Expression of IL-15 in inflammatory pulmonary diseases

J Allergy Clin Immunol. 2001 Dec;108(6):970-5. doi: 10.1067/mai.2001.119556.


Background: IL-15 is a T(H)1-related cytokine that shares many biologic activities with IL-2. Both cytokines bind a specific alpha subunit, and they share the same beta and gamma common receptor subunits for signal transduction. IL-15 has recently been shown to be upregulated in T cell-mediated inflammatory disorders, such as rheumatoid arthritis and inflammatory bowel diseases. However, the role and expression of IL-15 in inflammatory lung disease has not been investigated.

Objective: In the present study we have evaluated the expression of IL-15 mRNA and protein in bronchial biopsy specimens obtained from patients with sarcoidosis (n = 8), tuberculosis (n = 7), chronic bronchitis (n = 10), and bronchial asthma (n = 8) and compared its expression with that seen in normal control subjects (n = 11).

Methods: In situ hybridization and immunocytochemistry were used to detect the number of cells expressing IL-15 mRNA and protein, respectively, within sections of bronchial tissues from all subject groups. In addition, double immunocytochemistry was used to characterize the cellular source of IL-15.

Results: The number of IL-15(+) cells was significantly higher within tissue from patients with sarcoidosis, tuberculosis, and chronic bronchitis compared with that in asthmatic patients and normal control subjects. Similar results were obtained for IL-15 immunoreactivity by using immunohistochemistry. Furthermore, double immunostaining revealed that neutrophils and macrophages are the major source of IL-15.

Conclusion: These results suggest that the expression of IL-15 may be associated with T(H)1-mediated chronic inflammatory diseases of the lung.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Asthma / immunology*
  • Bronchitis / immunology*
  • Humans
  • Immunohistochemistry
  • Interleukin-15 / analysis*
  • Interleukin-15 / genetics
  • Interleukin-15 / physiology
  • Interleukin-8 / physiology
  • Neutrophils / physiology
  • RNA, Messenger / analysis
  • Sarcoidosis / immunology*
  • Th1 Cells / physiology
  • Tuberculosis, Pulmonary / immunology*


  • Interleukin-15
  • Interleukin-8
  • RNA, Messenger