Low-Dose Exposures to Airborne Chromium Compounds as a Factor Promoting Genetic and Immunological Risks of Allergic Rhinitis in Children

Introduction: Respiratory allergies in children can be induced by metal allergens, a long-term low-dose inhalation exposure to which can trigger hypersensitivity reactions. Objective: To assess immunological and genetic risks of developing allergic rhinitis in children exposed to low airborne chromium concentrations. Materials and methods: We tested blood samples of 147 schoolchildren experiencing chronic exposure to airborne chromium at the average annual maximum permissible level for blood chromium levels, the immune state (total IgE, specific IgE, CD8+, CD25+, CD95+, IL-1b, and IL-18), polymorphism of the candidate genes PPARA G/C rs4253778 and SULT1A1 Arg213His rs9282861. The sample was divided into two groups: the observation group including 61 children with allergic rhinitis (J30.3) in the medical history and the reference group of 86 hay fever-free controls. Results: We established that the children suffering from allergic rhinitis had 1.2 times higher blood chromium levels, 3.4 times higher total IgE sensitization, 1.2 times higher chromium-specific IgE sensitization, elevated expression of the activation clusters of CD25+ lymphocytes (R2 = 0.58 at p < 0.01) and IL-18 but reduced expression of CD8+ and CD95+ lymphocyte clusters (R2 = 0.51 at p < 0.01) compared to the controls. We also found alleles and genotypes posing the risk of health impairments associated with polymorphisms of the candidate genes in the observation group (RR = 1.2–1.8), namely the C allele of the PPARA gene (OR = 2.51; CI: 1.28–4.94); the A allele (OR = 1.90; CI: 1.19–3.03), and AA genotype (OR = 2.47; CI: 1.16–5.24) of the SULT1A1 gene. Conclusions: We established that the low-dose exposure to airborne chromium compounds at the average annual MPL accounts for excessive chromium concentrations in biological fluids and imbalance of the immunological profile against single nuclear polymorphisms of the detox gene SULT1A1 Arg213His rs9282861 (the А allele) and antioxidant gene PPARA G/C rs4253778 (the allele С) and poses risks (RR = 1.2–1.8) of allergic rhinitis for the exposed children. We suggest that chromium-specific IgE, levels of expression of CD8+, CD25+, CD95+ lymphocyte clusters, IL-18, polymorphisms of the candidate detox SULT1A1 and antioxidant PPARA genetic variations should be used for early diagnosis and subsequent prevention of hay fever in children upon low-dose exposure to airborne chromium compounds.