Immunoregulation indices as markers of the effect of phenol bioexposure in children with atopic dermatitis

Introduction. Long-term and low-dose exposure to technogenic chemical compounds (using phenol as an example) mediates disruption of immune regulation mechanisms and increases the risk of allergic diseases in preschool children. Materials and methods. The study included 4–7 years children diagnosed with atopic dermatitis, living in an area where the average daily dose of airborne exposure to phenol was 0.00408 mg/(kg×day), the maximum single dose was 0.01632 mg/(kg×day). The study groups were created according to the criterion of blood phenol biocontamination (p=0.033): Sixty nine children in the observation group; 105 in the reference group. The study relied on using cytofluorometry, enzyme immunoassay and allergosorbent research methods. Results. In the observation group, the population of CD8+, CD19+ cells was found to be significantly (p=0.005–0.048) increased by 50% and CD95+ cells by 15%; the number of cell phenotypes of CD4+CD25+CD127 –-lymphocytes by 70% and AnnexinV-FITC+7AAD+-cells by 40% against a 10% decrease in lymphocytes expressing the HLA-DR marker relative to the values established in the reference group. Intergroup comparison of the level of specific sensitization revealed the titer of IgG specific to phenol to be by 15% higher in the children from the observation against the levels established in the reference group (p=0.010). The results of mathematical modelling demonstrated the dependence of hyperproduction of IgG specific to phenol on the phenol levels in blood (RR = 1.46; 95% CI = 1.10–1.93). Limitations. The limitations of the study are related to the limited sample size in the surveyed groups of the child population. Conclusion. Thus, a specific immunological phenotype is formed in children with atopic dermatitis from the observation group and increased bioexposure to phenol. It is characterized by an imbalance in the parameters of immune regulation and specific sensitization such as the number of CD4+CD25+CD127-, HLA-DR and Annexin V-FITC+7AAD+ lymphocytes, as well as IgG specific to phenol, forming an increased relative risk of developing atopic reactions (RR=1.46). This allows recommending these indicator parameters as markers of effect for identifying and reducing the risk of developing immune regulatory disorders in exposed to phenol children with atopic dermatitis.