The place of endogenous antimicrobial peptides in the pathogenetic mechanisms of the development of community-acquired pneumonia caused by Streptococcus pneumoniae among infants

Abstract

A comprehensive survey was carried out in 30 children with community-acquired pneumonia aged 2 months to 3 years old, among them in 18 children the disease was caused by Streptococcus pneumoniae, and in the remaining 12 patients — by Gram-negative flora. All children underwent the evaluation of the severity of the condition using the PRESS scale, according to which it was found that most patients had severe course of pneumococcal pneumonia. The analysis showed that the development of pneumococcal pneumonia in children occurred against the background of a decrease in the serum content of vitamin D metabolites and the activity of antimicrobial peptides, in contrast to pneumonia caused by Gram-negative pathogens. In the blood serum of children with pneumococcal pneumonia, there was detected a decrease in the content of β1-defensins by 2.6 times, LL-37 — by 3.7 times and human bactericidal permeability-increasing protein — by 2.8 times in comparison with the control group (p < 0.05). It has been proved that inadequate activation of antimicrobial peptides against the background of a deficiency of vitamin D metabolites in infants with pneumonia caused by Streptococcus pneumoniae is one of the pathogenetic links leading to a severe course of the disease.

Keywords

• community-acquired pneumonia
• Streptococcus pneumoniae
• 25-hydroxyvitamin D
• β1-defensin
• cathelicidin LL-37
• bactericidal permeability-increasing protein
• infants