Background: Individual studies have reported different results regarding the association of HLA alleles with RA in Chinese populations. This study was performed to systematically summarize results on the association of HLA-DRB1 with rheumatoid arthritis (RA) in China.
Methods: We examined the case-control studies concerned about the relationship between HLA-DRB1 and RA and differences of clinical and laboratory parameters between the HLA-DR4 (DR4)+ and DR4- in RA patients in Chinese populations. Odds ratios (ORs) and weighted mean difference (WMD) with corresponding 95% confidence intervals (CI) was used to describe the relationship.
Results: 22 studies with 1690 cases and 1793 controls were included. Chinese populations with RA had significantly higher frequencies of HLA-DRB1*04, *0401, *0404, *0405 and *0410 than controls (ORDRB1*04 =4.19, 95% CI =3.44-5.11, p<0.00001; ORDRB1*0401 =2.53, 95% CI =1.54-4.16, p=0.0003; ORDRB1*0404 =2.28, 95% CI =1.28-4.06, p=0.005; ORDRB1*0405=3.71, 95% CI =2.52-5.45, p<0.00001; ORDRB1*0410 =2.99, 95% CI =1.25-7.14, p=0.01 respectively). As to laboratory parameters, Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), Rheumatoid factor (RF), Anti-cyclic citrullinated peptide antibodies (Anti-CCP ) in patients with DR4+ were higher than patients with DR4- (WMD=0.26, 95% CI =0.15-0.37, p<0.00001; WMD = 0.26, 95% CI =0.12-0.41, p=0.0005; WMD = 0.44, 95% CI =0.23-0.65, p<0.00001; WMD = 0.58, 95% CI =0.24-0.91, p=0.0007 respectively). As to clinical features, there was no difference in duration of morning stiffness, number of swollen joints, number of joint tenderness, X-ray phases and joint function between the DR4+ and DR4- in RA patients.
Conclusions: It was found that HLA-DRB1*04, *0401, *0404, *0405 and *0410 are risk factors for RA in Chinese populations. ESR, CRP, RF, Anti-CCP are different between the DR4+ and DR4- in RA patients in Chinese populations, while there's no difference for indexes of clinical features.