Replication study of STAT4 rs7574865 G/T polymorphism and risk of rheumatoid arthritis in a Chinese population.

AIM: Rheumatoid arthritis (RA) and ankylosing spondylitis (AS) are common systemic autoimmune diseases with genetic and environmental predisposing factors. Signal transducer and activator of transcription 4 (STAT4) transmits signals induced by interleukin-12, interleukin-23 and interferon-γ, which are key cytokines and play important roles in the development of autoimmune diseases. Previous studies confirmed the STAT4 rs7574865 G/T locus to be associated with RA. Thus we conducted a replication study to investigate STAT4 rs7574865 G/T polymorphism and RA/AS susceptibility in a Chinese population.
METHODS: We studied STAT4 rs7574865 G/T gene polymorphism in 520 patients with RA, 100 AS patients and 520 controls in a Chinese population. Genotyping was done using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).
RESULTS: When the STAT4 rs7574865 GG homozygote genotype was used as the reference group, the GT or GT/TT genotypes were associated with the risk for RA. After stratification analyses, a significantly increased risk for RA associated with the STAT4 rs7574865 GT genotype was evident among the rheumatoid factor (RF)-positive patients, patients with higher erythrocyte sedimentation rate (ESR) level and patients with higher RA disease activity score (DAS28) compared with the STAT4 rs7574865 GG genotype. A significantly increased risk for RA associated with the STAT4 rs7574865 TT genotype was evident among older patients and RF-negative patients compared with the STAT4 rs7574865 GG genotype. STAT4 rs7574865 G/T was not associated with susceptibility to AS.
CONCLUSION: This replication study confirmed that STAT4 rs7574865 G/T polymorphism was associated with the risk of RA. CONDENSED ABSTRACT: STAT4 polymorphisms are associated with rheumatoid arthritis risk.