Langerhans cell shows which of these?
**Question:** Langerhans cell shows which of these?
*A. Immunopositivity for CD1a*
*B. Immunopositivity for CD207*
*C. Immunopositivity for CD45RO*
*D. Immunopositivity for CD68*
**Correct Answer:** B. Immunopositivity for CD207
**Core Concept:** Langerhans cells are a type of antigen-presenting cell (APC) that play a crucial role in the immune response, particularly in skin immunity. They are derived from hematopoietic stem cells and express various surface markers.
**Why the Correct Answer is Right:** CD207, also known as Langerin, is a C-type lectin receptor that is selectively expressed on Langerhans cells. It is involved in the recognition of pathogens and the activation of immune responses, making CD207 the appropriate marker for identifying Langerhans cells in histopathology slides.
**Why Each Wrong Option is Incorrect:**
A. Immunopositivity for CD1a: CD1a is another surface marker expressed on Langerhans cells, but it is not specific enough to identify LCs alone, as it is also expressed on dendritic cells and macrophages.
B. Immunopositivity for CD45RO: CD45RO is a leukocyte common antigen that is expressed on various leukocytes like T cells, B cells, and monocytes. It is not specific for Langerhans cells.
C. Immunopositivity for CD45RO: Same explanation as option B, as CD45RO is not specific for Langerhans cells.
D. Immunopositivity for CD68: CD68 is a pan-macrophage marker that is expressed on various macrophages, including Langerhans cells. However, it is not specific for Langerhans cells alone.
**Clinical Pearl:** Understanding the immunophenotype of Langerhans cells is essential for interpreting histopathology slides correctly. CD1a and CD68 are commonly used markers for identifying Langerhans cells, but CD207 (Langerin) is the most specific marker for Langerhans cells.