The purpose of this study is to evaluate the clinical efficacy and mucosal/systemic antibody response changes after SLIT using house dust mite allergen with or without bacterial extracts in mite-allergic children.

Patients with allergic rhinitis with or without asthma were selected for a randomized double-blind, placebo-controlled trial and distributed into three groups: DPT (Dpt allergen extract, n=34), DPT+MRB (Dpt allergen plus mixed respiratory bacterial extracts, n=36), and Placebo (n=32). Clinical evaluation and immunological analyses are being carried out before and after 12 and 18 months of treatment, including rhinitis/asthma symptom and medication scores, skin prick test (SPT) to Dpt, and measurements of Dpt-, Der p 1-, Der p 2-specific serum IgE, IgG4, IgG1 and -specific salivary IgA.

Inclusion Criteria:

• Clinical diagnosis of allergic rhinitis
• Positive skin test to Dermatophagoides pteronyssinus total extract
• Positive serum levels of specific IgE to D. pteronyssinus extract

Exclusion Criteria:

• Previous allergen immunotherapy
• Use of antihistamines 1 week or topical corticosteroid up to 3 weeks prior to skin prick test
• Long term use of systemic corticosteroid.
• Airway infection 30 days prior to the selection.
• Children with severe asthma, malignant, cardiovascular or autoimmune diseases, under chemotherapy or immunosuppressor therapy.
• Users of cigarette smoke
• Presence of severe skin lesions