Could stem cells help breathe easier in severe COPD?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Adults aged 40 to 75 years. * Diagnosed with Group E Chronic Obstructive Pulmonary Disease (COPD) according to GOLD 2023 criteria. * Receiving triple inhalation therapy (long-acting beta-agonist, inhaled corticosteroid, long-acting muscarinic antagonist) for at least 6 months prior to enrollment. * Clinically stable for at least 2 weeks prior to enrollment. * Provided written informed consent to participate in the study. Exclusion Criteria: * Current smoker or stopped smoking less than 6 months prior to screening. * Acute exacerbation of COPD within 2 weeks prior to enrollment. * Diagnosis of pulmonary diseases other than COPD, including tuberculosis, pulmonary embolism, pneumothorax, multiple bullae, asthma, interstitial lung disease, or lung cancer. * History of tuberculosis within the past 10 years. * Active infection (including HIV positive). * Malignancy of any type. * Severe cardiac disease, including congestive heart failure classified as NYHA class III or IV, significant arrhythmias, valvular heart disease, cardiomyopathy, or congenital heart disease. * Severe hepatic dysfunction (SGOT, SGPT, or bilirubin levels \>2 times upper limit of normal). * Severe renal dysfunction (serum creatinine \>1.5 times upper limit of normal). * Pregnant or breastfeeding. * Comorbid conditions that may affect survival (e.g., advanced diabetes mellitus with HbA1c \>7%, recent myocardial infarction, unstable angina, liver cirrhosis, acute glomerulonephritis). * Leukopenia (white blood cell count \<4×10⁹/L) or agranulocytosis (white blood cell count \<1.5×10⁹/L or neutrophils \<0.5×10⁹/L). * History of psychiatric illness, epilepsy, or other central nervous system disorders. * History of alcohol or drug abuse. * Participation in another clinical trial within 3 months prior to enrollment. * Poor adherence to prior medical care or expected difficulty completing the study protocol. * Inability to perform spirometry maneuvers. * Life expectancy less than 6 months due to comorbid conditions. * Use of immunosuppressive therapy within 8 months prior to screening.