Annotation The aim of the research is to determine the levels and frequency of antibodies popularity to cyclic citrullinated peptide (APCCP), rheumatoid factor (RF), anti-Sa antibodies and antibodies to heterogeneous nuclear ribonucleoprotein K (anti-gRNP K) in rheumatoid arthritis (RA) and to compare their diagnostic characteristics, and also to determine sensitivity and specificity of anti-Sa antibodies, anti-hRNP K in seronegative RA. Material and methods. The study included 270 patients with RA and 50 healthy individuals. The levels of ACCP, anti-Sa, anti-hRNP K were assessed in blood serum samples from patients by enzyme-linked immunosorbent assay using commercial test systems. RF levels were assessed by kinetic nephelometry on automatic analyzer. Results. The levels and popularity frequency of the studied antibodies in patients with RА were significantly higher than in healthy individuals (p <0.05). Tests based on ADCP detection had the highest indices of sensitivity and specificity for RA diagnosis; sensitivity - 78.01%, specificity - 100.00%, and RF - 70.64%, specificity 96.97%. In case of serogegative APCCP and RA RF, diagnostic sensitivity of anti-Sa antibodies determination was 50.00%, specificity was 96.77%, sensitivity of anti-hRNP K antibodies determination was 55.56%, and specificity was 100.00%. Conclusion. Considering high specificity of tests for anti-Sa and anti-hRNP K antibodies in seronegative RA, they can be considered as additional confirmatory diagnostic tests.

Catalytic properties of immunoglobulins are widely studied within recent years. It was found that nuclease activity of immunoglobulins is increased in systemic autoimmune diseases. Given some pathogenetic features of rheumatoid arthritis and reactive arthritis, it is appropriate to clarify the nature of nuclease activity in these diseases. Determination of DNAse activity of immunoglobulins with different DNA substrates, and search for specific substrates for distinct clinical entities could serve these purposes. The aim of present work is to determine DNase activity of the polyclonal class G immunoglobulins in rheumatoid and reactive arthritis using various methods.Different methods are used to evaluate nuclease activity. In this paper we present newly developed and modified techniques for determination of DNAse activity of polyclonal IgGs. Particular attention was paid to the electrophoretic method of DNase activity assessment. Polyclonal IgG isolated from blood serum of patients with rheumatoid arthritis and reactive arthritis were used for assays. In this study, we demonstrated the presence of an inhomogeneous DNase activity of immunoglobulins in relation to different substrates.Along with calf thymus DNA, we used bacterial plasmid DNA and PCR products based on bacterial gene sequences. Levels of DNase activity by rivanol clot method with calf thymus DNA as substrate proved to be higher in patients with rheumatoid arthritis than the control values (p < 0.01). DNase abzyme activity in patients with rheumatoid arthritis was elevated, as compared to the patients with reactive arthritis (p < 0.01).When examining ability of the IgG to hydrolyze procaryotic DNA (bacterial plasmid DNA and PCR products, based on bacterial genes), we obtained heterogeneous results. Different Ig samples showed varying degrees of DNA hydrolysis. Abzyme hydrolysis of DNA substrates longer than 700 bp was more pronounced, as compared to short DNA substrates (100 base pairs).Conclusions: 1) antibodies having deoxyribonucleic activity are present in serum of patients with rheumatoid arthritis, reactive arthritis; 2)DNase abzymes exhibit heterogeneous ability to hydrolyze various DNA substrates; 3) Abzyme-medicted hydrolysis of DNA substrates longer than 700 base pairs is more pronounced, as compared to a short DNA substrates (100 bp) length.

Abstract. A group of 266 patients with spondyloarthritidis and 69 healthy persons were included in our study. IgG preparations were isolated from blood sera by a combined rivanol/affine chromatography technique. Homogeneity of IgGs was tested by means of SDS-PAGE. Serum samples from patients and healthy persons, and IgG subclasses 1, 2 and 4 were tested for DNAse activity. A method of DNAse activity measurement was based on rivanol capacity to form a clot with DNA. We have found highly significant differences between the levels of DNAse activity associated with IgG preparations and in blood sera from patients with spondyloarthritidis, and healthy donors (p < 0,0001). DNAse activity of IgG and sera in patients with psoriatic arthritis was higher than in patients with reactive arthritis and ankylosing spondylitis (p < 0,0001). Multiple correlations were revealed between DNAse activity of IgG, blood serum, clinical signs of psoriatic arthritis, reactive arthritis, ankylosing spondylitis, and laboratory findings. We have developed novel tests for differential diagnosis between various disorders, e.g., spondyloarthritidis, based on IgG and serum-associated DNAse activity, corresponding to the criteris of useful and very useful diagnostic tests in rheumatology.

Antibodies executing catalytic activity are referred to as antibody enzymes or short "abzymes" and may have diagnostic relevance. Abzymes with deoxyribonuclease (DNase) activity have been demonstrated in patients with autoimmune and infectious diseases. Despite several reports on the occurrence of DNase abzymes in systemic autoimmune rheumatic diseases, conclusive data about DNase activity of antibodies in patients with spondyloarthritides (SpAs) are lacking. In recent cross-sectional studies evaluating levels of IgG DNase activity in patients with psoriatic arthritis (PsA), reactive arthritis (ReA), and ankylosing spondylitis (AS), DNase activity of IgG has been assessed by the rivanol clot method and confirmed by agarose gel electrophoresis. Remarkably, levels of IgG DNase activity were significantly higher in sera of SpA patients than those in control subjects. In patients with PsA, ReA, and AS, a positive correlation of DNase IgG activity with synovitis, disease activity, and stage of spondylitis was observed, respectively. Given the involvement of autoimmune reactions in cytolysis and connective tissue degradation in PsA, ReA, and to a lesser extent in AS, abzymes might have an impact on the pathophysiology of SpAs. Detection of IgG DNase activity in patients suffering from SpA represents an exciting new research field and may assist in the differential diagnosis of SpA.

The study analyzed serum hyaluronidase and deoxyribonuclease activity in patients with early arthritis--early rheumatoid arthritis and acute reactive arthritis. The criteria of their differential diagnostics were developed on the basis of data obtained. The genuine methods were applied to analyze hyaluronidase and deoxyribonuclease activity of blood serum based on formation of clot of etacridine acetate (rivanol) with hyaluronic acid and DNA inversely proportionally to their polymerization under the impact of enzymes. The increased serum hyaluronidase and deoxyribonuclease activity was established in patients with early arthritis as compared with control group (p < 0.001). The prevalence of mentioned types of activity under early rheumatoid arthritis as compared with acute reactive arthritis was detected too. The rests for differentiate diagnostics of early rheumatoid arthritis and acute reactive arthritis were developed conformed to criteria of the most useful diagnostic tests in rheumatology.

We present the first evidence demonstrating that small fractions of IgGs of all four subclasses (IgG1–IgG4) from patients with viral (tick‐borne encephalitis), bacterial infections (streptococcal infection or erysipelas), and suppurative surgical infections caused by epidermal staphylococci as well as from patients with autoimmune diseases (systemic lupus erythematosus and multiple sclerosis) are catalytically active in the hydrolysis of supercoiled DNA. The hydrolysis of DNA was analyzed by agarose gel electrophoresis. The catalytic activities of nonfractionated IgGs increased in the following order: tick‐borne encephalitis < suppurative surgical infection < streptococcal infection < multiple sclerosis < systemic lupus erythematosus, whereas IgGs of healthy donors were inactive. However, the pools of antibodies corresponding to any particular disease were characterized by a specific ratio of IgGs of all four subclasses (IgG1–IgG4) and IgGs containing λ‐ and κ‐type light chains, and each of these subfractions of immunoglobulins demonstrated characteristic relative DNase activity. The relative activities of IgGs containing λ‐type light chains may on average be higher, lower, or comparable with those for IgGs with κ‐type light chains. The relative contributions of IgGs of different subclasses to the total activity of IgGs also varied widely in the case of various diseases: IgG1 (7%–45%), IgG2 (0.4%–73%), IgG3 (0%–12%), and IgG4 (9%–66%). Thus, immune systems of patients with different diseases can generate a variety of anti‐DNA abzymes of different types and with different catalytic properties, which can play an important role in the pathogenesis or protection from the development of these diseases. Copyright © 2012 John Wiley & Sons, Ltd.