneumonia (UIP) from UIP associated with collagen vascular disease (CVD) and idiopathic nonspecific interstitial pneumonia (NSIP).

Methods

We reviewed surgical lung biopsy specimens of 19 patients with idiopathic UIP, 7 with CVD-associated UIP and 16 with idiopathic NSIP and assigned a score for the expression of HSP47, type I procollagen and α-SMA in type II pneumocytes and/or lung fibroblasts (score 0 = no; 1 = weak; 2 = moderate; 3 = strong staining).

Results

The expression level of HSP47 in type II pneumocytes of idiopathic UIP was significantly higher than in CVD-associated UIP and idiopathic NSIP. The expression of HSP47 in fibroblasts was significantly higher in idiopathic UIP and idiopathic NSIP than in CVD-associated UIP. The expression of type I procollagen in type II pneumocytes was significantly higher in idiopathic UIP than in idiopathic NSIP. The expression of type I procollagen in fibroblasts was not different in the three groups, while the expression of α-SMA in fibroblasts was significantly higher in idiopathic UIP than in idiopathic NSIP.

Conclusion

Our results suggest the existence of different fibrotic pathways among these groups involved in the expression of HSP47 and type I procollagen.