The suitability of mesenchymal stem cells for treating immune-mediated inflammatory skin diseases: a systematic review.

Mesenchymal stem cell (MSC) therapy holds promise for treating immune-mediated inflammatory skin diseases (IMIDs), particularly when conventional therapies are ineffective. Encouraged by their immunomodulatory capabilities and potential for disease modification, different clinical trials are investigating the efficacy and safety of MSCs in single IMIDs. This review aims to summarize the application of MSCs in IMIDs and explore their future clinical potential. We reviewed published studies from January 2016 to January 2024 on MSC treatment for IMIDs. We retrieved 18 clinical trials and 5 observational studies, encompassing 609 patients with psoriasis, atopic dermatitis (AD), chronic spontaneous urticaria (CSU), alopecia areata (AA), systemic sclerosis (SSc), and systemic lupus erythematosus (SLE). Improvements or complete remission were observed in up to 100% of cases for AA, SSc, and SLE, though complete remission rates were less frequent than improvement rates, ranging from 0% in AD to 50% in CSU. Adverse events (AEs) were generally mild; moderate-severe AEs were uncommon (4% in psoriasis, 2.6% in SLE, and 0.7% in SSc), and deaths from all causes were rare (6 patients with SSc and 15 patients with SLE). In conclusion, MSC therapy shows promising results in terms of at least partial clinical improvement for most IMIDs. Its effect is achievable after a single or a few administrations, with no significant toxicity. MSCs may fulfill an unmet need for patients unresponsive to conventional immunomodulating agents. However, most evidence still comes from clinical trials with heterogeneous designs and endpoints. Future larger controlled trials are needed to better elucidate their role in refractory IMIDs.