Biological Role of Human Bactericidal/Permeability-Increasing Protein in Helicobacter Pylori–associated Upper Gastrointestinal Tract Diseases in Children

The prevalence of Helicobacter pylori infection (HP) varies across geographic regions and remains heterogeneous. Approximately one-third of children worldwide are infected with H. pylori, with primary acquisition occurring during childhood. The immune response to inflammatory diseases is mediated by the synthesis and release of antimicrobial peptides, which serve as protective factors. Human bactericidal/permeability-increasing protein (hBPI) is among these antimicrobial peptides, and its mechanisms of antimicrobial defense are exerted through multiple pathways. Investigation of the relationship between hBPI levels and morphological changes in the upper gastrointestinal mucosa in H. pylori–associated diseases in children may enhance understanding of the biological significance of this antimicrobial peptide in the host immune response. Objectives of the study. To determine the serum levels of human bactericidal/permeability-increasing protein in children with upper gastrointestinal tract diseases associated with H. pylori infection and to elucidate its role in the development and progression of the infectious process. Material and Methods. A total of 60 patients aged 10 to 17 years were examined. Subgroup 1 comprised 30 children with gastroduodenal diseases associated with H. pylori. Subgroup 2 included 30 children with gastroduodenal diseases not associated with H. pylori. The control group consisted of 20 apparently healthy children matched for age and gender. Diagnosis was established by laboratory, endoscopic, and histological examinations. Determination of hBPI levels levels in serum was performed by enzyme-linked immunosorbent assay using a commercially available Human BPI ELISA Kit (Elabscience Biotechnology, Houston, TX, USA). The study protocol was approved by the Bioethics Committee of the Zaporizhzhia State Medical and Pharmaceutical University. The study was conducted in accordance with ethical standards and principles for medical research involving human subjects and adhered to fundamental bioethical norms. Informed consent was obtained from all participants or their legal guardians prior to enrollment (Protocol No. 3, dated October 28, 2024). Statistical analysis was performed using the licensed Statistica for Windows software package, version 13.0 (serial number JPZ8041382130ARCN10-J). Data are presented as arithmetic mean (M), standard deviation (σ), and standard error of the mean (m) for participants stratified into categories that met the criteria of normality. Associations between variables were evaluated using Spearman's rank correlation coefficient (r). To assess the significance of differences between the compared groups, the Student’s t-test for small samples was used, supplemented by the nonparametric Mann–Whitney U test when appropriate. Differences were considered statistically significant at p < 0.05. The research was conducted under the departmental project entitled “Predicting the course of the most common inflammatory diseases of childhood” (registration number 01121U107520, 2020–2026). Results. Serum levels of human bactericidal/permeability-increasing protein (hBPI) in the study group were 2.2 times higher than those in the control group (p < 0.05). In patients with erosive gastroduodenitis, hBPI levels were increased 3-fold compared with the control group (p < 0.05). Gender differences were observed: in girls with H. pylori infection, hBPI levels were elevated by 80% (p < 0.05), whereas in boys with H. pylori infection, serum hBPI levels were increased more markedly, by 300% (p < 0.05). In the presence of H. pylori infection, increased inflammatory activity was associated with elevated hBPI levels (p < 0.05). In the absence of H. pylori, the highest serum hBPI levels were observed in cases with grade 1 lymphoplasmacytic infiltrate (p < 0.05) and with minimal inflammatory changes (p < 0.05). Conclusions. The course of upper gastrointestinal tract diseases associated with H. pylori in children is accompanied by increased hBPI levels, which correlate directly with the severity of mucosal lesions and the extent of mucosal involvement. Gender differences in hBPI levels were identified, with girls in the control group exhibiting higher hBPI levels than boys.