REACTIVE ARTHRITIS IN THE CONTEXT OF CONNECTIVE TISSUE DYSPLASIA – THE ROLE OF THE ORGANISM'S MICROBIOME

Abstract

Introduction: The course of reactive arthritis (ReA) depends on several factors related to its etiology and pathogenesis, 
but it is also determined by the condition of the organism in the period preceding the disease. Reactive arthritis in the context 
of connective tissue dysplasia and the characteristics of the microbiome may have a more severe course and an increased 
risk of the chronicity of the joint inflammatory process. 
Research objective: To assess the impact of the organism's microbiome in children with reactive arthritis in the context 
of connective tissue dysplasia (CTD) on the course and outcomes of the disease. 
Materials and Methods: Design: cross-sectional clinical study. Research was conducted at the clinical base of the 
University Hospital of the NCJSC "Semey Medical University" between 2019-2022. The population group (without ReA) 
consisted of 288 children aged 6 to 18 years. The main group of children with reactive arthritis included 146 patients, of 
whom 50 had connective tissue dysplasia, divided into two age categories: 6-12 years (49, including 23 with CTD) and 13-18 
years (97 and 27, respectively). 
The research methods included a comprehensive examination of children according to the Diagnostic and Treatment 
Protocol, determination of the presence of CTD based on a combination of clinical signs, and microbiome composition 
analysis using multi-ion chromatography mass spectrometry, as well as statistical methods. 
Results: Significant differences were identified in the structure of the organism's microbiome and related parameters 
between the examined groups. In the presence of ReA, compared to the population group, a decrease in the content of the 
most common resident microorganisms and an increase in transient microorganisms, microscopic fungi, and organisms not 
normally found in the body were observed in the 13-18-year age group. 
A comparative analysis of subgroups of children with ReA, with and without CTD, also revealed a lower content of 
resident microorganisms and an increase in the presence of non-normal forms of microorganisms in the latter group. 
Higher levels of plasmalogen were found in both age groups of children with ReA without CTD. In contrast, the presence 
of CTD was associated with a higher level of endotoxin. When comparing these results with the control group, significant 
differences were noted in overall load indicators, related to microbiome imbalance, plasmalogen, and endotoxin levels. 
Clinical progression analysis showed an increased duration of joint symptom persistence and a higher risk of chronicity in 
the presence of coexisting CTD combined with microbiome changes. 
Conclusion: The data obtained allowed us to formulate the following conclusions: 
• The state of the microbiome in children with reactive arthritis is characterized by an imbalance, which involves a 
decrease in the content of resident microorganisms and an absolute and relative increase in transient and potentially 
pathogenic microorganisms, a known risk factor. 
• The presence of CTD determines a greater severity of the microbiome imbalance, including in terms of integral 
indicators, plasmalogen, and endotoxin content, which serves as a risk factor for the potentiation and persistence of the 
inflammatory process in the joints. 
• This combination is clinically significant, as confirmed by the longer duration of the main clinical and laboratory 
signs of ReA in children with undifferentiated CTD.