This study is exploring a new treatment for people with **moderate-to-severe asthma**, which is a breathing problem that doesn't go away easily even with medication. The treatment uses special cells called **Mesenchymal Stem Cells (MSCs)** that come from bone marrow and help reduce inflammation and repair tissues. There are two types of these cells being tested: **cMSCs** from cord tissue and **γMSCs** that are specially prepared. The study aims to check if these treatments are safe for patients. **Key Points**: - The study lasts 1 year and involves up to 12 visits. - Participants will receive a single infusion of cells and are compensated for their time. - The study is conducted in Children's Healthcare of Atlanta and Emory University. To be part of the study, you must be 18 to 30 years old, have had asthma since childhood, and meet other specific health criteria. Some people may not get direct benefits from the study, but it can help improve asthma care in the future. If you join, you will need to avoid other new asthma treatments during the study.