The present study was carried out on 30 patients with systemic lupus erythematosus (SLE) and ten apparently healthy individuals as a control group.Systemic lupus erythematosus activity index (SLEDAI) was applied to all patients. Anti-double stranded DNA antibodies (Anti-dsDNA Abs.) , interleukin-18 (IL-18) and soluble CD95 (Apo-1/Fas) were determined in the sera of all studied subjects. The mean ±SD SLEDAI in all patients was 15.25± 6.76 . The anti-dsDNA antibodies was positive in all studied patients (mean ± SD 264.36 ± 114.85 IU/ml). Serum IL-18 showed significant elevation in SLE patients as compared to the control group (Mean ±SD 246.13± 114.32I U/ml vs. 45.5 ± 7.32 IU/ml ; p < 0.001). Serum Soluble CD95 (sCD95)showed significant increase in all SLE patients as compared to the control group (Mean±SD 648±116.96 pg/ml vs. 270±50.24 pg/ml ;p < 0.001). Serum sCD95 also showed significant rise in SLE patients with moderate activity as compared to those with mild activity (Mean ± SD 629.16± 72.54 pg/ml vs. 535 ±35.97 pg/ml; p<0.05). The serum level of sCD95 in SLE cases with severe activity showed significant increase when compared to those with moderate activity ( Mean±SD 797.5 ± 41.66 pg/ml vs. 629.16 ± 72.54 pg/ml ; p <0.001).
Anti-dsDNA antibodies showed significant positive correlation with SLEDAI (r=0.772;p<0.01). IL-18 also showed a significant positive correlation with the SLEDAI (r=0.670 ;p<0.01).
Soluble CD95 showed significant positive correlation with SLDAI (r=0.865 ; p<0.01), with anti-dsDNA antibodies (r=0.775 ;p<0.01) and with IL-18 (r =0.722 ; p<0.01). From these results it was concluded that serum sCD95 is increased in patients with systemic lupus erythematosus and it is correlated with anti-dsDNA antibodies , with IL- 18 and with the disease activity, so it can be useful marker of disease activity for proper management and follow up of SLE patients.