Anti-DNase I antibodies in systemic lupus erythematosus: diagnostic value and share in the enzyme inhibition.

Diagnostic accuracy of anti-DNase I antibodies measurement in a differentiation between SLE and other autoimmune rheumatic diseases was evaluated. The share of anti-DNase I and actin in the DNase I activity decrease in SLE was established. Serum samples were obtained from 54 patients with verified SLE, 52 control patients with other autoimmune rheumatic diseases, and 44 healthy persons. Anti-DNase I concentrations were measured by ELISA. Free and actin inhibited DNase I activities were evaluated in the fresh serum samples. The appraisal of antibodies and actin effects on DNase I activity was made using multiple regression. Anti-DNase I antibodies were positive in 35 SLE and 8 control patients, without significant difference between the mean antibody concentrations. Sensitivity of this test was 64.81 %, and specificity-84.62 %. Mean free DNase I activity in SLE was somewhat lower than in the control group as a result of augmented frequency of extremely low enzyme activities. On the contrary, after the exclusion of the latter cases we have revealed elevated mean free DNase I activity in the other SLE patients comparing to the similar control subgroup. Unlike the controls, low serum DNase I activity in SLE arose not only from actin and antibody action, but also, in half of the cases, from unidentified factor, related to active SLE. The accuracy of the anti-DNase I antibodies measurement is approximate to the present reference standard of SLE diagnostics. We first demonstrated that neither antibodies nor actin caused DNase I activity decrease in SLE.

Emulsive polymerization as a method of enzyme modification preserving biological properties of nanostructures.

The proposed method of emulsive polymerization provides the possibility of modifying and obtaining insoluble forms of superoxide dismutase (SOD), glutathione reductase, and streptolysin-O preserving nanoobjects (conformationally active centers and antigenic determinants) in their native states. Apart from enzymatic and immunological properties, the samples acquired some new features: resistance to high temperature, resistance to 3 M KCNS solution and buffer solutions with high concentration of hydrogen ions, and resistance to preserving solutions. Magnetic properties provide the possibility of simplifying enzyme-linked immunosorbent and immunofluorescence assays. In addition, sensitivity of these assays was by an order of magnitude higher and the specificity fully preserved. Taking all the facts into account, we prepared agents for long-term and repeated use. Due to preserved enzymatic properties, insoluble forms of SOD and glutathione reductase can be considered as a tool for correction of peroxide-antioxidant balance and associated immunological abnormalities.