Which cell is characteristically increased in the peripheral smear of a patient with infectious mononucleosis?

In infectious mononucleosis, the peripheral blood smear typically shows an increased number of atypical lymphocytes. This condition is often caused by the Epstein-Barr virus (EBV), which triggers a strong immune response, predominantly involving T-lymphocytes. These atypical lymphocytes are usually larger and have more abundant cytoplasm compared to normal lymphocytes, reflecting their activation and response to the viral infection.

The presence of these atypical lymphocytes is a key diagnostic criterion for infectious mononucleosis. It is important to recognize this feature on a peripheral blood smear, as it aids in distinguishing the infection from other conditions that may present similarly, such as acute viral hepatitis or other viral infections.

Understanding the role of lymphocytes in the immune response to EBV and their morphological characteristics in the context of infectious mononucleosis is crucial for healthcare professionals engaged in hematology and clinical diagnosis.