Association of CTLA4 gene polymorphism in Iranian patients with ankylosing spondylitis.
BACKGROUND
Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is a costimulatory molecule expressed by activated T cells. This study was performed to investigate the allele and genotype frequencies of CTLA4 gene polymorphisms in Iranian patients with ankylosing spondylitis (AS).


METHODS
One hundred and fifty-seven patients with AS and 103 controls were included in this study. Polymorphisms of CTLA4 gene at positions +49 (in exon 1), -318, and -1,147 (in the promoter region) were studied on the genomic DNA using PCR restriction fragment-length polymorphism method.


RESULTS
The frequencies of the T allele at position -1147 in the patients with AS was significantly increased in comparison with the control group (11% vs. 5%, P = 0.004); whereas the frequencies of C allele at the same position were significantly decreased in the patient group (89% vs. 95%, P = 0.004). Comparison of genotype frequencies at this position showed that the frequency of CT genotype in comparison with other genotypes was overrepresented in the patient group (20% vs. 8%, P = 0.012), while the CC genotype in comparison with other genotypes was decreased (79% vs. 91%, P = 0.012). There was no significant difference on frequencies of genotypes at the positions -318 and +49.


CONCLUSIONS
This study could suggest an association between specific allele in the promoter region of CTLA4 gene and AS disease.
Azizi
Esfandiar
E
Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Massoud
Ahmad
A
Amirzargar
Ali Akbar
AA
Mahmoudi
Mahdi
M
Soleimanifar
Narjes
N
Rezaei
Nima
N
Jamshidi
Ahmad Reza
AR
Nikbin
Behrouz
B
Nicknam
Mohammad Hossein
MH
D000293:Adolescent; D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000235:genetics* / Q000276:immunology; D060908:CTLA-4 Antigen; D004252:DNA Mutational Analysis; D005091:Exons / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007492:Iran; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic / Q000235:genetics*; D013167:Spondylitis, Ankylosing / Q000235:genetics* / Q000276:immunology*
D015703:Antigens, CD; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human