Problem:
A 2-year-old boy suffering from repeated painful bouts of inflammation of mucosal surfaces, especially affecting the lips, is brought to the pediatrician's office. The mother remembers similar symptoms in previous generations of her family and fears a heritable tendency toward food allergy. What laboratory finding would best support the physician's suspicion? Need Assignment Help? (A) Depressed C3 (B) Depressed C4 (C) Depressed C5 (D) Elevated C1 (E) Elevated C1, C4, and C