What percentage of cells in the lymph node biopsy showed CD3 expression associated with normal T lymphocytes?

• A. 0%
• B. 3%
• C. 70%
• D. 40%

Answer: (B)

The correct choice indicates that 3% of the cells in the lymph node biopsy showed CD3 expression associated with normal T lymphocytes. This suggests a significant but low presence of T cells in the sampled tissue. Typically, lymph nodes are rich in T lymphocytes, which are integral to the immune response. They express CD3, a marker associated with T cell activation and differentiation.

In a normal lymph node, one would expect a higher proportion of CD3-positive T lymphocytes. The context suggests that there may be an underlying pathology or dysfunction, leading to a diminished representation of T cells in this biopsy. A percentage as low as 3% may indicate various conditions, including immunosuppression, lymphoid tissue involution, or even certain types of lymphoma where T cell populations are altered or reduced.

Understanding the typical expression of CD3 in T lymphocytes can provide insight into immune system function or pathology, which is essential for diagnosing and managing various health conditions. In this specific scenario, the finding of only 3% highlights a notable deviation from the norm, warranting further investigation into the patient's health status.