Conflict of interest:MKL is an inventor on pending patents related to HLA-A2-specific CARs (PCT/CA2018/051167 and PCT/CA2018/051174). JAS and BTF are inventors on a patent related to the generation of mAbs targeting peptides in the context of MHC (US application no. 15/952,965).

Programmed death-1 (PD-1) inhibits T and B cell function upon ligand binding. PD-1 blockade revolutionized cancer treatment, and although numerous patients respond, some develop autoimmune-like symptoms or overt autoimmunity characterized by autoantibody production. PD-1 inhibition accelerates autoimmunity in mice, but its role in regulating germinal centers (GC) is controversial. To address the role of PD-1 in the GC reaction in type 1 diabetes, we used tetramers to phenotype insulinspecific CD4 + T and B cells in NOD mice. PD-1 or PD-L1 deficiency, and PD-1 but not PD-L2 blockade, unleashed insulinspecific T follicular helper CD4 + T cells and enhanced their survival. This was concomitant with an increase in GC B cells and augmented insulin autoantibody production. The effect of PD-1 blockade on the GC was reduced when mice were treated with a mAb targeting the insulin peptide:MHC class II complex. This work provides an explanation for autoimmune side effects following PD-1 pathway inhibition and suggests that targeting the self-peptide:MHC class II complex might limit autoimmunity arising from checkpoint blockade.

Adoptive immunotherapy with Tregs is a promising approach for prevention or treatment of type 1 diabetes. Islet antigen-specific Tregs have more potent therapeutic effects than polyclonal cells, but their low frequency is a barrier for clinical application. To generate Tregs that recognize islet antigens, we engineered a chimeric antigen receptor (CAR) derived from a monoclonal antibody with specificity for the insulin B-chain 10-23 peptide presented in the context of the IAg7 MHC class II allele present in NOD mice. Peptide specificity of the resulting InsB-g7 CAR was confirmed by tetramer staining and T cell proliferation in response to recombinant or islet-derived peptide. The InsB-g7 CAR re-directed NOD Treg specificity such that insulin B 10-23-peptide stimulation enhanced suppressive function, measured via reduction of proliferation and IL-2 production by BDC2.5 T cells and CD80 and CD86 expression on dendritic cells. Co-transfer of InsB-g7 CAR Tregs prevented adoptive transfer diabetes by BDC2.5 T cells in immunodeficient NOD mice. In wild type NOD mice, InsB-g7 CAR Tregs stably expressed Foxp3 and prevented spontaneous diabetes. These results show that engineering Treg specificity for islet antigens using a T cell receptor-like CAR is a promising new therapeutic approach for the prevention of autoimmune diabetes.

BackgroundDurvalumab is approved for the treatment of lung cancer, advanced biliary tract cancers, and is also being evaluated in many other solid organ tumors. The aim of our study is to define the incidence, etiology, and outcomes of liver injury in consecutive patients receiving durvalumab-based immunotherapy.Patients and methodsDurvalumab treated patients between 1/2016 – 7/2020 were identified from the electronic medical record. Liver injury was defined as serum AST or ALT ≥ 5x upper limit of normal (ULN), ALP ≥ 2x ULN, bilirubin ≥ 2.5 mg/dl, or INR ≥ 1.5. Potential drug induced liver injury (DILI) cases were adjudicated using expert opinion scoring and confirmed with Roussel Uclaf Causality Assessment Method (RUCAM).ResultsAmongst 112 patients, 58 (52%) had non-small cell lung cancer, the median age was 65 years, and 60% were male. The 21 (19%) liver injury patients were significantly more likely to harbor hepatic metastases (52% vs 17%, p=<0.001), experience tumor progression (67% vs 32%, p=0.01) or die (48% vs 11%, p<0.001) during follow-up compared to the 91 without liver injury. Using multivariate regression analysis, the development of liver injury during treatment as well as baseline hepatic metastases were independently associated with mortality during follow-up. Six of the 21 (29%) liver injury cases were adjudicated as probable DILI with four attributed to durvalumab and two due to other drugs (paclitaxel, pembrolizumab). Durvalumab was permanently discontinued in two DILI patients, three received corticosteroids, and one was successfully rechallenged. Only one patient with DILI developed jaundice, and none required hospitalization. Liver biochemistries normalized in all 6 DILI cases, while they only normalized in 27% of the 15 non-DILI cases (p=0.002). The 6 DILI patients also had a trend towards improved survival compared to those with other causes of liver injuryConclusionLiver injury was observed in 19% of durvalumab-treated patients and is associated with a greater likelihood of tumor progression and death during follow-up. The four durvalumab DILI cases were mild and self-limited, highlighting the importance of causality assessment to determine the cause of liver injury in oncology patients receiving immunotherapy.