Background Allogeneic mesenchymal stem cells (MSC) transplantation showed therapeutic effect in active and refractory systemic lupus erythematosus (SLE).

Objectives To determine the long-term safety and efficacy of allogeneic MSC transplantation (allo-MSCT) in severe SLE patients refractory to previous therapies.

Methods All consecutive SLE patients who received at least one allo-MSCT were analyzed. SLEDAI score of more than or equal to 8 or with at least one BILAG grade A or at least two BILAG grade B manifestations. All the patients were refractory to corticosteroid and/or immunosuppressive drugs treatment. Allogeneic bone marrow and/or umbilical cord derived MSCs were infused intravenously, with one million cells per kilogram of bodyweight for each infusion. The primary end point was 5-year overall survival. Secondary end points included complete clinical remission, partial clinical remission and relapse.

Results Eighty-one patients were enrolled and underwent allo-MSCT. Thirteen patients died within 5 years post-MSCT and the 5-year overall survival rate was 84% (68/81). At 5-year follow-up, 22 patients (22/68, 32%) were in complete clinical remission and another 6 patients (6/68, 9%) were in partial clinical remission, and the 5-year disease remission was 41% (28/68). In total, 37 patients had achieved clinical remission (27 in complete remission and 10 in partial remission) at the 5 years visit and then 9 patients subsequently relapsed. The 5-year overall rate of relapse was 24% (9/37). SLEDAI scores, levels of serum albumin and complement C3, peripheral white blood cell and platelet numbers, as well as proteinuria levels continued to improve during the follow-up.

Conclusions Allogeneic MSCT is safe and resulted in long-term clinical remission in severe and drug-resistant SLE patients.

Disclosure of Interest None declared