Effects of Tumor Necrosis Factor Inhibitor on Serum Level of HLA-B27 and PDCD-1 in Patients with Ankylosing Spondylitis

The aim of this study was to evaluate the effect of tumor necrosis factor-alpha (TNF-α) inhibitor-infliximab on ankylosing spondylitis (AS) patients and detect the serum level of HLA-B27 and PDCD-1 before and after TNF inhibitor treatment. 138 patients at active stage of AS were treated with infliximab; serum was collected before and after TNF-α inhibitor treatment for analysis. Reverse transcription-polymerase chain reaction (RT-PCR), flow cytometry, and enzyme-linked immuno sorbent assay were applied to detect the levels of HLA-B27 and PDCD-1 at different time points, which were used for statistical analysis with clinical data including two AS indicators (erythrocyte sedimentation rate—ESR and C-reactive protein—CRP). After the treatment for 6 weeks, RT-PCR showed that the gene expressions of HLA-B27 and PDCD-1 were significantly downregulated compared with baseline before infliximab treatment (P < 0.05); flow cytometry showed that the HLA-B27 and PDCD-1 double-labeled cells were significantly downregulated (P < 0.05). After 2, 6, or 10 weeks of infliximab treatment, the levels of ESR, CRP, serum HLA-B27, and PDCD-1 of the AS patients were all significantly lower than the baseline levels (P < 0.05), and the serum HLA-B27 and PDCD-1 levels were all significantly correlated with ESR (P < 0.05). Infliximab, an anti-TNF-α inhibitor, decreases significantly not only ESR and CRP, but also the serum levels of HLA-B27 and PDCD-1 in patients with AS. HLA-B27 and PDCD-1 are involved in the pathogenesis, and disease activities of AS. HLA-B27 and PDCD-1 are potentially the useful markers of AS activity and useful parameters to evaluate the effectiveness of anti-TNF-α inhibitor in treating AS.