The role of surfactant protein SP-D in the functioning of innate and adaptive immunity in children with bronchial obstruction

Introduction. Bronchial obstruction syndrome remains a significant issue in pediatrics. One of the non-invasive diagnostic methods in children is the determination of local nonspecific immune defense indicators. Aim. To study the role of surfactant protein SP-D in the functioning of the innate and adaptive immunity in children with bronchial obstruction. Materials and methods. A total of 183 children were examined: Group 1 consisted of patients with SP-D protein concentrations ranging from 100 to 500 ng/mL (n=21), Group 2 with less than 100 ng/mL (n=92), and a control group of healthy children with SP-D levels above 500 ng/mL (n=70). All children underwent enzyme-linked immunoassay to determine the concentrations of surfactant protein SP-D in exhaled breath condensate, and levels of IgA, IgM, IgG, IgE, and α-defensins 1-3 in serum. Results. The content of IgA was found to be 44.4% and 33.3% lower in the first and second groups, respectively, compared to the control group. Higher levels of IgE were detected in Groups 1 and 2 compared to healthy children. No differences were observed in IgM and IgG levels among the study groups. The concentration of α-defensins 1-3 was 6.8 times lower in Group 1 compared to the control group, and 1.7 times lower in Group 2. Conclusion. Reduced levels of SP-D affect both innate and adaptive immunity indicators. Low SP-D protein values were associated with decreased IgA and α-defensins levels, as well as high IgE concentrations.