Bryan Johnson’s chronic disease is notoriously difficult to diagnose By Sarah Todd July 8, 2026 0 min Stat News Share Summary Takeaways Listen Insight Report Quiz Top Institutions 1 Bryan Johnson announced he has autoimmune gastritis, a chronic condition where antibodies destroy stomach acid-producing cells. 2 Autoimmune gastritis affects about 4% of the global population and is often misdiagnosed due to its insidious nature. 3 Diagnosis typically requires an upper endoscopy with biopsies, especially for patients with low ferritin levels. 4 Current treatments focus on managing symptoms and monitoring for stomach cancer, as effective cures are lacking. 5 Johnson's team is exploring experimental therapies like CAR-T therapy, which has not been extensively studied for autoimmune gastritis.