Pulmonary blue bodies

Our plain-English summary of Pulmonary blue bodies, by M.N. Koss, F.B. Johnson, L. Hochholzer (Human Pathology, 1981).

The study

• Authors: M.N. Koss, F.B. Johnson, L. Hochholzer
• Journal: Human Pathology
• Published: 1981;12(3):258-66
• Cited by: 20 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Pulmonary blue bodies are intra-alveolar laminated basophilic concretions of uncertain etiology. Blue bodies were studied in lung biopsy specimens from 10 patients. The patients ranged in age from 47 to 69 years and were predominantly men. Three had a history of overt exposure to environmental dusts such as sawdust and asbestos, and two showed occasional ferruginous bodies in the lung, raising the possibility of pneumoconiosis. In eight cases there was interstitial pneumonitis, which resembled desquamative interstitial pneumonia by light microscopy but which was often seen to be patchy and asymmetrically distributed in the lung by chest x-ray examination. Of two other patients, one had xanthogranulomatous inflammation and the other, necrotizing granulomatous inflammation. Light and electron microscopic, histochemical, microchemical, and x-ray diffraction studies of blue bodies were also performed. Calcium carbonate is a major component of blue bodies and is responsible for their birefringence in unstained sections and ready solubility in acid solutions. Blue bodies also contain a mucopolysaccharide matrix and iron. We offer the hypothesis that blue bodies (calcium carbonate) are a product of histiocytic catabolism.

In plain English

This was a pathology study of 10 patients whose lung tissue contained "blue bodies": small, layered, blue-staining deposits inside the lung's air sacs, whose cause was uncertain. The cases came from the files of the Armed Forces Institute of Pathology. The patients were 47 to 69 years old; eight were men and two were women. Occupational histories were available for six. Three of them had overt exposure to environmental dusts, including sawdust, asbestos, or coal and rock dusts, and two others were potentially exposed. Eight patients had an interstitial pneumonitis resembling desquamative interstitial pneumonia. Of the other two, one had xanthogranulomatous inflammation and one had necrotizing granulomatous inflammation. Two patients had a few ferruginous bodies in the lung, and one of these also had a pleural plaque. Laboratory tests showed that calcium carbonate, in the form of calcite, was a major component of the blue bodies, along with a mucopolysaccharide matrix and iron. The authors proposed that blue bodies are a product of histiocytic catabolism, meaning the breakdown activity of scavenger cells. They noted that a few ferruginous bodies can occur in the lungs of normal city dwellers, so these might be unrelated to the disease. They also said the role of inhaled dusts remained to be explored.

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: case series (pathology study) using light and electron microscopy, histochemical, microchemical and x-ray diffraction analyses
• Who was studied: 10 patients with pulmonary blue bodies, from the files of the Armed Forces Institute of Pathology (Washington, D.C.); aged 47 to 69 years, eight men and two women; years of the cases not stated
• Exposure: Occupational histories were available for six patients. Three had overt exposure to environmental dusts including sawdust, asbestos, or coal and rock dusts. Two others were potentially exposed through working near dust sources (a warehouse storing electrical equipment and a car body shop). No fiber types were specified.
• Main results:
  • Eight patients had pneumonitis resembling desquamative interstitial pneumonia.
  • The other two patients had xanthogranulomatous inflammation (one) and necrotizing granulomatous inflammation (one).
  • Two patients showed occasional ferruginous bodies in the lung, which the authors said raised the possibility of pneumoconiosis.
  • One of the two patients with ferruginous bodies also had a pleural plaque.
  • One additional patient had Kuhn's hyalin (cell inclusions associated in some cases with asbestos exposure) in alveolar epithelial cells, but no ferruginous bodies were seen by light microscopy in that case.
  • Small numbers of silica-like particles and anthracotic pigment were seen in all eight pneumonitis cases, but no more than in the lungs of normal city dwellers.
  • Calcium carbonate (calcite on x-ray diffraction) was a major component of the blue bodies.
  • Blue bodies also contained a mucopolysaccharide matrix and iron.
• The authors' conclusion: The authors offered the hypothesis that blue bodies (calcium carbonate) are a product of histiocytic catabolism. They said the role of other factors, such as inhaled dusts, remains to be explored.
• Limitations the authors state:
  • Complete clinical data were not available in all cases.
  • Chest x-ray pictures were available in only two cases; the rest had reports only.
  • A few ferruginous bodies may be seen in otherwise normal lungs of city dwellers, so their presence may be unrelated to the pneumonitis.
  • Sampling problems might account for the apparent absence of ferruginous bodies in the other cases.
  • It was unclear whether symptom stabilization reflected corticosteroid treatment or remission of the disease.
  • The proposed theory does not explain why blue bodies are rare in some other diseases with similar features.
  • The role of inhaled dusts in forming blue bodies was not established.

Topics

Medical terms in this study, explained in our Lexicon: Etiology, Biopsy, Ferruginous Bodies, Pneumoconiosis, Interstitial, Pneumonitis, Chest X-Ray, Inflammation.

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