CD Markers
CD18

Author: Nat Pernick, M.D. (see Authors page)

Revised: 23 December 2015, last major update December 2013

Copyright: (c) 2003-2015, PathologyOutlines.com, Inc.

PubMed Search: CD18[title]
Definition / General
  • An integrin which forms the beta 2 chain of CD11a, CD11b, CD11c, CD11d to create a leukocyte adhesion molecule (OMIM #600065)
Terminology
  • Gene is designated ITGB2 (integrin beta 2)
  • Combines with alpha L chain (CD11a) to form the integrin LFA-1
  • Combines with the alpha M chain (CD11b) to form the integrin Mac-1 (macrophage antigen 1, complement receptor 3)
  • Combines with the alpha X chain (CD11c) to form completement receptor 4
  • Also combines with the alpha D chain (CD11d)
Pathophysiology
  • Important for adhesion and signaling in the hematopoietic system (see CD11a-c); also for phagocytosis (J Immunol 2002;169:2003)
Clinical Features
  • Deficiency of the CD18 component (leukocyte adhesion deficiency type 1) is a rare, inherited disorder, causing severe leukocytosis and recurrent severe bacterial infections early in life of skin and mucosal surfaces, possibly fatal, due to defective white blood cell adherence, chemotaxis, phagocytosis and bacterial killing (OMIM #116920, J Clin Immunol 2010;30:756)
  • Note: leukocyte adhesion deficiency type 2 is due to a deficiency in CD15s
  • Reduced expression also seen in Vogt-Koyanagi-Harada (VKH) syndrome (PLoS One 2011;6:e14616)
  • CD11b / CD18 is receptor for Bordetella pertussis adhesin filamentous hemagglutinin (FHA) and for the adenylate cyclase toxin (ACT), which blocks neutrophil function (Infect Immun 2005;73:7317, J Exp Med 2001;193:1035)
  • CD11b / CD18 induces neutrophilic response leading to killing of Steptococcus pyogenes (Eur J Immunol 2005;35:1472)
  • May have role in development of diabetic retinopathy (Int J Ophthalmol 2012;5:202)
Uses by Pathologists
  • No significant clinical use by pathologists
Micro Images

Fibrocytes
(fig A)

Positive Staining - Normal
  • Neutrophils, macrophages, monocytes, NK cells and basophils
Negative Staining - Normal