The level of antimicrobial peptides in different clinical forms of urinary tract infections in children

Abstract

The aim. To study the content of antimicrobial peptides in the serum of children with urinary tract infections depending on the clinical form of the disease and to establish their pathogenetic role in the development of various clinical forms of pathology. Materials and methods. The study groups consisted of 84 children (mean age – 10.0 ± 1.3 years). The main group was divided into subgroups: the first subgroup – 17 children with acute pyelonephritis, the second subgroup – 21 patients with chronic pyelonephritis, the third subgroup – 16 patients with acute cystitis, the fourth subgroup – 10 patients with unspecified urinary tract infections. The control group consisted of 20 relatively healthy children. The study of the content of cathelicidin, hepcidin and lactoferrin was performed by enzyme-linked immunosorbent assay. Results. The development of urinary tract infection was accompanied by a statistically significant increase in the content of cathelicidin (P < 0.05). The highest level of serum cathelicidin was registered in children of the first (P <0.05) and third subgroups (P < 0.05). In the other two subgroups, the level of LL-37 had only a trend towards increasing (P > 0.05). The level of hepcidin in the main study group was statistically lower than in the control group (P < 0.05). The development of chronic pyelonephritis and acute cystitis occurred amid a statistically significant decrease in hepcidin levels by 2.5 and 1.7 times (P < 0.01 and P < 0.05, respectively). The level of lactoferrin in the general group was within the control group figures (P > 0.05), however, there was a statistically significant decrease in serum lactoferrin in a subgroup of children with unspecified urinary tract infections (P < 0.05). We determined a relationship between hepcidin and lactoferrin levels in the investigated groups and found a clear direct relationship in a subgroup of children diagnosed with chronic pyelonephritis (r = 0.58, P < 0.01). Conclusions. Each nosological form of urinary tract infection has its own configuration of antimicrobial peptides. The analysis of the relationship between hepcidin and lactoferrin, the antimicrobial peptides that limit the access of the pathogens to serum iron, indicates the synchronization of the body’s defense mechanisms aimed at eliminating the pathogen.