Inflammation

Smoking, HIV Increases Inflammation in the Lung Cells

Among individuals with HIV, smoking causes inflammation in alveolar macrophages, which leads to increased inflammation in the lungs, according to new research presented at the Conference on Retroviruses and Opportunistic Infections 2019.

Alveolar macrophages play an important role in host defense against pathogenic microorganisms and tissue remodeling. However, studying the effect of HIV on these macrophages prove difficult due to the high prevalence of smoking among the HIV population.

Therefore, Dr Charles P. Neff and colleagues from the University of Colorado investigated the effect of HIV infection and smoking on alveolar macrophages.

To conduct their study, the researchers subjected participants’ bronchoalveolar lavage cells to Cytometry by Time of Flight (CyTOF). Participants included:

  • 10 individuals with HIV who are not on treatment and do not smoke,
  • 9 individuals with HIV who are not on treatment and smoke,
  • 10 individuals who are HIV-seronegative and do not smoke, and
  • 9 individuals who were HIV-seronegative and smoke.


After analyzing the 34 unique markers, the researchers found a decrease in CD206, CD71, and CD164 positive cells in individuals with HIV compared with those without HIV. This indicates a loss of alternatively activated alveolar macrophages caused by HIV; this loss is linked with an increased inflammatory environment, the researchers noted.

In addition, the researchers found that smoking increased alveolar macrophage expression of CCR2—a marker of inflammatory macrophages—and increased expression of CXCR4 on alveolar macrophages compared with healthy nonsmokers.

“While the aim of characterizing alveolar macrophages during HIV infection and smoking was our primary goal, this study also demonstrates the sensitivity of mass cytometry, and its ability to detect significant differences between patient groups which would have otherwise been masked by auto-fluorescence,” the researchers concluded.

“Overall, these findings indicate that HIV and smoking drive alveolar macrophages toward an inflammatory state, leading to an overall more inflammatory environment in the lung.”

—Amanda Balbi

 

Reference:

Neff CP, Campbell T, Fontenot A, Palmer BE. HIV infection and smoking deferentially regulate alveolar macrophages. Paper presented at: Conference on Retroviruses and Opportunistic Infections 2019; March 4-7, 2019; Seattle, WA. http://www.croiconference.org/sessions/hiv-infection-and-smoking-deferentially-regulate-alveolar-macrophages. Accessed March 7, 2019.