WBR0141

Author	[[PageAuthor::Rim Halaby, M.D. [1]]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Immunology
Sub Category	SubCategory::General Principles
Prompt	[[Prompt::Neutrophils are critically involved in the inflammation process. The process of leukocyte movement from the blood to the tissues through the blood vessels is known as extravasation, and can be divided up into a number of broad steps. Which of the signaling mediators is involved in the migration of the neutrophils across the endothelial cells?]]
Answer A	AnswerA::E selectin and P selectin
Answer A Explanation	[[AnswerAExp::E selectin and P selectin are involved in the rolling phase.]]
Answer B	AnswerB::ICAM 1
Answer B Explanation	[[AnswerBExp::ICAM-1 is involved in the tight binding of neutrophils to the endothelium.]]
Answer C	AnswerC::PECAM 1
Answer C Explanation	[[AnswerCExp::PECAM-1 is involved in diapedesis, which is the migration of the leukocytes across the endothelial cells.]]
Answer D	AnswerD::C5a
Answer D Explanation	[[AnswerDExp::C5 a is involved in the migration of leykocytes through the interstitum towards the site of inflammation.]]
Answer E	AnswerE::Interleukin 8
Answer E Explanation	[[AnswerEExp::Interleukin 8 is involved in the migration of leukocytes through the interstitium towards the site of inflammation.]]
Right Answer	RightAnswer::C
Explanation	[[Explanation:: Educational Objective: Inflammation involves several steps including the rolling phase of the neutrophils, their binding to the endothelium, diapedesis and migration to the site of inflammation. PECAM 1 is involved in diapedesis, which is the migration of the leukocytes across the endothelial cells. References: First Aid 2014 page 224]]
Approved	Approved::No
Keyword	WBRKeyword::Inflammation, WBRKeyword::Diapedesis, WBRKeyword::Leukocyte, WBRKeyword::Leukocyte adhesion, WBRKeyword::Endothelium, WBRKeyword::Endothelial cell
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::