UMMS Affiliation

Department of Medicine; Center for Infectious Disease and Vaccine Research; Department of Pathology

Publication Date

5-15-2008

Document Type

Article

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

ABSTRACT: INTRODUCTION: Mycobacterium avium complex (MAC) is an increasingly recognized cause of pulmonary disease in immunocompetent individuals. An acute form of MAC lung disease, MAC-associated pneumonitis, has generally been associated with the use of hot tubs. There is controversy in the literature about whether MAC-associated pneumonitis is a classic hypersensitivity pneumonitis or is a direct manifestation of mycobacterial infection. CASE PRESENTATION: We report the second case in the literature of MAC-associated pneumonitis not related to the use of hot tubs. The source of MAC in a 52-year-old immunocompetent patient was an intrapulmonary cyst containing numerous acid-fast bacilli. The patient developed disseminated miliary nodules throughout both lung fields. Histological examination of resected lung tissue revealed well-formed, acid-fast negative granulomas composed predominantly of CD4+ T-cells and CD68+ histiocytes. The granulomas were strongly positive for tumor necrosis factor-alpha, a pro-inflammatory cytokine. CONCLUSION: The attempt to classify MAC-associated pneumonitis as either a classic hypersensitivity pneumonitis or a direct manifestation of mycobacterial infection is not particularly useful. Our case demonstrates that MAC-associated pneumonitis is characterized by a vigorous T-helper 1-like, pro-inflammatory, immune response to pulmonary mycobacterial infection. The immunopathology provides a rationale for clinical studies of anti-MAC therapy with the addition of anti-inflammatory agents (for example, corticosteroids) to hasten the resolution of infection and symptoms.

Rights and Permissions

Citation: J Med Case Reports. 2008 May 13;2:152. Link to article on publisher's site

DOI of Published Version

10.1186/1752-1947-2-152

Related Resources

Link to Article in PubMed

Journal/Book/Conference Title

Journal of medical case reports

PubMed ID

18477401

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