MECHANISMS OF CLINICAL-IMMUNOLOGICAL DEVELOPMENT OF DISEASES WITH BRONCHOOBSTRUCTIVE SYNDROME IN CHILDREN

Аннотация

Bronchoobstructive syndrome (BOS) is a common pathological condition in pediatric practice, accompanied by narrowing of the airways, which occurs against the background of diseases of various etiologies. BOS is manifested by difficulty breathing, wheezing, prolonged expiration and is associated with inflammation, edema, increased secretion or muscle spasm, which causes bronchial obstruction. This syndrome is more common in children against the background of bronchiolitis, bronchial asthma, allergic rhinitis,viral respiratory infections, as well as congenital anomalies. Relevance: Bronchoobstructive syndrome (BOS) is one of the most common respiratory diseases in children. According to the World Health Organization (WHO), BOS is observed in 30–50% of cases among children under 5 years of age every year. Especially in diseases such as bronchial asthma, viral bronchiolitis, allergic rhinitis, the development of CSFhas anegative impact onthequality oflife, growth and development ofchildren. In recent years, scientific research onthe role of age-specific immunological changes, genetic predisposition, environmental factors and epigenetic mechanisms in diseases associated with this syndrome has been deepening. In particular, it has been found that Th2- type inflammation, increased levels of interleukins (IL-4, IL-5, IL-13), eosinophils and IgE, as well as epithelial barrier dysfunction play a key role inthepathogenesis ofCSF. In modern pediatrics, early identification of factors causing CSF, assessment of the immunological status and the use of individual treatment approaches are of great importance. Especially in preschool children, bronchoobstructive conditions are often theprimary sign of asthma, and their timely and correct assessment is crucial in preventing future chronic respiratory diseases. Also, factors such as antibiotic-resistant infections, improper and self-medication, environmental pollution, and passive smoking are increasing the severity ofBOS. Therefore, 98,7:ROTCAFTCAPMI .SECNEICSLACIDEM,5202,yaM,5emuloV gro.srehsilbupcimedaca.www in-depth study of this syndrome through complex immunological, clinical, and epidemiological approaches is relevant not only in clinical practice, but also in health policy. Keywords: Bronchoobstructive syndrome, Etiology, Immune response, Th2- lymphocytes, Eosinophils, Children, Allergy, Bronchial asthma, Pathogenesis. Main part: In the development of bronchial obstruction in children, age-related features of the structure of the bronchial tree, which are characteristic of children in the first years of life, play a certain role. Factors such as prolonged sleep, frequent crying, and lying on the back in the first months of life also undoubtedly affect the dysfunction of the respiratory system in a small child. Early childhood is characterized by the imperfection of many immunological mechanisms: the formation of interferon in the upper respiratory tract, the level of immunoglobulin A in the blood serum (by the end of the first year of life it is 28% of the adult level), since secretory immunoglobulin A (maximum values ​ ​ ​ ​ are determined only at 10-11 years of age), the functional activity of the T-system of immunity also decreases. In addition, perinatal pathology, allergic history, bronchial hyperreactivity, rickets, dystrophies, thymus hyperplasia, early artificial feeding, and respiratory diseases observed in children aged 6-12 months also play an important role in the development of bronchoobstruction. Etiologyandpathogenesis Among the etiological factors of bronchoobstructive syndrome, the following are distinguished: 1. Viral infections: especially respiratory syncytial virus (RSV), parainfluenza, adenoviruses, rhinoviruses. 2. Allergens: dust, animal hair, plantpollen, housedust mitewaste. 3. Bacterial infections: Streptococcus pneumoniae, Haemophilus influenzae. 4. Atopic background: the presence of allergic diseases in parents makes the child's immunesystem hyperreactiveto suspected antigens. Pathogenesis is complex and occurs through immune and neurohumoral mechanisms: Immunological stage: In diseases accompanied byCSF, aTh2-type immuneresponse usually prevails. In this case, interleukins such as IL-4, IL-5, IL-13 are activated and attract eosinophils. Proinflammatory mediators (for example, major basic protein) contained in eosinophilgranules damage thebronchial epitheliumand lead to edema and hypersecretion. Bronchial hyperreactivity: Histamine, leukotrienes and prostaglandins released by mastcells cause spasm ofbronchial muscles. Neuroimmune regulation: Stimulation of sensory nerve fibers increases bronchoconstriction through vagal reflexes. Epithelial barrier disruption: Viruses or allergens damage the bronchial epithelium, weakening itsprotective function and leading theimmunesystem toa hypersensitivestate. Clinical manifestations 98,7:ROTCAFTCAPMI .SECNEICSLACIDEM,5202,yaM,5emuloV gro.srehsilbupcimedaca.www Diseases associated with BOSusually havet