[The expression and clinical significance of proprotein convertase subtilisin kexin 9 in rheumatoid arthritis].

Objective: To assess the expression and significance of proprotein convertase subtilisin kexin 9 (PCSK9) in patients with rheumatoid arthritis (RA). Methods: Sixty-five RA patients and forty-seven healthy controls were recruited in this study. The body mass index (BMI) and serum total cholesterol(TC), triglyceride(TG), high density lipoprotein(HDL), lipoprotein a, low density lipoprotein(LDL), very low density lipoprotein(VLDL), apolipoprotein A(ApoA), apolipoprotein B(ApoB) and the ratio of LDL-C/HDL-C were tested. Other parameters included disease activity score 28(DAS28), rheumatoid factor (RF), anti-cyclic citrullinated peptide (CCP) antibody, erythrocyte sedimentation rate (ESR), c-reactive protein (CRP). Serum PCSK9 level was measured by ELISA and compared between RA patients and healthy controls. Results: (1) The serum PCSK9 levels in RA patients were higher than those in healthy controls[(409.36±223.52) μg/L vs (292.19±109.79) μg/L, P<0.05]. (2) Compared with subgroup of moderate and low active disease and patients in remission, PCSK9 was significantly higher in patients with highly active disease (P<0.05). (3) The serum PCSK9 levels were positively correlated with RF, TC, TG, LDL, very low density lipoprotein (VLDL), ApoB, with r values as 0.303, 0.490, 0.320, 0.451, 0.319, 0.463, respectively (P<0.05). (4) Multiple stepwise regression analysis showed that DAS28, RF, TC and LDL-C/HDL-C were relevant factors for PCSK9 in RA patients. Conclusions: The serum PCSK9 level is elevated in RA patients, which is related to RF, disease activity, TC, TG, LDL, VLDL, ApoB. This suggests that PCSK9 is potentially linked to inflammatory reaction and lipid metabolism in rheumatoid arthritis.