CO13 | Macrophage activation syndrome successfully treated with eculizumab and emapalumab: a case report

C. Ferrari, L. Castelnovo, L. Marchionni, P. Faggioli, A. Mazzone | ASST Ovest Milanese, Ospedale di Legnano (MI), Italy

Premises: Hemophagocytic lymphohistiocytosis is a hyperinflammatory syndrome. If it occurs in autoimmune diseases the term macrophage activation syndrome is used. Infections represent a trigger of acute episode.
Description of the Case report: A 45-year-old women suffering from Crohn’s disease complicated by polimyositis, treated with DMARDs and steroids and, since Sept. 2023 with infliximab, in Dec.2023 was recovered for fever. Blood tests showed: pancytopenia, hyperferritinemia, hypertransaminasemia, increase in LDH, triglycerides, CPK and inflammation indices; complement consumption. MAS was confirmed by examination of the bone marrow. We documented possible recent EBV and M. pneumoniae infections. Therapy with high dose streoids, anakinra and IVIg was established; she was treated with antibiotics, antivirals and antifungals. Due to the persistence of signs of thrombotic microangiopathy we decided to start association therapy with eculizumab, a mAb designed to attach to the C5 complement protein, with stabilization but missed improvement, so the patient was treated with emapalumab, with clinical improvement and normalization of LDH, complement and fibrinogen.
Conclusions: The treatment of HLH consists of glucocorticoids, anakinra and IVIg. Treatment of the underlying disease should be carried out in parallel. Emapalumab is the first targeted therapy approved by the US FDA for primary pediatric HLH. Ours is one of the first reports of the use of Emapalumab in adult patients: this drug has proven to be effective for a pathology burdened by a very high mortality rate.