Puhachova K. Prognostic significance of 25-hydroxyvitamin D and cathelicidin LL37 in the course of reactive arthritis in children.

The thesis is devoted to increase the effectiveness of diagnostics and prediction of the reactive arthritis course in children on the basis of determining clinical, biochemical, immunological and instrumental features of the course of reactive arthritis. It has been specified that reactive arthritis in children is characterized by a significantly lower serum 25-hydroxyvitamin D compared to healthy children (p<0,05). The inverse correlation between the content of serum 25-hydroxyvitamin D and the indices of acute phase of inflammation in patients with ReA (p <0,05) has been determinated. The content of 25-hydroxyvitamin D can be used as a marker of the severity of inflammatory diseases of the joints, since its low content is associated with a greater number of involved joints (p<0,02). It is proved that ultrasound joint research is a significantly more sensitive method for visualizing indications of arthritis compared with the X-ray method (p<0,01). The most common pathological indication of arthritis according to ultrasonography data in patients with ReA was synovial effusion (p<0,005). For patients with acute course of ReA an exudative synovitis is attributable, whereas the chronic course of ReA is characterized predominantly by effusion and synovial hypertrophy (p<0,05). The prognostic markers of the unfavorable course of ReA in children have been identified. The prognostic criteria for the development of chronic and recurrent course of reactive arthritides in children is insufficient content of serum 25-hydroxyvitamin D, namely if its level is less than 20 nmol/l in the blood, the level of cathelicidin LL37 in blood > 15,6 ng/ml, the level of IL-4 is more than 3,37 pg/ml, the level of the second fraction of blood glycosaminoglycans less than 3,5 Units, the increase of the ratio of CD4/CD8, as well as such macromorphological changes in the joints as hypertrophy of the synovial membrane and effusion in the joint bag according to ultrasonography of the joints. The four steps of logistic regression analysis were performed and a mathematical model for prognostication of the adverse course of reactive arthritis in children was constructed. The developed prognostic mathematical model provides the clinician with a reliability of 89% to predict the nature of the course of reactive arthritis, which will individualize the purpose of treatment and rehabilitation measures and thus increase the effectiveness of treatment and dispensary of this category of patients. The practical value is that the results of the study substantiate the need for a complete physical examination of patients with reactive arthritis with the definition of serum 25-hydroxyvitamin D, cathelicidin LL37 and ultrasound examination of joints, which allows an objective assessment of the risk level of developing an unfavorable course of the disease