Soluble CD14 and total IgE in the serum of atopic and nonatopic adolescents in relation to environmental factors: a pilot study.

The CD14 receptor is expressed on the surfaces of monocytes, macrophages, and, to a lesser extent, of activated granulocytes and B lymphocytes (mCD14). It also exists in soluble form in the serum (sCD14), in which it binds microbial compounds and indoor allergens. The objectives of this study were to see whether serum sCD14 concentrations could be used as a marker of atopic disorders and to estimate the effects of environmental factors (tobacco smoke exposure, childhood residence in urban or rural areas, and having a pet) on sCD14 and IgE values. Mass fraction of sCD14 and total IgE were determined in the sera of atopic (N=53) and non-atopic (N=35) participants using the standard enzyme-linked immunosorbent assay. Exposure to pets and environmental tobacco smoke was estimated based on the International Study of Asthma and Allergies in Childhood questionnaire (ISAAC). Median sCD14 concentration was significantly lower in atopic than in non-atopic girls (3.49 vs. 3.83 μg mL(-1); p<0.010). The number of smokers at home positively correlated with the sCD14 level in atopics, and urban atopics had significantly lower sCD14 levels than rural atopics (3.47 vs. 3.92 μg mL(-1), p=0.028). Median total IgE concentration was significantly lower in atopic pet owners than in atopics with no pets (161 vs. 252 kIU L(-1); p=0.021). In conclusion, while sex and environmental factors might be involved in sCD14 expression, particularly in atopics, we found no correlation between sCD14 and total IgE concentrations. The usefulness of sCD14 as a marker of atopic disorders should be investigated further, particularly in relation to the severity of allergic disorders.