This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
Graves disease is an example of which type ...... immunologic response- 
Select and explain. 
A. Type I, B. Type II, C. Type III, D. Type IV
B: Type II
Answer: B: Type II 
Explanation: Ans. is 'b' i.e., Type II . Type II hypersensitivity may involve three different antibody -dependent mechanisms. I. Opsonization --> Complement and Fc receptor mediated phagocytosis. Transfusion reactions Autoimmune hemolytic anemia/agranulocytosis/ thrombocytopenia. Erythroblastosis fetalis. 2. Complement and Fc - receptor mediated inflammation Glomerulonephritis Vascular rejection 3. Antibody mediated cellular dysfunction Upregulation --> Graves disease Down regulation ______ > Myasthenia gravis Sometimes, antibody causes stimulation instead of damage for example in Grave's disease long acting thyroid stimulator (LATS), an antibody against some determinant on thyroid cells, stimulates excessive secretion of thyroid hormone. Such antibody mediated cell stimulation has also been called type V hypersensitivity.