Hemophagocytic Lymphohistiocytosis Due to Ipilimumab plus Nivolumab in a Patient with Pleural Mesothelioma

Background. Hemophagocytic lymphohistiocytosis (HLH) is a fatal immune response syndrome characterized by abnormal hyperinflammatory and hyperferritinemia. Case. A patient in their 50s received combination ipilimumab plus nivolumab for recurrent pleural mesothelioma. Eight days after the start of immune checkpoint inhibitor treatment the patient was admitted to our hospital with a chief complaint of fever and gross hematuria. Although the patient was treated with antibiotics, their general condition began to worsen from the 11th day after admission. The patient was diagnosed with cytokine release syndrome and HLH and was treated with systemic corticosteroids and mycophenolate mofetil. Platelet transfusions for thrombocytopenia and continuous hemodiafiltration for acute renal failure were required. The patient gradually improved and was discharged from the hospital on the 39th day after admission. Conclusion. It should be noted that HLH is relatively frequent and can be serious in patients who receive combination therapy with ipilimumab plus nivolumab. An early diagnosis and administration of systemic corticosteroids and immunosuppressive agents is crucial when HLH is suspected during cancer immunotherapy.