Cc-chemokine eotaxin as a marker of efficacy of specific immunotherapy in patients with intermittent IgE-mediated allergic rhinoconjunctivitis.

Background: Allergen-specific immunotherapy (SIT) is believed to be a valuable remedy in several allergic diseases; however, an accurate immunological marker of the efficacy of this treatment method has not been found yet. Cc-chemokine eotaxin, owing to its selective action on eosinophils, seems to play an important role in the pathophysiology of allergic response. The purpose of this study was to assess the usefulness of eotaxin in monitoring of SIT efficacy in patients with IgE-mediated allergic rhinoconjunctivitis.

Methods: One hundred and twenty-two patients with seasonal IgE-mediated allergic rhinoconjunctivitis due to tree- (birch, n = 42; hazel/alder, n = 14) or grass/cereal- (n = 66) pollen received allergen-specific immunotherapy. Serum eotaxin levels were determined four times in every patient, shortly before immunotherapy (Evaluation 0), immediately after the treatment (Evaluation 1), in the height of pollen season (Evaluation 2) and at least 2 weeks after the pollen season (Evaluation 3). Serum eotaxin levels were simultaneously measured in 59 healthy people from the control group. Changes in serum eotaxin levels were assessed in the healthy and allergic groups. Clinical symptoms of IgE-mediated rhinoconjunctivitis were evaluated and compared with serum eotaxin concentration changes.

Results: Mean values of eotaxin concentrations in serum during Evaluations 0-3 did not significantly differ in the healthy subjects and the patients with IgE-mediated rhinoconjunctivitis (P > 0.05). Moreover, no statistically significant differences in the serum eotaxin levels between the visits were observed in the patients who received immunotherapy (P > 0.05); however, immediately after immunotherapy (Evaluation 1) the mean serum level of eotaxin was lowest and closest to the serum eotaxin concentration in the control group at the same visit. No significant correlation between the mean value of the serum eotaxin level in the height of pollen season (r = -0.12, P > 0.05) or mean changes of the eotaxin levels between Evaluations 2 and 1 (r = -0.03, P > 0.05), on the one hand, and the cumulative score of symptoms and drug, on the other, were found.

Conclusions: The results allow to conclude that although eotaxin plays a significant role in the mechanism of antigen-specific immunotherapy, its serum expression remains a poor marker of SIT efficacy.