The expression of molecular chaperone HSP90 and IL-6 in patients with systemic lupus erythematosus

To explore the expression and clinical significance of molecular chaperone heat shock protein 90 (HSP90) in peripheral blood mononuclear cells (PBMC) and plasma level of interleukin-6 (IL-6) in patients with systemic lupus erythematosus (SLE), HSP90 was detected in PBMC by Western blot assay and the plasma level of IL-6 was measured by ELISA in 38 SLE patients and 20 normal controls. The correlation analysis was performed between the SLE disease activity index (SLE-DAI) and the expression of HSP90 and IL-6. The results showed that there was increased expression of HSP90 in the SLE patients. The active SLE group exhibited higher HSP90 levels (0.82+/-0.10) than the inactive SLE group (0.54+/-0.09) (P<0.01). The expression of HSP90 in normal control group (0.37+/-0.11) showed significant statistical difference as compared to both the inactive and active SLE groups (P<0.01, P<0.01, respectively). The plasma level of IL-6 exhibited a significant increase in both the inactive and active SLE groups (28.99+/-1.74 pg/mL, 44.58+/-9.15 pg/mL, respectively) compared with normal control group (P<0.01, P<0.01, respectively). The expression of HSP90 and IL-6 in SLE patients showed significant positive correlation with SLEDAI scoring (r=0.80, P<0.01: r= 0.74, P<0.01, respectively). In addition, there was a positive correlation between the level of IL-6 and HSP90 in SLE patients (r=0.86, P<0.01). The increased expression of molecular chaperone HSP90 and IL-6 may play an important role in the pathogenesis of SLE by regulating autoimmunity.