Age-related features of mucosal and systemic immunity in smokers

Aim. To evaluate the features of local and systemic im­munity in smokers of different age groups. Materials and Methods. Here we collected venous blood and oropha­ryngeal swabs from conditionally healthy men. A total of 59 participants were included: 20 individuals aged 18-25 years and 39 individuals aged 45-60 years. Each age group was subdivided into smokers and non-smokers. The aver­age smoking history was 5 years in the younger group and 28 years in the older group. Total leukocyte count and the proportions of different cell types in blood and oropharyn­geal secretions were assessed using light microscopy. Neu­trophil cytotoxic activity was evaluated using the nitro blue tetrazolium test. Concentrations of interleukin-8 (IL-8) and IL-18, IgA, and IgE were determined in blood plasma and supernatant from oropharyngeal swabs by enzyme-linked immunosorbent assay. Results. Age-related changes affect­ed both local and systemic immunity. A reduction in mac­rophage numbers as well as IL-18 and IgA levels in oro­pharyngeal washes were accompanied by an increased pro­duction of pro-inflammatory cytokines IL-8 and IL-18 and a rise in circulating neutrophils. In individuals aged 18-25 years (with an average smoking history 5 years), an increase in blood monocytes and a sharp decrease in IL-8 level were observed, along with a twofold reduction in leukocytes in oropharyngeal washes. In smokers aged 45-60 years, there was a trend toward increased IgA and IgE plasma levels, alongside a significant decrease in IgA and IL-18 in the oral mucosa. Conclusion. The impact of smoking and the dura­tion of exposure to tobacco smoke on the local and systemic immunity of smokers from different age groups is primari­ly reflected at the local level. Smoking exacerbates age-re­lated weakening of the oral mucosal barrier properties and induces systemic immune shifts, even with a short smoking history.