Alpha-1 antitrypsin is an anti-inflammatory protein that protects the tissue of the body. One of its most important roles is to shield the delicate tissues of the lungs by binding to neutrophil elastase, an enzyme released by certain white blood cells that digests bacteria and other foreign substances in the lungs. When a person with deficient levels of AAT inhales irritants or contracts a lung infection, the neutrophil elastase released to protect the lungs is uncontrolled and can injure healthy lung tissue. Repeated injury to the normal structure of the lungs can eventually result in emphysema, a condition affecting 54 percent of diagnosed AAT deficient patients, according to a recent registry. Identifying patients with AAT deficiency can be problematic.... Because AAT deficiency typically involves such common symptoms as shortness of breath on exertion, wheezing, and coughing, the condition is often misdiagnosed as another chronic lung condition.