Résumé
The increased use of immune checkpoint inhibitors (ICIs) has revealed rare and poorly described emerging side effects, such as hemophagocytic lymphohistiocytosis (HLH). Our study aims at precisely describing ICI-induced HLH cases and comparing them to HLH cases secondary to other aetiologies. Methods: a national call for observations was made to University Hospitals (CHU) and Cancer Centers in France for cases of HLH occurring under ICIs. The comparative cohort was made of HLH cases secondary to hematologic malignancies, solid neoplasms and autoimmune diseases. Descriptive analyses were performed in the HLH-ICI cohort, and comparative analyses on the clinico-biological characteristics and survival between the two cohorts. Results: the HLH-ICI cohort included 29 patients, the HLH cohort related to hematologic malignancies/solid neoplasms (HLH-HN) included 25 patients, and the HLH cohort related to autoimmune diseases (HLH-AID) included 10 patients. Combination therapy (anti-PD1 + anti-CTLA4) concerned 51.7% of cases. HLH occurred early (89.8% of cases within the first four injections). Melanoma was the most represented cancer (55.2%). Comparative analyses between the HLH-ICI and HLH-AID cohorts showed similar clinico-biological characteristics and similar fatality rate, unlike the HLH-HN cohort which was statistically different. The HLH-related mortality rate was approximately 13.8% in the HLH-ICI cohort. The most used treatment in the HLH-ICI cohort was corticosteroid therapy, alone in 71.43% of cases. Conclusion: this study tends to show that HLH secondary to ICIs resembles in their characteristics and survival HLH secondary to autoimmune diseases, more than paraneoplastic HLH. Treatment with corticosteroid therapy alone seems sufficient in most cases.