An Evaluation of the Use of Corticosteroids for the Management of Immune-Mediated Adverse Events in Cancer Patients Treated With Immune Checkpoint Inhibitors.

Immune checkpoint inhibitors (ICIs) have gained prominence for the treatment of a variety of malignancies. However, they are associated with the development of immune-mediated adverse events (IMAEs). Appropriate management of IMAEs and subsequent rechallenging of patients with ICI therapy remains an important area of research. The primary endpoint of this study was to evaluate the efficacy of current prescribing practices and adherence to guideline recommendations for IMAE management. The incidence of symptom resolution, number of patients reinitiated with ICI therapy, and IMAE recurrence upon ICI therapy reinitiation were explored as secondary endpoints. A retrospective chart review within the Allegheny Health Network was conducted in cancer patients treated with ICI therapy who developed a documented ICI-associated IMAE and subsequently received corticosteroid therapy. IRB approval was obtained for this study. Descriptive statistics were used to analyze both primary and secondary endpoints. The study sample was made up of 81 patients. Overall, 50 out of 81 patient cases (62%) were found to be discordant with guideline recommendations; the primary factors identified were inappropriate starting corticosteroid dosing (64%), initiation of a corticosteroid taper prior to IMAE resolution to at least grade 1 severity, and condensed corticosteroid taper (74%). The main IMAEs identified were colitis (28%), pneumonitis (27%), and skin-related inflammation (12%). 76 out of the 81 patients (94%) achieved IMAE resolution; 41 patients (54%) were rechallenged with ICI therapy, of which 14 patients (34%) developed IMAE recurrence. Future studies may focus on evaluating different immunosuppression strategies to optimize IMAE management.

Peripheral Proinsulin Expression Controls Low-Avidity Proinsulin-Reactive CD8 T Cells in Type 1 Diabetes.

Low-avidity autoreactive CD8 T cells (CTLs) escape from thymic negative selection, and peripheral tolerance mechanisms are essential for their regulation. We report the role of proinsulin (PI) expression on the development and activation of insulin-specific CTLs in the NOD mouse model of type 1 diabetes. We studied insulin B-chain-specific CTL from different T-cell receptor transgenic mice (G9Cα-/-) expressing normal PI1 and PI2 or altered PI expression levels. In the absence of PI2 (Ins2-/-), CTL in pancreatic lymph nodes (PLNs) were more activated, and male G9Cα-/- mice developed T1D. Furthermore, when the insulin-specific CTLs developed in transgenic mice lacking their specific PI epitope, the CTLs demonstrated increased cytotoxicity and proliferation in vitro and in vivo in the PLNs after adoptive transfer into NOD recipients. Dendritic cell-stimulated proliferation of insulin-specific T cells was reduced in the presence of lymph node stromal cells (LNSCs) from NOD mice but not from mice lacking the PI epitope. Our study shows that LNSCs regulate CTL activation and suggests that exposure to PI in the periphery is very important in maintenance of tolerance of autoreactive T cells. This is relevant for human type 1 diabetes and has implications for the use of antigen-specific therapy in tolerance induction.