HSP47 in lung fibroblasts is a predictor of survival in fibrotic nonspecific interstitial pneumonia.

BACKGROUND: The histopathologic pattern is currently the most important prognostic marker for idiopathic interstitial pneumonia (IIP). However, more highly sensitive markers are now required. Heat shock protein (HSP) 47, a collagen-specific molecular chaperone, is involved in the processing and/or secretion of procollagens, and it has been demonstrated that HSP47 expression is significantly higher in the lung specimens of idiopathic UIP than in UIP associated with collagen vascular diseases (CVD). However, its expression in nonspecific interstitial pneumonia (NSIP), the other common pathological pattern of IIP, has not been well investigated. Therefore, the association between lung fibroblast HSP47 expression and prognosis in fibrotic NSIP was evaluated.

METHODS: Surgical lung biopsy specimens of 63 patients [idiopathic fibrotic NSIP=19, fibrotic NSIP associated with CVD=9, idiopathic UIP=26, and UIP associated with CVD=9] were reviewed, and a score for lung fibroblast HSP47 expression was assigned. These patients' clinical features and survival were also analyzed.

RESULTS: There was no significant difference in HSP47 expression between idiopathic fibrotic NSIP and fibrotic NSIP associated with CVD. The idiopathic fibrotic NSIP patients with higher HSP47 expression levels in their lung specimens had a poorer prognosis than patients with lower HSP47 expression levels.

CONCLUSIONS: The present results suggest that lung fibroblast HSP47 expression may be a useful new prognostic marker for idiopathic fibrotic nonspecific interstitial pneumonia.