This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Medicine
[{'content': 'Cold haemagglutinin is associated with - \nSelect and explain. \nA. Anti IgM, B. Anti IgG, C. Anti IgA, D. Donath landsteiner antibody', 'role': 'user'}, {'content': 'Answer: A \nExplanation: <p>In cold agglutinin disease, antibody is usually IgM which reacts with red cells poorly or not at all at 37 degree celsius ,whereas it reacts slowly at lower temperature . Donath - Landsteiner antibody is involved in paroxysmal cold hemoglobinuria. Warm antibody immunohemolytic anemiaa are caused by UgH ir rarely ItS antibodies that are active at 37 degree celsius .</p><p>Harrison&;s principles of internal medicine 18 th edition 882.</p>', 'role': 'assistant'}]