Hepatocellular carcinoma (HCC) is one of the most frequent tumors worldwide with rising incidence. The inflammatory cytokine, interleukin‐6 (IL‐6), is a critical mediator of HCC development. It can signal through two distinct pathways: the IL‐6 classic and the IL‐6 trans‐signaling pathway. Whereas IL‐6 classic signaling is important for innate and acquired immunity, IL‐6 trans‐signaling has been linked to accelerated liver regeneration and several chronic inflammatory pathologies. However, its implication in liver tumorigenesis has not been addressed yet. Here, we show that IL‐6 trans‐signaling, but not IL‐6 classic signaling, is essential to promote hepatocellular carcinogenesis by two mechanisms: First, it prevents DNA‐damage‐induced hepatocyte apoptosis through suppression of p53 and enhances β‐catenin activation and tumor proliferation. Second, IL‐6 trans‐signaling directly induces endothelial cell proliferation to promote tumor angiogenesis. Consequently, soluble gp130 fused to Fc transgenic mice lacking IL‐6 trans‐signaling are largely protected from tumor formation in a diethylnitrosamine/3,3′,5,5′‐tetrachloro‐1,4‐bis(pyridyloxy)benzene model of HCC. Conclusion: IL‐6 trans‐signaling, and not IL‐6 classic signaling, is mandatory for development of hepatocellular carcinogenesis. Therefore, specific inhibition of IL‐6 trans‐signaling, rather than total inhibition of IL‐6 signaling, is sufficient to blunt tumor initiation and impair tumor progression without compromising IL‐6 classic signaling‐driven protective immune responses. (Hepatology 2017;65:89‐103).

Introduction The Accreditation Council for Graduate Medical Education requires residency programs to support residents' well-being via established policies and programs. Imposter syndrome has been linked to burnout in residents, and understanding how to combat it may help improve resiliency in residents. Methods We held a facilitator-guided, interactive discussion session for internal medicine residents on the topic of imposter syndrome as part of a larger series of discussion sessions on resident wellness. We repeated the session to capture a different group of residents. A psychologist or chief resident led each 30- to 45-minute session with the option to include an attending physician. Residents, faculty, and a clinical psychologist developed instructions for leading this session. At the end of each session, the facilitator provided attendees with a handout with take-home points and an optional postsurvey to assess learning objectives and ask whether they felt this was an effective intervention to promote resident wellness. Results We collected data from 21 residents who attended the small-group discussion sessions. Ninety-six percent of residents felt comfortable recognizing imposter syndrome in themselves, and 62% knew the appropriate next steps after identifying imposter syndrome. Eighty-one percent of residents felt that the imposter syndrome wellness session was an effective intervention to promote resident wellness. Discussion Imposter syndrome has been linked to resident burnout, and discussing imposter syndrome was viewed as an effective intervention to promote resident wellness and resiliency. When creating wellness interventions, other programs should consider addressing imposter syndrome.

Antibody-dependent cellular phagocytosis (ADCP) by macrophages, an important effector function of tumor targeting antibodies, is hampered by ‘Don´t Eat Me!’ signals such as CD47 expressed by cancer cells. Yet, human leukocyte antigen (HLA) class I expression may also impair ADCP by engaging leukocyte immunoglobulin-like receptor subfamily B (LILRB) member 1 (LILRB1) or LILRB2. Analysis of different lymphoma cell lines revealed that the ratio of CD20 to HLA class I cell surface molecules determined the sensitivity to ADCP by the combination of rituximab and an Fc-silent variant of the CD47 antibody magrolimab (CD47-IgGσ). To boost ADCP, Fc-silent antibodies against LILRB1 and LILRB2 were generated (LILRB1-IgGσ and LILRB2-IgGσ, respectively). While LILRB2-IgGσ was not effective, LILRB1-IgGσ significantly enhanced ADCP of lymphoma cell lines when combined with both rituximab and CD47-IgGσ. LILRB1-IgGσ promoted serial engulfment of lymphoma cells and potentiated ADCP by non-polarized M0 as well as polarized M1 and M2 macrophages, but required CD47 co-blockade and the presence of the CD20 antibody. Importantly, complementing rituximab and CD47-IgGσ, LILRB1-IgGσ increased ADCP of chronic lymphocytic leukemia (CLL) or lymphoma cells isolated from patients. Thus, dual checkpoint blockade of CD47 and LILRB1 may be promising to improve antibody therapy of CLL and lymphomas through enhancing ADCP by macrophages.

Blockade of the CD47-SIRPα axis improves lymphoma cell killing by myeloid effector cells, which is an important effector mechanism for CD20 antibodies in vivo. The approved CD20 antibodies rituximab, ofatumumab and obinutuzumab are of human IgG1 isotype. Here, we investigated the impact of the variable regions of these three CD20 antibodies, when they were expressed as human IgA2 isotype variants. We observed more effective direct tumor cell killing by OBI-IgA2 compared to RTX- and OFA-IgA2, which was caspase-independent and required a functional cytoskeleton. Furthermore, IgA2 variants of all three antibodies triggered complement dependent cytotoxicity, with OBI-IgA2 being less effective than RTX- and OFA-IgA2. All three IgA2 antibodies mediated antibody-dependent cellular phagocytosis (ADCP) by macrophages and antibody-dependent cellular cytotoxicity (ADCC) by PMN. Both effector mechanisms were significantly enhanced in the presence of a CD47 blocking antibody or by glutaminyl cyclase inhibition to interfere with CD47-SIRPα interactions. Interestingly, OBI-IgA2 was consistently more potent than RTX- and OFA-IgA2 in triggering ADCC. When we investigated the therapeutic efficacy of the CD20 IgA2 antibodies in different in vivo models, OBI-IgA2 was therapeutically more effective than RTX- or OFA-IgA2. In vivo efficacy required the presence of a functional IgA receptor on effector cells, and was independent of complement activation or direct lymphoma cell killing. These data characterize the functional activities of human IgA2 antibodies against CD20, which were affected by the selection of the respective variable regions. OBI-IgA2 proved particularly effective in vitro and in vivo, which is potentially relevant in the context of CD47-SIRPα blockade.