Nucleic acid aptamers capable of affine and specific binding to their molecular targets have now established themselves as a very promising alternative to monoclonal antibodies for diagnostic and therapeutic applications. Although the main focus in aptamers’ research and development for biomedicine is made on cardiovascular, infectious, and malignant diseases, the use of aptamers as therapeutic or diagnostic tools in the context of rheumatic diseases is no less important. In this review, we consider the main features of aptamers that make them valuable molecular tools for rheumatologists, and summarize the studies on the selection and application of aptamers for protein biomarkers associated with rheumatic diseases. We discuss the progress in the development of aptamer-based diagnostic assays and targeted therapeutics for rheumatic disorders, future prospects in the field, and issues that have yet to be addressed.

Spondyloarthritis (SpA) encompasses a group of chronic inflammatory rheumatic diseases with a predilection for the spinal and sacroiliac joints, which include axial spondyloarthritis, psoriatic arthritis, reactive arthritis, arthritis associated with chronic inflammatory bowel disease, and undifferentiated spondyloarthritis. The prevalence of SpA in the population varies from 0.5 to 2%, most commonly affecting young people. Spondyloarthritis pathogenesis is related to the hyperproduction of proinflammatory cytokines (TNFα, IL-17A, IL-23, etc.). IL-17A plays a key role in the pathogenesis of spondyloarthritis (inflammation maintenance, syndesmophites formation and radiographic progression, enthesites and anterior uveitis development, etc.). Targeted anti-IL17 therapies have established themselves as the most efficient therapies in SpA treatment. The present review summarizes literature data on the role of the IL-17 family in the pathogenesis of SpA and analyzes existing therapeutic strategies for IL-17 suppression with monoclonal antibodies and Janus kinase inhibitors. We also consider alternative targeted strategies, such as the use of other small-molecule inhibitors, therapeutic nucleic acids, or affibodies. We discuss advantages and pitfalls of these approaches and the future prospects of each method.

Background. Currently, observations are accumulating indicating the negative effect of therapy with a number of biologic disease-modifying anti-rheumatic drugs (bDMARDs) drugs on the course of COVID-19. These facts determine the relevance of studying the factors of severe course and unfavorable outcome in immuno-inflammatory rheumatic diseases (IIRD) patients treated with bDMARDs in order to develop tactics for managing this category of patients in a pandemic. Aim. To evaluate the influence of clinical and demographic factors on the risk of development, severity of the course and clinical outcomes of a new coronavirus infection in patients suffering from IIRD and receiving therapy with genetically engineered biological drugs. Materials and methods. A retrospective analysis of the database of the register of patients with IIRD receiving bDMARDs in the Novosibirsk region was performed, which included 318 patients, 94 of whom had indications of having suffered viral infection/pneumonia for the period from 01.04.2020 to 31.12.2020. Results. According to the data obtained, at the time of the analysis, 94 people out of 318 patients with IIRD had a new coronavirus infection. Most (53%) of the patients had a mild infection. At the same time, the nosological form, the use of anti-rheumatic drugs and glucocorticoids did not increase the risks of severe coronavirus infection. When using bDMARDs, only anti-B-cell therapy (rituximab) associated with statistically significant increase in the risk of severe/extremely severe COVID-19. The mortality rate according to the analysis of the register was 6,38%. Conclusion. Patients with IIRD have a high risk of severe coronavirus infection, while the severity of the disease is associated with the type of therapy performed.

Chronic immunoinflammatory rheumatic diseases, such as axial spondyloarthritis (AxSpA), are accompanied by a dysregulation of bone remodeling. Among potential biomarkers of bone metabolism, the Wnt pathway antagonist, Dickkopf-1 (DKK-1), is of particular interest because of its potential to reflect a shift towards joint ossification or osteoporosis, but its diagnostic value needs validation. There is still a lack of stable and efficient methods of measuring serum DKK-1 levels suitable for longitude studies. The use of aptamer-based diagnostic assays could be very promising for this purpose. We generated novel anti-DKK-1 DNA aptamers from a combinatorial library with a pre-defined sequence pattern in the randomized region. This approach showed high efficacy, as only four SELEX rounds of selection produced high-affinity aptamers with dissociation constants ranging from 1.3 to 3.7 nM. A family of their truncated versions was also developed by rational design. Novel DNA aptamers functioned as capture components in a microplate ELISA-like assay with HRP-conjugated anti-DKK-1 antibody as a reporter component. We succeeded in revealing the aptamer/aptamer sandwich pairs that provided an aptamer-only sandwich colorimetric assay. The aptamer/antibody colorimetric test systems were also examined in the analyses of blood serum from AxSpA patients and shown sufficient workability. However, in a number of cases we registered significant differences between assays based on TD10 and DK4 aptamers and made some suggestions about the origin of this effect.

The aim of the study was to analyze the relationship between monocyte subpopulations and phenotype/ functions of monocyte-derived dendritic cells (DCs), as well as DC sensitivity to the tolerogenic effect of dexamethasone.Materials and methods. The study included 15 healthy donors. DCs were generated by cultivating enriched fractions of CD14+ monocytes with or without CD16+cell depletion (CD16-Mo-DCs or CD16+Mo-DCs, respectively) in the presence of interferon alpha (IFNα) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Monocyte subpopulations were obtained by immunomagnetic negative selection.Results. CD16+Mo-DCs were characterized by higher percentage of mature (CD83+CD14-) and lower number of semi-mature (CD14+CD83+) cells, but were similar to CD16-Mo-DCs by HLA-DR and CD86 expression, involved in the presentation of antigens and activation of naive T-cells. and also to co-inhibitory/ tolerogenic molecules B7-H1 and TLR-2. CD16+Mo-DCs displayed higher allostimulatory activity, which was positively correlated with CD86 expression (rS = 0.69; p = 0.027) and negatively – with TLR-2 expression (rS = -0.72; p = 0.1). Allostimulatory activity of CD16-Mo-DCs was positively correlated with the number of mature CD14-CD83+DCs and semi-mature CD14+CD83+DCs. Addition of dexamethasone (10-6 M) into CD16-Mo-DCs and CD16+Mo-DCs cultures led to the delay of DC maturation, the decrease of CD86 and the increase of TLR-2 expression, as well as the increase of cells with co-inhibitory CD86- B7-H1+ phenotype that was positively correlated with the reduction of DC allostimulatory activity. The decrease of CD86+/TLR-2+ index in CD16+Mo-DC population was due to the reduction of CD86+DCs and in CD16-Mo-DC population – to the increase of TLR-2+cells. Dexamethasone possessed higher inhibitory effect on DC maturation in the CD16+Mo-DC cultures.Conclusion. CD14+ monocytes, both contained and depleted by CD16+ cells, can differentiate into DCs when cultured with IFNα. The presence of CD16+ cells in whole blood monocyte pool is associated with generation of DCs showed a more mature phenotype and higher allostimulatory activity. Both CD16- and CD16+ monocyte-derived DCs are sensitive to suppressive effect of dexamethasone. However, dexamethasone tolerogenic effect involves different mechanisms in CD16-Mo-DCs and CD16+Mo-DCs.