Autoimmune Drug Shows Promise in Reversing Immunotherapy-Induced Diabetes

Researchers at UCLA Health's Jonsson Comprehensive Cancer Center have discovered a promising new approach to tackling one of the rare but severe side effects of cancer immunotherapy—immune checkpoint inhibitor–induced type 1 diabetes. This condition, which can be life-threatening, results from the immune system attacking insulin-producing cells in the pancreas. The team found that an existing autoimmune medication could potentially prevent, and even reverse, this autoimmune attack.

The study, published in JCI Insight, revealed that a previously unrecognized subset of immune cells, called CD4+ T follicular helper (Tfh) cells, play a crucial role in driving the autoimmune destruction of pancreatic beta cells during immunotherapy. These cells produce signaling molecules IL-21 and interferon gamma (IFNγ), which fuel and sustain the immune assault.

To explore therapies, the researchers tested JAK inhibitors—drugs already approved by the FDA for conditions such as psoriasis and arthritis—that block IL-21 and IFNγ pathways. In mouse models, treatment with these inhibitors prevented the onset of diabetes and, in some cases, restored normal blood sugar levels by reducing the number of Tfh cells and halting the autoimmune process.

Lead author Dr. Melissa Lechner emphasized the significance: “This is the first study to identify Tfh cells and their pathways as key drivers of checkpoint inhibitor–induced type 1 diabetes. The fact that these pathways can be targeted with approved drugs without compromising cancer-fighting immunity is a major breakthrough.”

This research not only advances understanding of the autoimmune side effects associated with immune checkpoint inhibitors like pembrolizumab and nivolumab but also offers hope for protective strategies. Since these drugs are effective in activating the immune system against tumors, finding a way to prevent their toxicities could significantly improve patient outcomes.

Autoimmune complications from immunotherapy, especially type 1 diabetes, though rare, are becoming increasingly recognized. Around 1–2% of patients develop this condition, with a large proportion requiring intensive care and lifelong insulin dependence.

The study also discovered that similar immune cell mechanisms may underlie other autoimmune toxicities caused by checkpoint inhibitors, suggesting a common pathway that could be targeted to prevent multiple side effects.

Future efforts are focused on initiating clinical trials to validate these findings in patients. The goal is to develop treatments that allow more patients to benefit from immunotherapy without risking severe autoimmune damage, especially those with pre-existing autoimmune conditions who are often excluded from current trials.

This discovery marks a significant step toward safer cancer immunotherapy and highlights the potential of existing autoimmune medications to mitigate treatment-related toxicities, improving long-term patient care.

(Source: https://medicalxpress.com/news/2025-07-common-autoimmune-drug-reverse-immunotherapy.html)