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
[{'content': 'Acquire IgA deficiency may occur in ? \nSelect and explain. \nA. Severe Congenital toxoplasmosis, B. Severe Measles infection, C. Severe Brucellosis, D. Severe Leptospirosis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Severe Congenital toxoplasmosis Block in B cell differentiation due to defective interaction between T and B cells. Naive B cells are not able to differentiate into IgA - producing cells.', 'role': 'assistant'}]