Immunoglobulins in tears and sera in patients with atopic dermatitis

The aim of the study was to investigate the role of circulating (i.e., present in the serum) and locally produced (i.e., in the lamina propria of mucous membranes) immunoglobulins including IgE. The IgG, IgA, IgM immunoglobulins, and IgE (total and specific) were measured in patients' sera with atopic dermatitis (AD) (n = 93). As control subjects 83 healthy volunteers, matched for sex and age, were included. The IgG and IgM levels were within the normal range. Mean value of the total IgA (2.55 +/- 0.26 g/L, in controls 1.49 +/- 0.32 g/L) and IgE (609 IU/mL, in controls below 40 IU/mL) levels were significantly elevated (p < 0.05) in sera of AD patients. Based on the serum total IgE levels (above or below 40 IU/mL) the patients were divided into RAST-positive and RAST-negative types of allergy, respectively. RAST-positive AD (n = 79) showed hypersensitivity to inhalant and food allergens determined by the specific IgE test. The majority of RAST-positive AD cases (n = 68) presented only skin manifestations, while the rest of the patients (n = 11) had rhinoconjunctivitis as well. RAST-positive AD patients with rhinoconjunctivitis showed an increased IgE level in tears (above 10 IU/mL). The specific IgE test positivity in tears correlated with elevated serum total IgE levels and specific IgE positivity (r = 0.925). Total and allergen-specific IgE in the tears can be used to diagnose allergy in vitro. It is believed that the mucosal permeability is enhanced in the atopic inflammatory process, and this may facilitate the transmission of environmental allergens.