Sublingual allergoid immunotherapy: a new 4-day induction phase in patients allergic to house dust mites.

Sublingual immunotherapy with monomeric allergoid (allergoid SLIT), given according to the standard scheme, has proved effective and safe in many clinical trials. However, its build-up phase requires a long time ranging from 16 days to 14 weeks. This study therefore investigated whether, with a four-day up-dosing, the same benefit could be achieved in a shorter time. Thirty rhinitic and/or asthmatic patients (16 M and 14 F, mean age 36+/-8.2 years) allergic to house dust mites (HDM) with or without other sensitizations were randomized to allergoid SLIT or standard drug therapy. The build-up phase lasted four days. The first day the patients took a 300 AU tablet, the second day two 300 AU tablets, the third day three 300 AU tablets and the fourth day four 300 AU tablets. The total amount taken during the up-dosing was 3000 AU. Patients were then treated for 12 months at the dosage of 2000 AU/week (total amount of allergen: 104,000 AU/year). The symptom score and drug consumption were recorded from November to February on monthly diary cards. At baseline and after 12 months a Visual Analogue Scale (VAS) was used to rate the patients? well-being. Skin prick test reactivity was evaluated before and after the 12-month treatment in both groups using 10 mg/mL histamine as reference. VAS scores rose significantly (about 45%) in both groups in comparison to baseline (p=0.001). In addition, there was a significantly greater reduction of the global symptoms score (about 52%) - but not in drug consumption - in the SLIT group in comparison to controls (p=0.0004). The SLIT group showed a highly significant reduction (about 39%) in skin prick test reactivity (p=0.000003) while the control group remained unchanged (p=0.5226). No severe adverse events were observed. Even with this short four-day up-dosing, the allergoid SLIT proves to be safe. In addition, it is already effective in patients allergic to HDM after 12 months, and significantly reduces allergen-specific skin reactivity.