HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Permissions Request Permissions Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Maher, T. M. Articles by Laurent, G. J. Search for Related Content PubMed Articles by Maher, T. M. Articles by Laurent, G. J.

From the authors

¹ Centre for Respiratory Research, Rayne Institute, University College London, and ² Interstitial Lung Disease Unit, Royal Brompton Hospital, London, UK.

We appreciate the comments of H.E. Collard and T.E. King on our article 1. The American Thoracic Society (ATS)/European Respiratory Society (ERS) consensus classification has been important in advancing clinical understanding of the idiopathic interstitial pneumonias 2. In that document, the clinical entity of nonspecific interstitial pneumonia (NSIP) was proposed as a provisional term only. As we have argued, we believe that using histological appearances alone to define separate clinical entities is unhelpful 1. Different histological patterns may occur in the same patient 3. Furthermore, conditions with a defined aetiology (e.g. hypersensitivity pneumonitis, connective tissue disease or familial pulmonary fibrosis) may give rise to either usual interstitial pneumonia (UIP) or NSIP in different patients 4–6.

By associating the histological lesion of NSIP with a clinical diagnosis of NSIP, the ATS/ERS consensus classification has blurred the distinction between idiopathic and secondary NSIP in the minds of many clinicians. This has led some to consider NSIP as a single disorder. We agree strongly with H.E. Collard and T.E. King that many cases of NSIP are due to either connective tissue disease or hypersensitivity pneumonitis. However, when reviewing the clinical data in such cases there are often ancillary features that point to the underlying diagnosis 7. Once secondary cases are excluded, there remains a large sub-group of NSIP patients who have a clinical phenotype that overlaps substantially with that of UIP/idiopathic pulmonary fibrosis (IPF). This group of patients have a sex distribution, smoking-exposure history, mode of clinical presentation, distribution of clinical signs and bronchoalveolar lavage cell differential that mirrors that of IPF/UIP 2, 8, 9. The distribution of disease on high-resolution computed tomography is also strikingly similar 10.

We therefore propose that idiopathic UIP and idiopathic NSIP, sharing a common clinical phenotype, form a spectrum of disease with a common pathogenesis. The pathogenetic mechanisms involved in the development and progression of IPF are complex and are likely to involve abnormalities in a number of the multiple pathways of normal wound healing 1. It seems likely that the balance of abnormalities in each of the key wound-healing pathways may vary between individuals. This variation is likely to be responsible for the range of clinical, radiological and pathological phenotypes observed in IPF.

Like H.E. Collard and T.E. King, we hope that future clinical and scientific research will further clarify these issues, as advances in our understanding of idiopathic pulmonary fibrosis can only be to the benefit of patients with this devastating and currently untreatable disease.

Statement of interest

None declared.

REFERENCES

1. Maher TM, Wells AU, Laurent GJ. Idiopathic pulmonary fibrosis: multiple causes and multiple mechanisms?. Eur Respir J 2007;30:835–839.[Abstract/Free Full Text]
2. American Thoracic Society, European Respiratory Society. American Thoracic Society/European Respiratory Society International Multidisciplinary Consensus Classification of the Idiopathic Interstitial Pneumonias. Am J Respir Crit Care Med 2002;165:277–304.[Free Full Text]
3. Monaghan H, Wells AU, Colby TV, du Bois RM, Hansell DM, Nicholson AG. Prognostic implications of histologic patterns in multiple surgical lung biopsies from patients with idiopathic interstitial pneumonias. Chest 2004;125:522–526.[CrossRef][Web of Science][Medline] [Order article via Infotrieve]
4. Ohtani Y, Saiki S, Kitaichi M, et al. Chronic bird fancier's lung: histopathological and clinical correlation. An application of the 2002 ATS/ERS consensus classification of the idiopathic interstitial pneumonias. Thorax 2005;60:665–671.[Abstract/Free Full Text]
5. Rosas IO, Ren P, Avila NA, et al. Early interstitial lung disease in familial pulmonary fibrosis. Am J Respir Crit Care Med 2007;176:698–705.[Abstract/Free Full Text]
6. Park JH, Kim DS, Park IN, et al. Prognosis of fibrotic interstitial pneumonia: idiopathic versus collagen vascular disease-related subtypes. Am J Respir Crit Care Med 2007;175:705–711.[Abstract/Free Full Text]
7. Kinder BW, Collard HR, Koth L, et al. Idiopathic nonspecific interstitial pneumonia: lung manifestation of undifferentiated connective tissue disease?. Am J Respir Crit Care Med 2007;176:691–697.[Abstract/Free Full Text]
8. Bjoraker JA, Ryu JH, Edwin MK, et al. Prognostic significance of histopathologic subsets in idiopathic pulmonary fibrosis. Am J Respir Crit Care Med 1998;157:199–203.[Web of Science][Medline] [Order article via Infotrieve]
9. Veeraraghavan S, Latsi PI, Wells AU, et al. BAL findings in idiopathic nonspecific interstitial pneumonia and usual interstitial pneumonia. Eur Respir J 2003;22:239–244.[Abstract/Free Full Text]
10. MacDonald SL, Rubens MB, Hansell DM, et al. Nonspecific interstitial pneumonia and usual interstitial pneumonia: comparative appearances at and diagnostic accuracy of thin-section CT. Radiology 2001;221:600–605.[Abstract/Free Full Text]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Permissions Request Permissions Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Maher, T. M. Articles by Laurent, G. J. Search for Related Content PubMed Articles by Maher, T. M. Articles by Laurent, G. J.