The primary objective of the pilot study is to compare inflammatory responses in blood sera from patients receiving first allergen immunotherapy (AIT) with aluminium (Alum), microcrystalline tyrosine (MCT), or a combination of MCT and monophosphoryl lipid A (MPLA) as adjuvants. The AIT products are containing allergen extracts of grass and tree pollen). Blood is collected before as wells as one day, seven days, and 6-7 weeks after first AIT, and the blood is analysed for content of inflammatory proteins and antibodies.

This pilot study is an observational study with subsequent use of coded biological material. The blood sera are collected and prepared at the Allergy Units at the University Hospital Zurich (USZ) or Centre for Rhinology and Allergology Wiesbaden (AZW). The AZW serum samples will be transferred to USZ for serological analysis. The AIT patients will be allocated to three arms based on their scheduled AIT. Two arms will be allocated to patients at the USZ Allergy Unit, while the last arm is allocated to patients at AZW.

Sixteen study subjects will be recruited from allergy patients that visit the Allergy Unit at USZ to receive AIT as part of standard of care treatment for their allergy. If the patients receive AIT, they can be included in the study. The decision on performing AIT is done by the USZ allergologist, and the therapy itself is not part of the current research project. The 16 USZ patients are split in two study arms. One arm of study subject is scheduled for grass/tree AIT with aluminium-containing "Allergovit", and the second arm is scheduled to receive grass/tree AIT with MCT-containing Polvac.

Eight study subjects will be recruited from allergy patients that visit the AZW to receive AIT as part of standard of care treatment for their allergy. If the patients receive AIT, they can be included in the study. The decision on performing AIT is done by the AZW allergologist, and the therapy itself is not part of the current research project. The 8 patients comprise the third arm of the overall study, and they receive grass/tree AIT with MCT- and MPLA-containing Pollinex Quattro.

Inclusion Criteria:

• History of allergy due to IgE sensitisation to any allergen that is treatable by means of AIT, e.g. grass pollen allergens, three pollen allergens, animal dander allergens, dust mite aller-gens, or insect venom allergens.
• Scheduled to receive first AIT with Allergovit oder Polvac at USZ or to receive Pollinex Quattro at AZW.
• Signed written informed consent for subsequent use of coded blood samples including blood leukocytes data and serological data.

Exclusion Criteria:

• Previous AIT
• Chronic inflammatory diseases (rheumatic diseases, pyelonephritis, osteomyelitis or others)
• Acute infections
• Drug or alcohol abuse within the last 5 years
• Relevant anaemia (as judged by investigator)
• Blood donation within the last 30 days or during the next 7 days
• Pregnancy or breast feeding
• Systemic glucocorticoid or antihistamine therapy within the last 30 days or during the next 7 days.
• Systemic or local immune drug therapy within the last 30 days during the next 7 days.
• For linguistic and/or cognitive reasons unable to understand the study procedures

Patients that will be considered for inclusion into the study should have been scheduled for AIT by means of subcutaneous injections of Allergovit® (USZ), Polvac (USZ), or Pol-linex Quattro (AZW), the goal being to include eight patients from each of the three treatment regimens.

Important, the study subjects are only recruited among patients that are to receive their very first AIT. The AIT is not part of the study, but takes place due to prior decisions by the allergologists at USZ or at AZW.