title: Early-onset ankylosing spondylitis is associated with a functional MICA polymorphism.
abstract: Major histocompatibility complex (MHC) class I chain-related A (MICA) molecules deliver activating signals through the NKG2D receptor expressed on the surface of natural killer (NK), CD8alphabeta and gammadelta T cells, and the MICA gene is polymorphic. The recently described MICA amino acid substitution at position 129 (MICA-129) seems to affect its binding to NKG2D. We investigated whether this dimorphism (MICA-129met [methionine] and MICA-129val [valine]) is associated with susceptibility to ankylosing spondylitis (AS) in a cohort of Algerian patients stratified according to their HLAB27 status and the age of onset of the disease. DNA from 129 patients and 76 healthy individuals were analyzed to determine the HLA-B generic type as well as MICA-129 polymorphism. Statistical analysis revealed: (1) a weaker association between AS and HLA-B27 in Algerians than in that reported for European patients (63% versus 80-90%), suggesting a possible influence of other genetic/environmental determinants in the studied population and (2) an association between MICA-129 met/met genotype and juvenile AS (p = 0.02) independent of HLA-B27 status. These data suggest a potential role for a functionally relevant MICA gene polymorphism in autoimmune/inflammatory disease susceptibility.
authors.affiliation: Laboratoire d'Immunologie et d'Histocompatibilité CIB-HOB, AP-HP, IUH and INSERM U662, Hôpital Saint-Louis, Paris, France.
authors.forename: Habiba
authors.initials: H
authors.lastname: Amroun
authors.forename: Hachemi
authors.initials: H
authors.lastname: Djoudi
authors.forename: Marc
authors.initials: M
authors.lastname: Busson
authors.forename: Rachida
authors.initials: R
authors.lastname: Allat
authors.forename: Shérif Mohsen
authors.initials: SM
authors.lastname: El Sherbini
authors.forename: Ivan
authors.initials: I
authors.lastname: Sloma
authors.forename: Rajendranath
authors.initials: R
authors.lastname: Ramasawmy
authors.forename: Manuel
authors.initials: M
authors.lastname: Brun
authors.forename: Nicolas
authors.initials: N
authors.lastname: Dulphy
authors.forename: Rajagopal
authors.initials: R
authors.lastname: Krishnamoorthy
authors.forename: Antoine
authors.initials: A
authors.lastname: Toubert
authors.forename: Dominique
authors.initials: D
authors.lastname: Charron
authors.forename: Mohamed Chérif
authors.initials: MC
authors.lastname: Abbadi
authors.forename: Ryad
authors.initials: R
authors.lastname: Tamouza
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D000462:Algeria; D002648:Child; D005260:Female; D020022:Genetic Predisposition to Disease; D015235:HLA-B Antigens / Q000235:genetics; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D013167:Spondylitis, Ankylosing / Q000453:epidemiology / Q000235:genetics*
chemical_list: D015235:HLA-B Antigens; D015395:Histocompatibility Antigens Class I; C099187:MHC class I-related chain A