Infectious mononucleosis affects
**Core Concept**
Infectious mononucleosis, also known as glandular fever, is a viral illness caused by Epstein-Barr virus (EBV). It primarily affects the lymphoid tissues and is characterized by fever, sore throat, and lymphadenopathy.
**Why the Correct Answer is Right**
The correct answer is related to the primary target of EBV infection, which is the lymphoid cells, particularly the B lymphocytes. EBV infects and transforms these cells, leading to an abnormal proliferation of B lymphocytes. This abnormal proliferation results in the clinical manifestations of infectious mononucleosis, including fever, sore throat, and lymphadenopathy.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because EBV primarily affects the lymphoid cells, not the epithelial cells.
**Option B:** Incorrect because EBV is a viral infection, not a bacterial infection.
**Option C:** Incorrect because EBV is not a type of autoimmune disease, but rather a viral infection that triggers an abnormal immune response.
**Clinical Pearl / High-Yield Fact**
The diagnosis of infectious mononucleosis is often confirmed by the presence of specific antibodies against EBV, such as heterophile antibodies or EBV-specific IgM antibodies. This is particularly useful in cases where the clinical presentation is atypical.
**Correct Answer: C. Lymphoid cells.**