If you want to breathe easily, it’s important that your alveoli—the tiny air sacs within your lungs—remain springy and elastic, so they can efficiently exchange carbon dioxide for oxygen. Sometimes, however, alveoli become scarred and collapse (picture the texture of a dried-up sponge). This makes the exchange of gases during respiration, and the act itself of breathing, more difficult.
Interstitial lung disease (ILD) is actually a group of disorders where such scarring, or fibrosis, of lung tissue occurs and is progressive. There are many causes of ILD, including: occupational or environmental exposure to irritants like asbestos and silica, radiation therapy, some types of chemotherapy drugs, and connective tissue diseases like lupus and rheumatoid arthritis.
The biggest misconception about ILD is that it’s rare. In fact, while most people are unfamiliar with the term “ILD,” many probably know someone who is suffering from one of ILD’s many forms or who has died from the disease. According to doctors, there might be 100 or more types of ILD, although only about half are generally seen in the clinic. Most forms are still poorly understood, unsolved medical puzzles.
The best explanation for ILD that we have so far is that repeated injury to the lungs leads to abnormal repair of the alveoli. In other words, although the human body normally generates just the right amount of tissue to repair damage, an excessive amount is made in the case of ILD.
Despite its prevalence, the cause of idiopathic pulmonary fibrosis (IPF) is still unknown (hence the term “idiopathic”). More than half of the people with this form of ILD will die within three years of diagnosis, while others exhibit milder symptoms and survive much longer. Researchers believe that genetic factors are at play in individual patients.
In fact, studies indicate that nearly 20 percent of sufferers may have a genetic predisposition to IPF. So far, two sets of genes have been identified as likely culprits associated with IPF: rare mutations in genes coding for two proteins that normally help keep alveoli from collapsing upon themselves, and mutations in telomerase genes, which help protect the ends of our chromosomes.
The LGRC is using sophisticated genomic technologies to examine ILD at the molecular level. By carefully analyzing genes and their expression profiles in affected individuals, we hope to discover unique types of ILD and better define their key characteristics. We also want to determine whether certain mutations that occur in the lungs are placing individuals at risk of developing IPF.
As we learn more about ILD, we may be able to use genetic data together with information such as age, dust exposure levels, and other factors to predict a person’s susceptibility to ILD or to select the best treatment for a patient. Moving forward, our goal is to also develop new, more effective therapies that will improve the length and quality of life for those faced with this challenging disease.
For more information, visit the National Jewish Health’s page on ILD.