CD Markers
CD11a
CD11a
Table of Contents
Definition / general | Pathophysiology | Clinical features | Uses by pathologists | Microscopic (histologic) images | Positive staining - normal | Positive staining - disease | Negative stainingCite this page: Pernick, N. CD11a. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cdmarkerscd11a.html. Accessed January 15th, 2021.
Definition / general
- Alpha integrin chain at 16p11-13.1 that binds to CD18 and has various leukocyte functions (OMIM #153370)
- Also called integrin alpha L, ITGAL and LFA1 alpha chain (in complex with CD18)
Pathophysiology
- Alpha integrin chain which binds to CD18 and mediates leukocyte adhesion to endothelium, leukocyte trafficking through activated endothelium, lymphocyte blastogenesis, lymphocyte-endothelial cell adhesion, lymphocyte recirculation through lymph nodes, cytotoxic T cell mediated killing and antibody dependent killing by neutrophils and monocytes
- Also mediates binding to unopsonized bacteria (e.g. E. coli) and fungi (e.g. Histoplasma capsulatum)
- With CD18, binds to ICAM1 (CD54), ICAM2 (CD102), ICAM3 (CD50) and ICAM4 (CD242)
- CD11a identifies effector and memory CD8+ T cells, independent of antigen specificity (Oncoimmunology 2013;2:e23972)
- Decreased levels in CD4+ T cells in infants with biliary atresia, due to hypermethylation of CD11a promoter region (Biochem Biophys Res Commun 2012;417:986)
- Increased levels in CD4+ T cells with immune thrombocytopenia (ITP, J Clin Immunol 2011;31:632)
Clinical features
- Anti-CD11a antibody therapy (efalizumab):
- Improves moderate / severe plaque psoriasis (J Cutan Med Surg 2003;7:198, Arch Dermatol 2002;138:591), although may cause progressive multifocal leukoencephalopathy (Neurology 2012;78:458)
- Treatment of macular edema (Invest Ophthalmol Vis Sci 2011;52:6919)
- Treatment of moderate to severe Crohn disease (Dig Dis Sci 2011;56:1806)
- Phase I/II trials pending for immunosuppression in renal transplants (Am J Transplant 2007;7:1770)
- May act by promoting naïve T-cell anergy (J Invest Dermatol 2008;128:2615)
Uses by pathologists
- CD11a deficiency during flow cytometry useful to diagnose acute promyelocytic leukemia (Am J Clin Pathol 2012;138:744)
- CD11a deficiency during flow cytometry useful to diagnose AML-M7, Down syndrome related AML and transient myeloproliferative disease in children with and without Down syndrome (Cytometry B Clin Cytom 2013;84:370)
Microscopic (histologic) images
Images hosted on other servers:
Intestinal mucosa (fig F)
Eruptive papules with efalizumab therapy
Positive staining - normal
- All leukocytes
Positive staining - disease
- Acute promyelocytic leukemia post-treatment (treatment induces expression, Leuk Res 2008;32:315)
Negative staining
- Platelets, various intermediate and high grade lymphomas
