This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
Rheumatoid factor is directed against- 
Select and explain. 
A. IgG, B. IgD, C. IgM, D. IgA
A: IgG
Answer: A: IgG 
Explanation: harshmohan textbook of pathology *detection of circulating autoantibody called rheumatoid factor against Fc poion of autologous IgG in about 80% of cases