Validation of candidate genes expression in ACPA+ RA patients
To validate the differential expression levels of candidate genes in ACPA+ and ACPA- RA patients, the expression levels of CXCL2 and CXCL7 were measured using real time PCR. CXCL2 levels were higher in ACPA+ RA patients (n=40) than in ACPA- RA patients (n=40) and healthy controls (n=40) (Fig. 2A), confirming that CXCL2 was differentially expressed in ACPA+ RA patients and ACPA- RA patients. However, there was no significant difference in CXCL7 expression between ACPA+ RA patients and ACPA- RA patients.