Inclusion Criteria:  Participation in the predecessor study including complete intake of the holo-BLG lozenge for 3 months; inclusion in the final analysis set of the predecessor study patients with allergic rhinoconjunctivitis caused by house dust mites of any gender, aged 18-65 years Verbal and written informed consent  Exclusion Criteria:  Persons <18 years lack of verbal and written consent persons who do not speak German seriously ill persons Persons with immunosuppressive medication such as systemic corticosteroids, cyclosporine Pregnancy and breastfeeding psychiatric illness Persons who have received or have started sublingual or subcutaneous immunotherapy (SLIT/SCIT) against house dust mites in the last 2 years before screening Contraindications and/or history of adrenaline intolerance and/or emergency medication. Concurrent use of anti-allergic medications and/or inadequate washout period of these anti-allergic medications prior to the selection process and exposure in the exposure chamber Use of an investigational drug 30 days/5 half-lives of the drug (whichever is longer) prior to screening Use of certain drugs prior to V5: Systemic corticosteroids within 3 weeks; Topical nasal corticosteroids within 2 weeks; Chromones within 7 days; Antihistamines within 72h; Antibiotics within 3 months; Pro-, Pre- and Synbiotics 1 month