Expression of circulating Semaphorin3A and its association with inflammation and bone destruction in rheumatoid arthritis

To determine the expression of Semaphorin3A (Sema3A) in rheumatoid arthritis (RA) patients, and analyze the correlation between serum Sema3A and the pathogenesis of RA. The concentration of serum Sema3A and its mRNA expression level were detected in RA patients. The association of serum Sema3A level with clinical and laboratory features of RA were analyzed. Serum Sema3A of 130 RA patients (15.89 ± 8.58 ng/ml) was significantly higher than that of 150 HC (6.96 ± 2.62 ng/ml) and 215 patients with other rheumatic diseases ( P < 0.05). Consistent with the serum level, the Sema3A mRNA level was also higher in RA patients’ PBMC than that in HC (1.8-fold increase, P < 0.01). The serum level of Sema3A was correlated with platelet counts ( r = 0.229), ESR ( r = 0.172), RF ( r = 0.230), IgM ( r = 0.254) and Sharp score ( r = 0.254), and bone mineral density (BMD) of lumbar spine ( r = 0.263). Serum Sema3A was also fundamentally higher in AKA-, APF-, anti-CCP-positive groups compared with negative groups ( P < 0.05). The ROC curve showed that the optimum diagnostic cutoff value for Sema3A was 10.881 ng/ml. RF level and antibodies (anti-CCP, APF, AKA, and GPI) positive rates were significantly higher in Sema3A positive group. Sharp score was also higher, although without significance. The expression of Sema3A is significantly elevated in RA patients. The level of serum Sema3A is positively correlated with inflammatory factors (including ESR, IgM, and RF) and is associated with auto-antibody production and bone destruction.