Cell Therapy in Multiple Sclerosis: Clinical Advances, Limitations, and Future Perspectives from Clinical Studies—A Systematic Review. - Mohamed Fathy Kamal, Ola; Ojeda-Hernández, Doddy Denise; Selma-Calvo, Belén; García-Martín, Marina; Larriba-González, María Teresa; Martin-Blanco, Lucia; Matias-Guiu, Jordi A.; Matias-Guiu, Jorge; Gomez-Pinedo, Ulises (Pharmaceutics, 2026)