This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Misc. (W.B.C), Subject name: Pathology
Infectious mononucleosis affects? 
Select and explain. 
A. B-cells, B. T-cells, C. NK cells, D. Macrophages
A: B-cells
Answer: A: B-cells 
Explanation: Ans. (a) B-cells(Ref: Wintrobe's 12th/pg 1589-1593)Pathogenesis of Infectious Mononucleosis: Caused by Ebstein Barr Virus (EBV) Q infectionEntry of EBV in the oral cavity QEBV initially infects oral epithelial cells a symptoms of pharyngitis. QIntracellular Q viral replication and cell lysis with release of new virionsVirus spreads to contiguous structures such as the salivary glands QEventual viremia & infection of B lymphocytes Q in the peripheral blood & entire lymphoreticular system, including liver & spleen.DOWNY cells are atypical CD8+ T lymphocytes that are characteristic of infectious mononucleosis QDOWNY cells exhibit both suppressor & cytotoxic Q functions that develop in response to the infected B lymphocytes.