Two stem cell experts have found an abundance of abnormal stem cells in the lungs of patients who suffer from Chronic Obstructive Pulmonary Disease (COPD), a leading cause of death worldwide. "We actually found that three variant cells in all COPD patients drive all the key features of the disease. One produces tremendous amounts of mucins which block the small airways, while the other two drive fibrosis and inflammation which together degrade the function of the lung," Xian reports in the May 14 issue of the journal Cell. "These patients have normal stem cells, though not many of them, but...