[Peripheral blood mRNA and interferon gene expression in systemic lupus erythematosus]

Abstract

Objective: To investigate the expression levels of interferon (IFN)-alpha, -beta, -omega and -gamma genes and proteins in the peripheral blood of patients with systemic lupus erythematosus (SLE), and to evaluate any possible connections between these expression levels with clinical features.

Methods: 144 SLE patients, 27 non-SLE patients with rheumatisms and 59 normal controls were recruited for the research, and all subjects were drawn blood to isolate plasma and elute total RNA. SYBR Green Dye based real-time quantitative PCR method was used to compare the expression levels of 4 IFNs in patients with SLE and those in the controls. The significance for the correlation of these expression levels and disease activity and specificity was studied.

Results: (1) mRNA expression levels of all 4 IFNs in SLE patients were remarkably lower than those observed in normal controls (P < 0.01 in all); IFN-alpha expression levels in SLE patients were increased than those observed in non-SLE group (P < 0.01). (2) The expression levels of all 4 IFNs in active SLE patients were similar to those observed in inactive SLE patients (P > 0.05 in all), and expression levels of all 4 IFNs in patients with SLE were not correlated with involvements of kidney, lung, brain, blood. (3) IFN score in SLE patients was remarkably lower than that observed in normal controls (P < 0.01). (4) The expression levels of all 4 IFNs in both SLE patients and normal controls were positively correlated with each other (P < 0.01 in all). (5) Protein levels of IFN-alpha, IFN-beta and IFN-omega in patients with SLE were similar to those observed in normal group (P > 0.05 in all), protein level of IFN-alpha in active SLE group was apparently elevated than in inactive SLE group (P < 0.01), and protein level of IFN-gamma has a trend to increase in SLE group than in normal group.

Conclusions: Decreased expression levels of IFN-alpha, -beta, -omega and -gamma have implicated significance in the determination of SLE disease specificity, of which IFN-alpha is the best. Lower expression level of IFN score has also significance in the determination of SLE disease specificity. Higher protein level of IFN-alpha is helpful to judging SLE disease activity.