[Expression of interferon and its correlation with clinical features in idiopathic inflammatory myopathies].

OBJECTIVE

To detect the expression levels of interferons IFNα, IFNβ and IFNγ in the peripheral blood and muscle of patients with idiopathic inflammatory myopathies (IIM) so as to analyze their relationships with organ manifestations.

METHODS

The serum levels of IFNα, IFNβ, IFNγ and anti-Jo-1antibody were measured with ELISA (enzyme-linked immunosorbent assay). And the method of SYBR green dye based real-time quantitative PCR (polymerase chain reaction) was used to compare the expression levels of IFNα, IFNβ, interferon α receptor 1 (IFNαR1), signal transducer and activator of transcription 1 (STAT1) in the IIM patients and normal controls.

RESULTS

The serum levels of IFNα (50.2 ± 21.0) ng/L and IFNβ (10.7 ± 5.4) ng/L in IIM patients were significantly higher than those in normal controls (18.6 ± 3.6) ng/L, (3.9 ± 0.8) ng/L (P < 0.01). And the serum levels of IFNα (55.7 ± 21.9) ng/L and IFNβ (11.3 ± 2.3) ng/L in DM patients were significantly higher than those in PM patients (26.1 ± 8.2) ng/L, (6.2 ± 3.5) ng/L (P < 0.05). The serum levels of IFNα and IFNβ correlated with the presence of skin rash (P < 0.05). And their serum concentrations correlated positively with erythrocyte sedimentation rate (r = 0.442, P = 0.000; r = 0.562, P = 0.000) and C-reactive protein (r = 0.348, P = 0.004; r = 0.432, P = 0.005)respectively. The serum levels of IFNα and IFNβ decreased significantly after treatment in 12 PM/DM (polymyositis/dermatomyositis) patients (P < 0.01). The mRNA expression levels of IFNα, IFNβ, IFNαR1 and STAT1 in PM/DM patients were higher than those in normal controls (P < 0.05).

CONCLUSION

The expression levels of IFNα and IFNβ in PM/DM patients are significantly higher than those in normal controls. And the increments had correlations with disease activity and severity. STAT1 has been implicated in signal transduction of IFNα and IFNβ in the muscles of PM/DM patients.