USMLE Forums banner
1 - 3 of 3 Posts

Ex-USMLE Forums Staff
753 Posts
Discussion Starter · #1 · (Edited)
The title of this message could well constitute a buzzword. It's a very classical description of the autosomal recessive disorder Leukocyte Adhesion Deficiency.
Newborns presents with omphalitis and delayed sloughing with frequent bacterial infections.
However, abscesses do not occur as the neutrophils lack the ability to adhere to the endothelium because of a defective integrin molecule also called CD18.
More specifically the defective gene (on chromosome 21) encodes for beta2 integrin subunit that is found in all three integrin molecules namely LFA1, MAC1, and VLA4.
Once the diagnosis is suspected a series of immune tests carried until finally the CD18 is found missing.
One of the characteristics of the disease is the extreme leukocytosis seen in this patient as the neurtrophils are unable to leave the blood vessels.

It's important not confuse CD18 with CD34, CD34 is present on the endothelial surface of venules and it binds the L-selectin on T lymphocytes calling them to home in (circulating Naive lymphocytes either find their target antigen or go HOME via the process of homing into secondary lymphoid). organs).
1 - 3 of 3 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.