Associations of expression of nuclear factor kappa B and apoptosis with B cell in patients with rheumatoid arthritis

Abstract

Objective To investigate the relations between the expression of nuclear factor kappa B of B cells in the peripheral blood(PB) and the apoptosis with B cell in patients with rheumatoid arthritis (RA). Methods B cells in the PB of 48 RA and 30 healthy individuals were isolated by MACS and Western blot was used to detect the expression of NF-κBp50, NF-κBp65, IκBα, phosphor-NF-κBp65 (P-NF-κBp65), phosphor- IκBα(P-IκBα), apoptosis related proteins Caspase-3 and Bcl-2.The levels of interleukin(IL)-17, IL-6, tumor necrosis factor-α(TNF-α)in patients with RA were measured by enzyme-linked immunosorbent assay(ELISA). The proportions of apoptosis of B cells in the PB of patients with RA and healthy controls were determined by flow cytometry.T-test and Pearson correlation analysis were used to analyze the data. Results The expression of P-NF-κBp65 and P-IκBα of B cells in the PB of patients with RA was significantly higher than that of control group[(30.5±10.1)vs.(13.4±4.8); (25.6±9.2)vs.(16.5±5.8)], the difference was statistically significant(t=5.071, t=4.643, both P 0.05). The expression of P-NF-κBp65 and Bcl-2 were positively correlated in patients with RA (r=0.311, P<0.05). There was a negative correlation between the level of P-NF-κBp65 and the rate of apoptosis of B cells in the patients with RA(r=-0.472, P<0.05). The expression of P-IκBα has no correlation with the rate of apoptosis of B cells in the patients with RA (r=-0.075, P=0.104). Conclusion The expression of P-NF-κBp65 and P-IκBα dramatically increased in B cell of PB from RA patients and the expression of P-NF-κBp65 is closely related Bcl2 and the rate of B cell apoptosis, indicating that the activation of NF-κB signal pathway could regulate Bcl-2 expression which inhibit B cell apoptosis in the patients with RA. Key words: Rheumatoid arthritis; B cell; Nuclear factor kappa B; Bcl-2; Cell apoptosis