Rheumatoid factor is best described as which of the following?
1An IgG antibody directed against the Fab portion of IgM
2An antibody directed against nuclear antigens of the host cell
3A complement component that is consumed during active systemic inflammation
4An antibody, most often IgM, directed against the Fc portion of IgG✓ 정답
해설
Rheumatoid factor is an antibody directed against the Fc portion of the patient own IgG, and it is most often of the IgM class. Distractors frequently reverse the direction of this relationship, so remember precisely which molecule targets which.