LONG-TERM FOLLOW-UP OF NASAL IMMUNOTHERAPY TO PARIETARIA - CLINICAL AND LOCAL IMMUNOLOGICAL EFFECTS

Background Local nasal immunotherapy (LNIT) with extracts in powder ha s been demonstrated clinically effective and devoid of side-effects in several controlled trials; nevertheless, no data concerning the long- term effects of LNIT are presently available. Methods In a recent doub le-blind, placebo-controlled study of LNIT to Parietaria pollen we obs erved, by means of specific nasal provocation test (SNPT) that LNIT is able to modify the local allergic inflammatory response. In the prese nt study we followed up the same patients in open fashion for 2 furthe r years.Results The results confirmed the clinical efficacy of LNIT an d showed that it is strictly dependent on pre-seasonal administration: in fact, after LNIT discontinuation a clinical relapse was observed. A certain long-lasting protective effect on SNPT parameters (nasal sym ptoms and neutrophils infiltration) was also observed, whereas an incr ease of eosinophils count and ICAM-1 expression on nasal epithelial ce lls appeared as possible markers of clinical relapse. Conclusion The p resent study suggests that pre-seasonal LNIT can be taken in considera tion in selected subjects as prophylactic treatment for pollen-induced rhinitis. In addition, the results obtained provide informations abou t the duration of clinical efficacy and add data about the local aller gic inflammation and its modulation.