Which complement finding is most consistent with active immune complex disease?
1Increased C3 and C4
2Decreased C3 and C4✓ 정답
3Normal C3 with absent C1 inhibitor
4Increased total hemolytic complement
해설
Immune complexes activate the classical pathway, consuming complement, so both C3 and C4 decrease. These levels are used to follow disease activity. Increased levels may simply reflect a nonspecific acute phase response, so the direction of change matters.