MHC class I region plays a role in the development of diverse clinical forms of celiac disease in a Saharawi population.
OBJECTIVE
The aim of this study was to investigate the association of MHC genes in the development of celiac disease (CD) and its diverse clinical forms in a Saharawi population.


METHODS
One hundred and twenty-five CD patients and 98 healthy controls were selected from the Saharawi refugee camps in Tindouf. All were investigated for the presence of antitransglutaminase 2 antibodies. Patients were divided into two groups according to their clinical manifestations: 70 typical and 55 atypical. Patients and controls were typed for HLA-B, DRB1, DQB1, and DQA1, and for MICA transmembrane polymorphism.


RESULTS
The frequency of HLA-DQ2 in Saharawi controls was notably increased compared with other populations. No differences in the distribution of DQ2 in either group of patients were found. However, the haplotype B8/DR3/DQ2 was notably overrepresented in atypical patients compared to typical ones (pc= 0.001). The MICA-A5.1 allele was increased in atypical CD patients compared to those with typical forms (pc= 0.0006). Finally, we found that the increased frequency of MICA-A5.1 in the atypical group was independent of the linkage disequilibrium with B8/DR3/DQ2 haplotype (p= 0.02).


CONCLUSIONS
The elevated prevalence of CD in Saharawi seems to be related to the high frequency of HLA-DQ2 in this population. However, the development of atypical or typical forms of the disease may be due to a gene or genes located in the class I side of the haplotype B8/DR3/DQ2, especially MICA. This appears not to be implicated in the susceptibility to CD but may play an important role in the development of the different forms of the disease.
López-Vázquez
Antonio
A
Department of Immunology, Hospital Universitario Central de Asturias, Oviedo, Spain.
Fuentes
Dolores
D
Rodrigo
Luis
L
González
Segundo
S
Moreno
María
M
Fernández
Eloy
E
Martínez-Borra
Jesús
J
López-Larrea
Carlos
C
D000328:Adult; D000352:Africa, Northern; D002446:Celiac Disease / Q000235:genetics*; D002648:Child; D005260:Female; D005805:Genes, MHC Class I / Q000235:genetics*; D015395:Histocompatibility Antigens Class I / Q000235:genetics; D006650:Histocompatibility Testing; D006801:Humans; D008297:Male; D012036:Refugees
D015395:Histocompatibility Antigens Class I; C099187:MHC class I-related chain A