Role of Pneumocystis in COPD Progression
Initial Award Abstract
Chronic obstructive pulmonary disease (COPD) is a lung disease caused by smoking. COPD is also often referred to as emphysema. Patients with COPD may experience difficulty breathing, chronic cough, weight loss, and periods of worsening that require hospitalization. Approximately 2.7 million people died from COPD worldwide in 2000, and it is the fourth leading cause of death in the United States. Although smoking cessation can help slow the progression of the disease, we currently have no effective treatments for COPD.
Despite the fact that smoking is the primary risk for COPD, not all smokers develop the disease. The observation that some smokers are more vulnerable to developing COPD suggests that other factors are important in determining who develops COPD. One factor that might be important in disease progression is the presence of low-level infections in the lungs. These low-level infections often do not cause any symptoms and are also known as colonization. Smoking damages the lung and makes patients more susceptible to colonization. Once colonization is established, it triggers inflammation in the lungs that, although intended to fight the infection, can actually destroy healthy lung tissue. The inflammation and tissue damage resulting both from smoking and from colonization may ultimately result in COPD.
We propose to look at the role of colonization with Pneumocystis carinii in the development of COPD in smokers. Pneumocystis is a fungus that causes pneumonia in patients with HIV infection or weakened immune systems. By using sensitive molecular techniques, we have discovered that patients with COPD are colonized with Pneumocystis more often than patients with other lung diseases and more often than smokers who do not have COPD. Because the body reacts to Pneumocystis with inflammation that is similar to that seen in patients with COPD, we believe that it may be one factor that causes smokers to develop COPD. To test the role of Pneumocystis in COPD, we will study a group of smokers and test their sputum for Pneumocystis. We will then determine if patients who are colonized with Pneumocystis have more severe COPD and if their COPD worsens more quickly than those who are not colonized. In order to understand if Pneumocystis is causing damage from inflammation in the lungs, we will examine sputum in colonized patients to determine if they have more inflammation than non-colonized patients. We will test to see if the degree of inflammation associated with Pneumocystis is related to the degree of COPD in the patients.
This study will help us understand how COPD develops. By determining the role of this infection in COPD, we will be able identify a factor that might help us recognize people at higher risk of COPD. Because infection with Pneumocystis is treatable with antibiotics, we might be able to offer an effective therapy that could potentially prevent or slow the progression of COPD. |