Alla Yu. Rubina

One of the biomarkers of biggest clinical importance in rheumatoid arthritis (RA) is rheumatoid factor (IgM RF). The rheumatoid factor has insufficient sensitivity and specificity, therefore, to increase the diagnostic information of the test, acute phase proteins were used as concomitant biomarkers. Using biological microchips, we measured IgM RF, C-reactive protein (CRP) and Serum amyloid protein A (SAA) in patients with RA (n = 60), ankylosing spondylitis (AS) (n=55), systemic lupus erythematosus (SLE) (n=20) and healthy donors (HD) (n=9). It was shown that the medians of IgM RF concentrations are significantly higher (p<0.01) in patients with RA compared to patients suffering from other diseases and healthy donors. CRP and SAA were also significantly increased (p<0.05) in patients with RA and AS compared with SLE and HD. It has been shown that the complex determination of three biomarkers in differentiating RA patients with the comparison group had a higher diagnostic sensitivity than the isolated determination of IgM RF, while the addition of SAA makes the greatest contribution to improving the diagnostic characteristics of the biomarker panel: the use of a logistic regression model based on IgM RF and SAA allowed to increase the diagnostic sensitivity of the analysis from 58.3% to 65%. Thus, the developed microarray-based method can be used to detect and elucidate the diagnostic characteristics of RA biomarkers; however, further use requires validation of the obtained results on an expanded sampling.

Cytokines and acute phase proteins play an important role in the development of the immune response during inflammatory reactions. Depending on the type of disease, the development of inflammation is accompanied by changes in concentrations (both decrease and increase) of not one, but many inflammatory biomarkers. Here, a quantitative microarray-based method for multiplex immunoassay of eight biomarkers of human inflammation, namely acute phase proteins (C-reactive protein, serum amyloid protein A) and cytokines (IL-6, IL-8, IL-17, IL-18, IP10/CXCL10, TNFα) was developed and the possibility of its use for the detection of inflammatory biomarkers in a culture medium has been demonstrated. The developed method can be used to evaluate changes of the inflammatory biomarker profile induced by different agents or to determine the concentrations of biomarkers after activation of cells while studying different diseases with the help of in vitro models.

The lack of specific clinical symptoms for patients in the early stage of rheumatoid arthritis (RA) has created strong interest in the laboratory diagnosis of RA. The main laboratory markers of RA, rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPAs), can be found in patients with other pathologies and in healthy donors. Even today, there is no single laboratory test that can diagnosis RA with high sensitivity and specificity. To improve the diagnosis and treatment of RA, alternative biomarkers, including 14-3-3η protein, connective tissue growth factor (CTGF), antibodies against PAD4, antibodies against BRAF, and anti-acetylated and anti-carbamylated protein antibodies have been studied extensively. The use of a multiple biomarker approach, the simultaneous measurement of a set of biomarkers, is an alternative strategy for the diagnosis of RA and for predicting the therapeutic effect of biological disease-modifying antirheumatic drugs (DMARDs). However, despite the large number of studies, only a few biomarker combinations have been validated and can be applied in clinical practice. In this article, results of studies focused on the multiple biomarker approach (both multiplex and combined single-analyte assays) to diagnose RA and to predict response to biological drug therapy are reviewed. Additionally, general factors limiting the use of multiplex analysis in RA diagnostics and therapy are discussed.

Cytokines and acute phase proteins play an important role in the development of the immune response during inflammatory reactions. Depending on the type of disease, the development of inflammation is accompanied by changes in concentrations (both decrease and increase) of not one, but many inflammatory biomarkers. Here, a quantitative microarray-based method for multiplex immunoassay of eight biomarkers of human inflammation, namely acute phase proteins (C-reactive protein, serum amyloid protein A) and cytokines (IL-6, IL-8, IL-17, IL-18, IP10/CXCL10, TNFα) was developed and the possibility of its use for the detection of inflammatory biomarkers in a culture medium has been demonstrated. The developed method can be used to evaluate changes of the inflammatory biomarker profile induced by different agents or to determine the concentrations of biomarkers after activation of cells while studying different diseases with the help of in vitro models.

We propose an approach that allows simultaneous determination of the levels of M and G isotypes of antibodies to the panel of glycans using microarrays. The level of IgG antibodies to 3’-O-su-Le^a glycan detects patients with colorectal cancer with a sensitivity of 69.77% and specificity of 62.75%. The percentage of correctly classified colorectal cancer patients with the use of a combination of two markers IgM antibodies to glycans 3’-sialyl-TF and 3’-O-su-Le^a is as high as 74.23%. The levels of IgM antibodies to 3’-O-su-Le^a glycan differ significantly in patients with and without regional metastases. The levels of some of antiglycan IgM or IgG antibodies differed significantly in patients with tumors of different location and differentiation.

Glycans and anti-glycan antibodies (AGAs) are essential for infiltration of inflammatory cells in various allergies. The glycocalyx structure of the cells is modified during disease progression, and...

The immunological profiles of human specific IgE (sIgE) and specific IgG4 (sIgG4) vary by genetic predisposition, living conditions in different geographical locations and patient’s age. The aim of our study was to analyze sIgE and sIgG4 patterns and their age-dependent changes in patients from the Moscow region. For identifying sIgE and sIgG4 profiles the blood samples from 513 patients aged 6 months to 17 years who were showing symptoms of allergic diseases were analyzed using microarrays containing 31 allergens. The highest sIgE prevalence was observed for birch pollen (32%) among pollen allergens, cat dander (24%) among indoor allergens, and egg whites (21%) among food allergens. The most common sIgG4 response was developed toward egg whites (80% of patients). Age-related elevation was identified for patients with increased sIgE to pollen allergens and indoor allergens (cat or dog dander and house dust mites). For each allergen, the proportion of cases with significant levels of sIgG4 appeared to increase with patients’ age. The data on allergen-specific sIgE and sIgG4 prevalence show both general trends and some local special aspects that are indicative for the Moscow region. This information should be useful in terms of epidemiology of allergic diseases.

Glycans and anti-glycan antibodies (AGAs) are essential for infiltration of inflammatory cells in various allergies. The glycocalyx structure of the cells is modified during disease progression, and this modification is possible to evaluate by assessment of AGAs. A printed glycan array with 55 immobilized glycans and immobilized antibodies to IgG, IgA, and IgM was used to study the changes in AGA profiles in bronchial asthma (BA). Levels of antibodies to certain glycans in BA patients statistically differed from levels in healthy donors (p < 0.0007 by the Mann-Whitney test); the glycan set included 6Su-6`-SiaLec, Sia LeX, Sia6Htype2; Tαα, Manβ1-4GlcNAc, and Manα1-4Manβ. The obtained results help to better understand the mechanisms of the cell-mediated immune response in bronchial asthma and other types of allergic reactions.