The gene encoding cytotoxic T lymphocyte associated antigen-4 (CTLA-4) has been reported to be associated with rheumatoid arthritis (RA) in several ethnic populations. The aim of this work is to assess the association of this polymorphism with the susceptibility, activity and functional disability of RA in Egyptian subjects.
This study included 112 unrelated RA Egyptian patients who were compared to 122 healthy controls from the same locality. For all subjects, DNA was genotyped for CTLA-4 +49 A>G (rs231775) polymorphism using the PCR-RFLP technique. Antibodies to cyclic citrullinated peptides (anti-CCP) were measured by enzyme-linked immunosorbent assay (ELISA).
The frequency of the CTLA-4 G allele was significantly higher among cases compared to controls (37.1% vs. 23.4%, OR=1.93; 95% CI=1.29-2.89, p=0.002). Also, the frequency of CTLA-4 +49 G allele carriage (AG+GG genotypes) was significantly higher among cases with RA compared to controls (61.6% vs. 41.8%, OR=2.23, 95% CI=1.32-3.77, p=0.003). Logistic regression analysis showed that cases positive to the G allele (GA+GG genotypes) had less frequency of rheumatoid deformities and also a lower DAS28-CRP score, yet with a higher visual analogue scale (VAS) i.e. more functional disability than other cases.
CTLA-4 +49 G allele carriage was associated with increased susceptibility and functional disability of RA in Egyptian patients.