CTLA-4 gene polymorphism is associated with predisposition to coeliac disease.
BACKGROUND
Susceptibility to coeliac disease is strongly associated with particular HLA class II alleles. However, non-HLA genetic factors are likely to be required for the development of the disease. Among candidate genes is the CTLA-4 (cytotoxic T lymphocyte associated) gene located on chromosome 2q33 in humans, which encodes a cell surface molecule providing a negative signal for T cell activation.


OBJECTIVE
To investigate CTLA-4 exon 1 polymorphism (position 49 A/G) in patients with coeliac disease.


METHODS
101 patients with coeliac disease and 130 healthy controls.


METHODS
Allele specific hybridisation and restriction enzyme digestion of polymerase chain reaction amplified genomic DNA.


RESULTS
The A allele of the CTLA-4 position 49 polymorphism was found on 82.2% of chromosomes in patients with coeliac disease compared with 65.8% in controls (p < 0.0001), mostly in the homozygous form (68.3% in patients versus 47.7% in controls; odds ratio (OR) 2.36, 95% confidence interval (CI) 1.37 to 4.06, p = 0.002). Four patients only had the G/G genotype compared with 21 controls (OR 0.21, CI 10.07 to 0.64, p = 0.002). These differences were maintained when subjects were stratified according to the HLA class II phenotype, in particular when patients and controls were matched for the presence of the predisposing HLA DQB1*02 (DQ2) allele or HLA-DQA1*0501/DQB1*02 heterodimer.


CONCLUSIONS
The CTLA-4 gene polymorphism is a non-HLA determinant that predisposes to coeliac disease. Whether it directly contributes to disease susceptibility or represents a marker for a locus in linkage disequilibrium with CTLA-4 needs further investigation.
Djilali-Saiah
I
I
INSERM U25, Hôpital Necker-Enfants Malades, Paris, France.
Schmitz
J
J
Harfouch-Hammoud
E
E
Mougenot
J F
JF
Bach
J F
JF
Caillat-Zucman
S
S
D000069594:Abatacept; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000235:genetics*; D060908:CTLA-4 Antigen; D002446:Celiac Disease / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D005802:Genes, MHC Class II / Q000235:genetics; D020022:Genetic Predisposition to Disease; D015803:HLA-DR3 Antigen / Q000235:genetics; D006801:Humans; D018796:Immunoconjugates; D008297:Male; D011110:Polymorphism, Genetic
D015703:Antigens, CD; D000943:Antigens, Differentiation; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; D015803:HLA-DR3 Antigen; D018796:Immunoconjugates; D000069594:Abatacept