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


CONCLUSIONS
We found high levels of anti-HSP47 autoantibody titers in sera of patients with idiopathic fibrosing NSIP compared with other IIPs and healthy volunteers.
Kakugawa
Tomoyuki
T
Second Department of Internal Medicine, Nagasaki University School of Medicine, Nagasaki, Japan. tomoyukikakugawa@yahoo.co.jp
Yokota
Shin-ichi
S
Mukae
Hiroshi
H
Kubota
Hiroshi
H
Sakamoto
Noriho
N
Mizunoe
Syunji
S
Matsuoka
Yasuhiro
Y
Kadota
Jun-ichi
J
Fujii
Nobuhiro
N
Nagata
Kazuhiro
K
Kohno
Shigeru
S
D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D003937:Diagnosis, Differential; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D050958:HSP47 Heat-Shock Proteins / Q000276:immunology*; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000175:diagnosis / Q000276:immunology*; D017563:Lung Diseases, Interstitial / Q000175:diagnosis / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
D001323:Autoantibodies; D015415:Biomarkers; D050958:HSP47 Heat-Shock Proteins