Sublingual immunotherapy: a double-blind, placebo-controlled trial with Parietaria judaica extract standardized in mass units in patients with rhinoconjunctivitis, asthma, or both

Background: New routes of administering immunotherapy in respiratory allerg y are being studied as an alternative to conventional injective immunothera py. We carried out a study to evaluate the clinical efficacy and effects of sublingual immunotherapy in patients with Parietaria judaica-induced respi ratory allergy. Methods: A double-blind, placebo-controlled design was followed. Thirty pat ients with P. judaica rhinoconjunctivitis, mild asthma, or both were random ly chosen for sublingual immunotherapy (14 patients) or placebo treatment ( 16 patients). The patients underwent preseasonal rush induction treatment f ollowed by coseasonal maintenance treatment during the Parietaria pollen se ason. Symptom and drug scores, as well as specific IgE and specific lgG4, w ere recorded. Results: Significantly lower symptom and drug scores were found (P=0.04), e specially during the Parietaria pollination period, in the immunotherapy gr oup. No significant difference in specific IgE and specific IgG4 was detect ed between the active and placebo groups; a statistically significant incre ase of specific IgE was detected in both groups (P=0.05). No patient underg oing active sublingual immunotherapy reported local or systemic side-effect s. Conclusions: Our data suggest that sublingual immunotherapy is both clinica lly effective and safe in treating patients with Parietaria-induced rhinoco njunctivitis and mild asthma.