The immunoglobulin level, which is specifically elevated in autoimmune pancreatitis is which of the following?: (A) IgM, (B) IgE, (C) IgG4, (D) IgG2
Answer is C. Serum IgG4 is elevated at least twofold higher than 135 mg/dL in those with autoimmune pancreatitis. Reference: Harrisons Principles of Internal Medicine, 18th Edition, Page 2644