Suppressive effect of vitamin K2 against mitogen-activated peripheral blood mononuclear cells of rheumatoid arthritis patients

Objective: To investigate the immunosuppressive effect of vitamin K2 against mitogen-activated peripheral blood mononuclear cells (PBMCs) of rheumatoid arthritis (RA) patients. Materials and methods: Concanavalin A-stimulated PBMC culture procedure was used to evaluate the pharmacodynamics of vitamin K2 in vitro. Methotrexate was set up as the positive control. The proliferation of PBMCs was detected by MTT assay. Relationship between IC50 values of drugs on PBMC proliferation and patient-related factors including laboratory data was analyzed by nonparametric Spearman correlation test. Results: Vitamin K2 inhibited the proliferation of mitogen-activated PBMCs of RA patients with an IC50 value of 3,288.47 +/- 4,910.02 ng/mL (mean +/- SD). There was a significant correlation between IC50 values of vitamin K2 and patient-related factors of RA patients (p < 0.05), such as C-reactive protein (CRP), rheumatoid factor, anti-cyclic citrullinated peptide antibody (ACPA), matrix metalloproteinase-3, Pre-DAS-28 (CRP), and Delta DAS-28 (CRP). It would be possible to predict the pharmacodynamics of vitamin K2 in RA patients according to the above factors. Methotrexate inhibited the proliferation of mitogen-activated PBMCs of RA patients with a IC50 value of 22.83 +/- 12.47 ng/mL (mean +/- SD). IC50 values of methotrexate only showed significant correlation with ACPA (p = 0.0158, r = 0.6905), which suggests that ACPA might be a suitable predictor of the pharmacodynamics of methotrexate. Conclusion: The above information suggests that vitamin K2 could provide a benefit for the treatment of RA patients via its immunosuppressive function.