Long‐term efficacy and safety of intravenous injection of clonal mesenchymal stem cells derived from bone marrow in five adults with moderate to severe atopic dermatitis

Abstract Atopic dermatitis is a chronic and relapsing inflammatory skin disease that is treated with immunosuppressants. However, long‐term use of immunosuppressants may cause toxicity and severe side‐effects. To confirm the long‐term efficacy and safety of clonal mesenchymal stem cell therapy, we performed investigator‐initiated clinical trials and long‐term observation in five adult patients with moderate to severe atopic dermatitis that was refractory to conventional treatments. The clinical response assessment values such as Eczema Area and Severity Index (EASI) improved significantly at 16 weeks, and 80% (4/5) of the patients achieved EASI‐50 after one or two treatment cycles. Patients were observed for long‐term efficacy and safety for an average of 38 weeks (range, 16–86) and showed no serious side‐effects. Among the cytokines tested, CCL‐17, interleukin (IL)‐13, and IL‐22 significantly decreased at the end‐point of the five participants, two patients who maintained good clinical response over 84 weeks showed increased IL‐17 cytokine levels in the blood.