Smokers with HIV are significantly more likely to develop the lung condition emphysema than HIV-negative smokers. Emphysema is a condition in which lung tissue is destroyed, possibly by immune system reactions, and researchers from Ohio State University in the United States have discovered that the development of emphysema is vastly accelerated in HIV-positive people.
Researchers recruited 114 HIV-positive patients and 44 HIV-negative individuals matched for age, sex and smoking history. They found that 15% of HIV-positive patients had emphysema, compared with 2% of the HIV-negative group, and in people who had smoked for 12 years or more, the difference was even more striking. 37% of the long-term HIV-positive smokers had evidence of emphysema, whilst none of the long-term HIV-negative smokers had signs of emphysema. The average age of the HIV-positive patients was 34, indicating very early onset of smoking-related emphysema.
HIV-positive smokers were also found to have much higher levels of cytotoxic lymphocytes (CD8+ cells) in their lung tissue, and the researchers suggest that some of the damage may have been caused by these immune cells. This study was conducted between 1994 and 1997, before the widespread use of protease inhibitor therapy amongst these patients, and HAART is known to reduce levels of CD8+ cells. But if this form of immune activation is not responsible for accelerated emphysema, the researchers warn that the condition could become a more common problem as people with HIV live longer.
Reference
Diaz P et al. Increased susceptibility to pulmonary emphysema among HIV-seropositive smokers. Annals of Internal Medicine 132: 369-372, 2000.