Features of hapten specific sensitization and immune status in different student age groups

In recent decades, the frequency and prevalence of allergic diseases among children have increased dramatically. The aim of the current study was to investigate features of hapten specific sensitization and immune status in different student age groups during high-intensity educational process. A number of parameters related to specific sensitization to metals and organic compounds were studied: 67 first grade children and 35 6-7 grade children attending school with a high-intensity educational process simultaneously chronically exposed to exogenous chemical haptens (the observation group No. 1 and observation group No. 2, respectively); in 20 primary school students and 27 6-7 grade students educated in the absence of excessive exposure to negative factors (the comparison group No. 1 and comparison group No. 2, respectively). Measurement of serum IgE immunoglobulins specific to manganese, IgE specific to nickel, formaldehyde as well as IgG specific to benzene, lead, phenol was carried out by using enzymeallergosorbent test; level IL-4 (Th2) was assessed by enzyme-linked immunosorbent assay; level of CD19⁺ receptor expression on lymphocytes was estimated by flow cytometry. A simple linear regression analysis was used to analyze the data. To test null hypotheses about equality of mean values between two independent groups with a normal distribution, a two-sample Student’s t-test was used. It was found out that the degree of specific sensitization changed with age in students chronically exposed to exogenous haptens. The level of specific sensitization to organic compounds increases markedly in high school students vs. to primary school children (IgG level to phenol elevated by 1.5 times) paralleled with profoundly increased production of Th2 cytokines (IL-4 – by 1.8-fold) as well as activated humoral immunity (percentage of CD19⁺ lymphocytes increased by 1.3-fold). Probable causative link was found between amount of serum exogenous phenol hapten and increased concentration of phenol-specific IgG (F = 140.81; R² = 0.53; p < 0.001). Hapten-specific sensitization in school students increases progressively with age or duration of hapten exposure.