Therapeutic potential of low-dose IL-2 in immune thrombocytopenia: An analysis of 3 cases

Immune thrombocytopenia (ITP) is an acquired immune-mediated disorder with regulatory T cells (Tregs) reduction. Recent studies have shown that low-dose interleukin-2 can preferentially induce regulatory T cell expansion in vivo, and therefore offers a therapeutic strategy against immune thrombocytopenia. We have demonstrated in a previous study that Tregs and platelet counts significantly improve in an adult with ITP following low-dose IL-2 treatment. Here we report the efficacy of low-dose interleukin-2 in another three adults with immune thrombocytopenia who failed the first-line treatment. All patients received a dose of 1.0 million IU IL-2/day for 5 consecutive days per week as a cycle for 2 or 4 weeks. In addition to interleukin-2, Vincristine (2 mg IV weekly×3 weeks) was added to one patient as a combination therapy. No specific treatment was added in the other two patients. Two cases exhibited significantly increased platelet counts with improved levels of regulatory T cells, while no changes were observed for the remaining patient. In summary, administration of daily subcutaneous low-dose interleukin-2 was safe, and it may be a new therapeutic option for treatment of ITP, especially refractory ITP. This article is protected by copyright. All rights reserved.