CTLA4 and hypothyroidism: In addition, TSH serum may be slightly higher in nonthyroid-related pathologies such as the following: morbid obesity, autoimmune disease, medications that cause hypothyroidism—such as amiodarone, lithium, interferon, antidopaminergics [1], bexarotene, corticosteroids, anti-CTLA4, and anti-PD-1 [28, 29]—all of which may modify thyroid tests, and also by interference from antibodies such as heterophils [30].