Research article

High serum concentrations of autoantibodies to HSP47 in nonspecific interstitial pneumonia compared with idiopathic pulmonary fibrosis

Tomoyuki Kakugawa¹ , Shin-ichi Yokota² , Hiroshi Mukae¹ , Hiroshi Kubota⁴ , Noriho Sakamoto¹ , Syunji Mizunoe³ , Yasuhiro Matsuoka⁴ , Jun-ichi Kadota³ , Nobuhiro Fujii² , Kazuhiro Nagata⁴ and Shigeru Kohno¹

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

²  Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan

³  Division of Pathogenesis and Disease Control, Department of Infectious Diseases, Oita University Faculty of Medicine, Oita, Japan

⁴  Department of Molecular and Cellular Biology and CREST/JST, Institute for Frontier Medical Sciences, Kyoto University, Japan

author email corresponding author email

BMC Pulmonary Medicine 2008, 8:23doi:10.1186/1471-2466-8-23

Published:	4 November 2008

Abstract

Background

The pathological diagnosis of idiopathic interstitial pneumonias (IIP) by surgical lung biopsy is important for clinical decision-making. However, there is a need to use less invasive biomarkers to differentiate nonspecific interstitial pneumonia (NSIP) from other IIP such as usual interstitial pneumonia (UIP). Heat shock protein (HSP) 47, a collagen-specific molecular chaperone, is involved in the processing and/or secretion of procollagen. HSP47 is increased in various fibrotic diseases. We investigated the autoantibodies to HSP47 in IIPs.

Methods

We measured the serum levels of the autoantibodies to HSP47 in 38 patients with various forms of IIP [16 with idiopathic pulmonary fibrosis (IPF), 15 with idiopathic NSIP, 7 with cryptogenic organizing pneumonia (COP)] and 18 healthy volunteers.

Results

The serum levels of autoantibodies to HSP47 in patients with idiopathic NSIP were significantly higher than in patients with IPF (P < 0.01), COP (P < 0.05), and healthy volunteers (P < 0.05). In addition, those in fibrosing NSIP were significantly higher than those of cellular and fibrosing NSIP (p < 0.05).

Conclusion

We found high levels of anti-HSP47 autoantibody titers in sera of patients with idiopathic fibrosing NSIP compared with other IIPs and healthy volunteers.