Desquamative interstitial pneumonitis. Cellular phase of fibrosing alveolitis

Our plain-English summary of Desquamative interstitial pneumonitis. Cellular phase of fibrosing alveolitis, by R.R. Tubbs, S.P. Benjamin, N.E. Reich, et al (Chest, 1977).

The study

• Authors: R.R. Tubbs, S.P. Benjamin, N.E. Reich, L.J. McCormack, H.S. Van Ordstrand
• Journal: Chest
• Published: 1977;72(2):159-65
• Cited by: 52 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Since the original description of desquamative interstitial pneumonitis in 1967, several investigators have questioned the specificity of the disease. The concept of desquamative interstitial pneumonitis and usual fibrosing interstitial pneumonitis as two manifestations of a nonspecific disease spectrum has been proposed. Twenty-six patients with desquamative interstitial pneumonitis were evaluated with respect to clinicopathologic correlates. Biopsies were reviewed without knowledge of the patients' clinical course. The absolute histopathologic criteria for the diagnosis were (1) intra-alveolar accumulations of free alveolar cells with PAS-positive diastaseresistant cytoplasmic granules; (2) mononuclear cell interstitial inflammation; and (3) absence of necrosis, hyaline membranes, intra-alveolar fibrosis, asbestos bodies, and birefringent crystalline dust material. Transmission electron microscopic studies revealed the dominant alveolar lining cell to be the granular pneumocyte, with a prominent population of free alveolar macrophages. Patients were segregated into group 1 (cellular phase) and 2 (cicatrized phase). Although favorable short-term responses to corticosteroid therapy were observed in both groups, long-term responses were variable. Apparent complete remissions were noted in both groups.

In plain English

This article described 26 patients with desquamative interstitial pneumonitis, a form of lung inflammation and scarring, seen at the Cleveland Clinic from January 1969 through April 1976. It was not a study of asbestos exposure. Instead, finding no asbestos bodies or birefringent crystalline dust material in the lung biopsy was one of the required criteria for the diagnosis. Biopsies were graded without knowledge of each patient's clinical course. Most specimens showed minimal or no fibrosis; six showed moderate and six showed severe fibrosis. Patients with mild or no fibrosis had had symptoms for an average of 16 months before biopsy, compared with 44 months for those with moderate to severe fibrosis (P less than 0.025). Most steroid-treated patients improved in the short term, but the disease often progressed later. Three apparent complete remissions occurred, one in a patient with severe fibrosis. Five of the 26 patients had died. The authors concluded that their findings support the idea that desquamative interstitial pneumonitis can progress to usual fibrosing interstitial pneumonitis. They noted that a single biopsy may not show how much of the whole lung is involved.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Clinicopathologic case series using light and electron microscopy, with biopsies reviewed without knowledge of the clinical course
• Who was studied: 26 patients with desquamative interstitial pneumonitis examined in the Department of Pulmonary Medicine at the Cleveland Clinic, January 1969 through April 1976. There were 17 men and nine women, aged 24 to 75 (median 52). Fifteen of the 26 had smoked more than ten pack-years.
• Exposure: No asbestos or other occupational exposure was studied. The absence of asbestos bodies and of birefringent crystalline dust material in the biopsy was a required diagnostic criterion. Twenty patients received corticosteroids.
• Main results:
  • Most of the 26 specimens showed minimal or no interstitial fibrosis. Six showed moderate fibrosis and six showed severe fibrosis.
  • Mean duration of symptoms before biopsy was 16 months in patients with mild or no fibrosis and 44 months in patients with moderate to severe fibrosis, a difference the authors called significant (P less than 0.025).
  • Sixteen patients had a decreased vital capacity (mean 71 percent of predicted). Arterial oxygen pressure was consistently reduced (mean 64 mm Hg, range 50 to 80 mm Hg).
  • No consistent correlation was found between degree of fibrosis and treatment results. Three apparent complete remissions occurred, one in a patient with severe fibrosis (case 11).
  • Most steroid-treated patients had a favorable short-term response, regardless of degree of fibrosis. Over the long term, progression frequently occurred despite treatment.
  • Five of the 26 patients had died, three from severe respiratory insufficiency. No postmortem examinations were performed.
  • Electron microscopy of tissue from five patients showed that granular pneumocytes made up most of the alveolar lining cells and macrophages were the main cells within the air spaces. No viral particles were seen.
• The authors' conclusion: The authors concluded that the shorter symptom duration in patients with mild or no fibrosis, and the longer duration in those with advanced fibrosis, support the concept of transition from desquamative interstitial pneumonitis to usual fibrosing interstitial pneumonitis.
• Limitations the authors state:
  • The process was multifocal in nine specimens. A single biopsy specimen cannot show the degree of total lung involvement, so comparisons of histology with clinical findings must be tempered.

Topics

Medical terms in this study, explained in our Lexicon: Interstitial, Pneumonitis, Inflammation, Necrosis, Fibrosis, Asbestos Bodies, Crystalline, Alveolar Macrophage.

Related studies

• British Thoracic Society study of cryptogenic fibrosing alveolitis: current presentation and initial management. Fibrosing Alveolitis Subcommittee of the Research Committee of the British Thoracic Society — I.D. Johnston, R.J. Prescott, et al. (1997)
• Fine structural changes in cryptogenic fibrosing alveolitis and asbestosis — B. Corrin, A. Dewar, et al. (1985)
• Electron microscopic studies in desquamative interstitial pneumonia associated with asbestos — B. Corrin, A.B. Price (1972)
• Desquamative interstitial pneumonia associated with chrysotile asbestos fibres — J.A. Freed, A. Miller, et al. (1991)
• Possible value of antifibrotic drugs in patients with progressive fibrosing non-IPF interstitial lung diseases — S.E. Torrisi, N. Kahn, et al. (2019)
• Characterization of the bronchoalveolar cellular response in experimental asbestosis. Different reactions depending on the fibrogenic potential — I. Lemaire (1985)

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