Larry G. Moss

Background Checkpoint inhibitor immunotherapy is becoming an effective treatment modality for an increasing number of malignancies. As a result, autoinflammatory side-effects are also being observed more commonly in the clinic. We are currently unable to predict which patients will develop more severe toxicities associated with these treatment regimens. Case presentation We present a patient with stage IV melanoma that developed rapid onset autoimmune type 1 diabetes (T1D) in response to combination ipilimumab and nivolumab immunotherapy. At the time of the patient’s presentation with diabetes ketoacidosis, a confirmed anti-GAD antibody seroconversion was noted. Longer-term follow-up of this patient has demonstrated a durable complete response based on PET CT imaging along with a persistently undetectable C-peptide level. Single nucleotide polymorphism gene sequencing and HLA risk allele analysis has revealed the patient to lack any established genetic predisposition to the development of autoimmune T1D. Conclusions While larger studies are necessary to better understand the role of genetic risk factors for the development of autoimmune toxicities in those patients undergoing checkpoint inhibitor immunotherapy, these results suggest that pre-screening patients for known T1D risk alleles may not be indicated. Additional investigation is needed to determine whether an approach such as T cell receptor clonotypic analysis to identify the presence of autoreactive T cell clones may be an effective approach for predicting which patients are at risk for the development of autoinflammatory toxicities while undergoing checkpoint inhibitor immunotherapy.

To address insulin insufficiency, diabetes research has long focused on techniques for replacing insulin-producing β cells. Studies in mice have suggested that, under some conditions, α cells possess the capacity to transdifferentiate into β cells, although the mechanisms that drive this conversion are unclear. In this issue, Bramswig et al. analyzed the methylation states of purified human α, β, and acinar cells and found α cells exhibit intrinsic phenotypic plasticity associated with specific histone methylation profiles. In addition to expanding our understanding of this potential source of β cells, this compendium of carefully generated human gene expression and epigenomic data in islet cell subtypes constitutes a truly valuable resource for the field.