A 46-year-old man has a 4-week history of epigastric pain; test of stool is positive for occult blood. Examination of tissue obtained on biopsy of the gastric antrum shows curved bacterial rods. Which of the following additional findings is most likely?
b. Antiparietal cell antibodies
c. Cholecystitis with antral seeding
d. Immunodeficiency state
e. Increased urease activity in the antrum