Which infectious disease is marked by increased numbers of mononuclear leukocytes and enlarged cervical lymph nodes?

• A. Mononucleosis
• B. Systemic lupus erythematosus
• C. Lymphedema
• D. Celiac disease

Answer: (A)

Infectious mononucleosis is the infection that shows a rise in lymphocytes (mononuclear leukocytes) and prominent cervical lymph node enlargement. Epstein-Barr virus, which often causes mono, infects B cells and triggers a strong T‑cell response, leading to lymphocytosis with reactive/atypical lymphocytes and swollen neck nodes. Clinically, you often see fever, sore throat, fatigue, and sometimes splenomegaly, with lab tests highlighting elevated lymphocytes rather than neutrophils. The other conditions aren’t infectious diseases characterized by this specific pattern of mononuclear leukocytosis plus cervical lymphadenopathy.