Coexistence of Immune Checkpoint Inhibitor-Induced Autoimmune Diabetes and Pancreatitis.

Autoimmune diabetes is a rare but severe endocrine toxicity induced by immune checkpoint inhibitor (ICI) treatment. It is unclear if ICI causes selective islet toxicity or non-selective pancreas toxicity. We analyzed 11 patients treated with ICI who developed ICI-related autoimmune diabetes. Eight patients had lipase and/or amylase tested on the same day of diagnosis of autoimmune diabetes. Among them, 75% (6/8) had normal lipase and 100% (6/6) had normal amylase. There was no correlation between glucose level at onset and biochemical pancreatitis. We characterized the clinical features of ICI-induced autoimmune diabetes. Fifty-five percent (6/11) of patients tested positive for GAD65 autoantibodies, and 55% (6/11) developed diabetic ketoacidosis at manifestation of hyperglycemia. In all 11 patients, C-peptide levels were low in the presence of hyperglycemia. ICI-induced thyroiditis was found in 64% (7/11), of which 36% (4/11) were newly diagnosed with thyroiditis while the remaining 27% (3/11) had pre-existing hypothyroidism followed by ICI-induced thyroiditis. Additionally, 27% (3/11), developed ICI-induced hypophysitis. Thyroiditis and autoimmune diabetes coexisted in all patients with ICI-induced hypophysitis. The median time from ICI treatment to the onset of autoimmune diabetes was 11 weeks. Our data suggest that few patients had coexistent ICI-induced autoimmune diabetes and pancreatitis, suggesting ICI mainly caused selective islet toxicity.

Amelioration of Murine Autoimmune Pancreatitis by Targeted LTßR Inhibition and Anti-CD20 Treatment.

Autoimmune pancreatitis (AIP) is a rare form of chronic pancreatitis, for which treatment options, especially the long-term management, are limited. The only therapy that has been established and accepted so far is corticosteroids, but the relapse rate is significant. In the current study, we discern the effector mechanisms of targeted LTßR pathway inhibition using LTßR-Ig. Furthermore, the efficacy of LTßR-Ig therapy is compared with the depletion of immune cell subsets (CD4+ and CD20+), which are suggested to play a pathological role in AIP development. Three well-established mouse models of AIP were used to examine treatment efficacies and mechanisms. Tg(Ela1-Lta,b) mice represent a genetic model, in which AIP develops spontaneously. In MRL/Mp and IL-10-/- mice, AIP is induced by repeated polyinosinic:polycytidylic acid injection. Mice with AIP were treated with anti-CD20, anti-CD4 mAbs, or targeted LTßR-Ig. LTßR-Ig and anti-CD20 treatment led to significant improvement of AIP, including a decrease in autoantibody production and pancreatic inflammation in Tg(Ela1-Lta,b) and IL-10-/- mice. The molecular mechanism of this beneficial effect possibly involves the downregulation of Stat3 and noncanonical NF-κb activation. Anti-CD4 treatment reduced Th1 and Th2 signature but did not alleviate AIP. Additionally, in contrast to anti-CD20 or anti-CD4 treatments, blocking LTßR signaling disrupted tertiary lymphoid organs in all three models. We demonstrate that treatment with LTßR-Ig or anti-CD20 Ab alleviated murine AIP. LTßR-Ig treatment for AIP was effective in both lymphotoxin-dependent and lymphotoxin-independent AIP models, possibly because of its dual anti-inflammatory and antiautoimmune mechanisms.