Intravenous Anakinra for Macrophage Activation Syndrome May Hold Lessons for Treatment of Cytokine Storm in the Setting of Coronavirus Disease 2019.

Macrophage activation syndrome (MAS) and hemophagocytic lymphohistiocytosis (HLH) are increasingly recognized as being on a continuum of cytokine storm syndromes, with different initiating pathways culminating in cytotoxic dysfunction and uncontrolled activation and proliferation of T lymphocytes and macrophages. The activated immune cells produce large amounts of proinflammatory cytokines, including interleukin 1β (IL)-1β. Management depends on the recognized diagnosis. In the setting of a cytokine storm syndrome and infection, collaborative involvement of specialists, including infectious disease and rheumatology is ideal. Anakinra, a recombinant IL-1 receptor antagonist, has been used subcutaneously and intravenously in pediatric patients and is considered a first-line treatment for MAS and secondary HLH (sHLH) among many pediatric rheumatologists. Previous reports of anakinra used in adults for treatment of MAS or sHLH are limited to subcutaneous administration. In this issue, Moneagudo et al. present a series of adult patients with sHLH treated with intravenous anakinra, including patients in whom subcutaneous anakinra was insufficient. As the authors suggest, there is a potential therapeutic use for anakinra in sHLH or the cytokine storm syndrome triggered by COVID19. Trial design will be key, with the patient subpopulation, timing of intervention, and doses tested important.