IL-17 induces autoantibody overproduction and peripheral blood mononuclear cell overexpression of IL-6 in lupus nephritis patients / 中华医学杂志(英文版)

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the role of IL-17 in the overproduction of autoantibodies and IL-6 overexpression by peripheral blood mononuclear cells (PBMC) of lupus nephritis (LN) patients.</p><p><b>METHODS</b>Fifteen consecutively hospitalized LN patients were selected as subjects and 15 healthy adults as normal controls. PBMC were obtained by Ficoll density gradient centrifugation. IgG, anti-dsDNA antibody and IL-6 protein levels were assessed using enzyme-linked immunosorbent assays (ELISA) on the supernatant of cultured PBMC of LN patients or normal controls. IL-6 mRNA levels in PBMC were measured using reverse transcription-polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>In medium culture, IgG, anti-dsDNA and IL-6 protein levels of the supernatant of PBMC from LN patients were significantly higher than those from normal controls (1492.1 +/- 73.2 ng/ml vs 636.7 +/- 51.9 ng/ml for IgG, 306.6 +/- 53.7 IU/ml vs 95.8 +/- 11.6 IU/ml for anti-dsDNA and 50.92 +/- 15.92 ng/ml vs 1.77 +/- 0.73 ng/ml for IL-6, all P < 0.001). In LN patients, IgG, anti-dsDNA and IL-6 protein levels were higher in the supernatants of PBMC in the IL-17-stimulated culture than the medium culture, but in normal controls, only the IL-6 protein levels were significantly higher. The increase in IgG, anti-dsDNA and IL-6 protein levels induced by IL-17 was dose-dependent and could be completely blocked by IL-17 monoclonal antibody mIgG(28) and partially blocked by dexamethasone. Similarly, IL-6 mRNA overexpression of PBMC in LN patients or normal controls induced by IL-17 was both dose- and time-dependent. During medium culture, IL-6 mRNA levels in LN patients were significantly higher than those in normal controls (1.80 +/- 0.11 vs 0.36 +/- 0.07). During stimulation with IL-17, IL-6 mRNA levels in LN patients were higher than those in normal controls (3.21 +/- 0.24 vs 1.30 +/- 0.14, P < 0.05) and also significantly higher when comparing the stimulated culture with the medium culture either in LN patients or normal control.</p><p><b>CONCLUSIONS</b>IL-17 may play an important role in the pathogenesis of LN through the induction of IgG, anti-dsDNA overproduction and IL-6 overexpression of PBMC in LN patients.</p>