Integrated Analysis of Immunological Blood Parameters in Preschool Children With Recurrent Respiratory Infections

Abstract

Background. Recurrent respiratory infections are a very pressing problem in everyday pediatric practice. They are most commonly diagnosed in preschool children. According to different researchers, their incidence varies considerably (6-30%). The temporary immaturity of immune system is thought to be one of the causes of frequent episodes of acute respiratory infections (ARI). Aim: To determine the state of interdependence between the particular indicators of complex immunological blood test and the frequency of ARI episodes in preschool children. Materials and methods. A total of 26 children (11 boys and 15 girls) aged 1-4 years, undergoing inpatient treatment on ARI, were involved in the clinical study. The number of ARI episodes during the previous year of their life was taken into account. Additionally, two integral indices of ARI recurrence, specifically the infection index and resistance index, were calculated. The children underwent a clinical blood test. Also, the particular indicators of humoral and cellular immunity, functional activity of immune cells (neutrophil phagocytic activity (PhA), lymphocyte blast transformation reaction), complement system (C3c, C4) and the several classes of circulating immune complexes (CIC) were analyzed. The statistical processing of the digital data was performed using IBM SPSS Statistics 28 licensed software with the calculation of the confidence interval (CI) for the main indicators. Results. The prevalent majority of the examined children (80.8%) had an increased serum CIC(small) level. There was a moderate positive correlation between the resistance index values and the CIC(small) level [ρ = 0.392; p = 0.048; CI: 0.072–0.644]. The tightest interdependence was found in the following pairs of studied indicators: 1) CIC(medium)*CIC(small) [ρ=0.732; p<0.001; CI: 0.471–0.875]; 2) C3c*C4 [ρ=0.658; p<0.001; CI: 0.352–0.837]; 3) CIC(large)*Ig(A+M+G) [ρ=0.643; p<0.001; CI: 0.330–0.829]; 4) PhA(spontaneous)*PhA(induced) [ρ=0.601; p=0.001; CI: 0.267–0.806]. A linear regression analysis showed that the predicted resistance index was dependent on only one of the immunological blood parameters considered, specifically total leukocyte antigen. Among other possible predictors, the impact of this antigen on the dependent variable was 18.4%. Conclusions. The particular indicators of a complex immunological blood test are highly interrelated. The results obtained should be taken into account when developing an integrated model for predicting the likelihood of recurrent ARI episodes in preschool children.