Nasal ECP patterns and specific immunotherapy in mite-allergic rhinitis patients.

Background: Specific immunotherapy (SIT) is an effective treatment in allergic rhinitis and it has been shown to decrease nasal ECP rise after allergen challenge. Aims: To evaluate if the kynetics of nasal ECP release after specific nasal challenge could be changed by SIT and if these changes were related to the dose of allergen administered. Material and Methods: 75 allergic rhinitis patients, monosensitized to house dust mites were included: 25 controls and 50 SIT-treated patients. These patients were divided in two groups: one receiving a high dose of the allergenic extract (Group 2) and other receiving a lower dose (Group 1). Nasal challenges were performed at the beginning of the study (TO), after 6 (T1) and after 12 months (T2). Nasal ECP values were measured in nasal lavages before challenge and one and four hours after obtaining a positive reaction. Patients were also asked in every visit to evaluate on a visual analog scale the intensity of their disease in the previous month. Results: SIT was effective in improving subjective (visual analog scale) and objective parameters (nasal allergenic reactivity). Both SIT groups had significant differences between TO and T2 values and comparing with control patients. SIT reduced significantly mean post-provocation ECP values in both groups and reduced the number of patients that showed increase in nasal ECP >100% of basal values in each of the SIT-treated groups. The changes in nasal ECP values and particularly in nasal ECP patterns were more pronounced in Group 2 than in Group 1 but the differences did not reach statistical significance. Conclusions: SIT can inhibit nasal ECP increase after allergen challenge, frequently present in non SIT-treated patients. This effect is more pronounced and reaches statistical significance earlier in patients receiving higher doses of the allergenic extract used in SIT.