Six years ago, researchers from Kobe University discovered a new condition caused by an autoimmune reaction against PIT-1, a pituitary-specific transcription factor that is primarily involved in producing growth hormone (GH), thyroid stimulation hormone (TSH), and prolactin (PRL). This week, the same scientists uncovered evidence showing that the condition is caused by tumors in the thymic gland.
During their discovery of the new autoimmune disease, Kobe University researchers found anti-PIT-1 antibodies in the blood of patients with the apparent disease. Accordingly, they called the disease “anti-PIT-1 antibody syndrome,” but at the time they did not know what was causing the immune system to become intolerant to the PIT-1 transcription factor.
Their new study, published in the journal Scientific Reports, revealed the one component consistently present in a variety of anti-PIT-1 antibody syndrome cases: the detection of a thymoma, a tumor originating in the thymic gland. PIT-1 was found to be abnormally expressed within the detected thymomas, and cytotoxic T cells of the immune system were mistakenly designed to target PIT-1. Together, these two events triggered an autoimmune reaction characteristic of what the scientists called anti-PIT-1 antibody syndrome.
Hypopituitarism, which appears to occur as a result of anti-PIT-1 antibody syndrome, dampens the activity of the pituitary gland, which is located at the base of the brain and regulates several hormones. The recent discovery from Kobe University offers researchers an opportunity to develop new treatments for both anti-PIT-1 antibody syndrome and similar autoimmune diseases.
"Around 20% of hypopituitarism cases are caused by unknown factors. This discovery has clarified one of the causes," said Associate Professor Takahashi. "We hope that this discovery will contribute to more effective diagnosis and treatment for patients suffering from autoimmune pituitary diseases, hypopituitarism, and thymomas."