A febrile 12-year-old child presents with severe right lower quadrant
pain that is interpreted by the attending physician as acute appendicitis.
The patient has also been complaining of joint pain. At laparotomy, the
surgeon notes that the appendix is normal; however, the mesenteric lymph nodes are markedly enlarged and contain focal areas of microabscess formation on cut section. This patient is most likely

A. an asthmatic
B. deficient in C1 esterase inhibitor activity
C. HLA-B27 positive
D. leukopenic
E. serologically positive for toxoplasmosis