Effects of nitrogen dioxide exposure on human host defense

Mitra Azadniv, Mark J. Utell, Paul E. Morrow, F. Raymond Gibb, Joan Nichols, Norbert J. Roberts, Donna M. Speers, Alfonso Torres, Ying Tsai, Michael K. Abraham, Karen Z. Voter, Mark W. Frampton

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Nitrogen dioxide (NO2) exposure has been linked with increased respiratory illness and infection. The objective of this study was to determine whether exposure at peak indoor levels causes airway inflammation or impairs local or systemic host defense in humans either immediately or 18 h after exposure. In an initial phase, 12 volunteers were exposed to purified air or a targeted concentration of 2.0 ppm NO2 for 6 h, with intermittent exercise, and underwent bronchoalveolar lavage (BAL) 18 h after exposure. In a second phase, 12 volunteers participated in an identical exposure protocol but BAL was performed immediately after exposure. Eighteen hours after exposure to NO2, polymorphonuclear leukocytes recovered by BAL increased from 2.2 ± 0.3 to 3.1 ± 0.4% (p = .005) and small decreases were found in the percentage of blood CD8+ T lymphocytes (p = .01) and in blood T lymphocytes expressing neither CD4 nor CD8 (p = .03). These variables were not significantly different immediately after NO2 exposure. Nitrogen dioxide exposure did not alter lymphocyte subsets in BAL or alveolar macrophage function at either time point. Exposure to 2.0 ppm NO2 for 6 h with exercise causes airway inflammation and may alter blood lymphocyte populations 18 h after exposure.

Original languageEnglish (US)
Pages (from-to)585-601
Number of pages17
JournalInhalation Toxicology
Issue number6
StatePublished - Jun 1998

ASJC Scopus subject areas

  • Toxicology
  • Health, Toxicology and Mutagenesis


Dive into the research topics of 'Effects of nitrogen dioxide exposure on human host defense'. Together they form a unique fingerprint.

Cite this