Abstract: Objective To study the role of abmormal comeetration, of DNase in the development, of SLE.Methods The coneentration of DNase was measured by single radial enzynme diffusion method in the sera of 63 SLE patients.Results The coneentration of DNase in the patients was significantly lower tha in healthy indivduals, signifieantly lower patients at active slage than in remission, and Iowest in patients with lupus nephrilis.The deerease of serum DNase was negatively eorlreIated with the increase of serum DNA. The level of DNase was Hegatively correlated with ANA and ESR.positively correlated with C3.C4.and negalively correlated with the severitv of the disease Conclusion The above data suggest that the decrease of serum DNase make, the persistence of DNA in the blood eireulation which combines with anti DNA antibody to form immune complex resulting in autoimmune lesions.The deereaset of serum DNase an important role in the pathogenesis SLE.

Key words: Lupus erythematosus, systemic, Deoxyribonueleases