Systematic comparison with autoimmune liver disease identifies specific histological features of immune checkpoint inhibitor-related adverse events.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have become a mainstay of cancer treatment. Their immune-boosting quality has one major drawback, their proclivity to induce a broad array of immune-related adverse events (irAEs) affecting, among others, the liver and sharing some similarities with classic autoimmune liver diseases (AILD).We aimed to compare clinical, laboratory and histological features of patients with liver-related irAEs and AILD. METHODS: We systematically compared liver irAEs with AILD, namely autoimmune hepatitis (AIH) and primary biliary cholangitis, regarding their clinical, laboratory, and histological features. RESULTS: Twenty-seven patients with liver irAEs (ICI group) and 14 patients with AILD were identified. We observed three distinct ICI-induced histological liver injury patterns: hepatitic (52%), cholangitic (19%), and mixed (29%). When comparing the ICI and AILD groups, centrilobular injury as well as granuloma formation were more prevalent in the former (p=0.067 and 0.002, respectively). CD4+/CD8+ T cell ratios were heterogeneous between the two groups, without statistically significant difference but with a trend toward increased CD8+ T cells among hepatitic irAEs as compared with AIH. Pattern of liver function test alteration was predictive for the type of irAEs but did not correlate with histological severity. CONCLUSIONS: Liver irAEs have broad clinical, laboratory and histological presentations. Histological features of irAEs and AILD are distinct, likely underpinning their different immunological mechanisms.

[Short telomere syndrome in adults: a rare entity that should be evoked]. / Syndrome des télomères courts chez l'adulte†: une entité rare qu'il faut savoir évoquer.

Short telomere syndrome (STS) is a group of rare, often underrecognized, diseases caused by defects in telomere-maintenance genes, leading to abnormal telomere shortening and associated with diverse multi-organ manifestations. In pediatric patients, STS typically presents with mucocutaneous or gastrointestinal lesions, bone marrow failure and neoplasia. In adulthood, aplastic bone marrow disease, liver disease and pulmonary fibrosis are classic clinical manifestations. At present, medical treatment options for STS remain limited. Danazol, a synthetic androgenic hormone, can slow down telomere shortening and thus limit the progression of the disease. Finally, hematopoietic, hepatic and pulmonary transplantation, sometimes combined, may be discussed in a multidisciplinary setting in certain situations.

Le syndrome des télomères courts (STC) est un groupe de maladies rares dues à un défaut dans les gènes de maintenance des télomères, provoquant leur raccourcissement anormal et des manifestations cliniques multiorganiques. Dans l'enfance, le STC se présente par des lésions mucocutanées et gastro-intestinales, une insuffisance médullaire et des néoplasies. À l'âge adulte, une atteinte médullaire aplasiante, hépatique, et une fibrose pulmonaire sont des manifestations cliniques classiques. Les options thérapeutiques pour le STC restent limitées. Le danazol, une hormone androgène synthétique, permet, parfois, de freiner le raccourcissement télomérique et de limiter la progression de la maladie. Finalement, les transplantations hématopoïétique, hépatique et pulmonaire sont discutées dans certaines situations de manière multidisciplinaire.

Resident Kupffer cells and neutrophils drive liver toxicity in cancer immunotherapy.

Immunotherapy is revolutionizing cancer treatment but is often restricted by toxicities. What distinguishes adverse events from concomitant antitumor reactions is poorly understood. Here, using anti-CD40 treatment in mice as a model of TH1-promoting immunotherapy, we showed that liver macrophages promoted local immune-related adverse events. Mechanistically, tissue-resident Kupffer cells mediated liver toxicity by sensing lymphocyte-derived IFN-γ and subsequently producing IL-12. Conversely, dendritic cells were dispensable for toxicity but drove tumor control. IL-12 and IFN-γ were not toxic themselves but prompted a neutrophil response that determined the severity of tissue damage. We observed activation of similar inflammatory pathways after anti-PD-1 and anti-CTLA-4 immunotherapies in mice and humans. These findings implicated macrophages and neutrophils as mediators and effectors of aberrant inflammation in TH1-promoting immunotherapy, suggesting distinct mechanisms of toxicity and antitumor immunity.