ASCP Medical Laboratory Technician (MLT) 2025 – 400 Free Practice Questions to Pass the Exam

Reactive lymphocytosis is an increase in the number of lymphocytes in the blood, which often occurs in response to infections, particularly viral infections. Epstein-Barr virus (EBV) infection is most commonly associated with reactive lymphocytosis, as it is known to cause infectious mononucleosis. In this condition, the body mounts an immune response characterized by an increase in atypical lymphocytes, which are activated B cells responding to the infection.

While other infections such as HIV, viral hepatitis, and influenza can also lead to lymphocyte changes, they do not typically present with the same pronounced lymphocytic response as seen with EBV infection. For instance, HIV can lead to a progressive loss of CD4 T-helper cells, and while there may be some lymphocyte elevation, it is generally not the hallmark of the infection. Viral hepatitis characteristically shows a rise in liver enzymes and inflammation in the liver rather than a significant rise in lymphocytes. Similarly, influenza viruses cause respiratory symptoms and primarily activate different arms of the immune system, which may not lead to reactive lymphocytosis in the same manner.

Therefore, the connection between EBV infection and reactive lymphocytosis is well established, making it the most accurate choice in this context.