Fraunhofer Allergen Challenge Chambers

Allergen challenge chambers (ACCs) are an excellent tool for testing allergy treatments in early-phase clinical trials. Their particular advantages are controlled temperature, humidity and, especially, allergen concentrations that improve signal-to-noise ratios. They therefore greatly reduce the number of participants needed to demonstrate significant treatment effects compared to standard field studies. Numerous clinical trials have successfully used ACCs to test allergy treatments.


Three special challenge chambers


Fraunhofer ITEM is equipped with three special challenge chambers in which pollen and other allergens can be dispersed in the air under controlled conditions. These chambers, known as Fraunhofer Allergen Challenge Chambers (or Fraunhofer ACCs for short), each are 47 square meters in size. Only a few others like them exist anywhere in the world. The Fraunhofer ACC model was validated for natural grass pollen in 2001 and for natural birch pollen in 2014. It has been used in numerous clinical trials to test the efficacy, duration, and onset of action of allergy treatments.

Process patent

In 2008, Fraunhofer ITEM patented a process in which a commercially available allergen solution is mixed with lactose. The resulting solution is spray-dried to create particles of a defined size, which are then dispersed in a Fraunhofer ACC. This approach makes it possible to use the Fraunhofer ACC to test treatments for a wide range of allergens, including some that are difficult to aerosolize, such as cat allergen and house dust mite. In addition, the ability to define the particle size permits targeted challenging of the nose or lungs.

Use of the Fraunhofer ACC is not limited to testing allergy treatments; it is also an excellent means of studying how allergic rhinitis symptoms affect the absorption of intranasal drug formulations by combining ACC exposures with pharmacokinetic studies.

The advantages of the Fraunhofer ACC


  • It is an excellent tool for testing new allergy treatments in early-phase clinical trials with a relevant clinical endpoint, e.g. nasal symptoms
  • Studies can be performed year-round, eliminating the need to wait for the right pollen season to start
  • Small samples are sufficient, due to the controlled atmosphere and stable pollen count
  • Objective parameters such as nasal flow (rhinomanometry) and the volume of nasal secretions can be easily assessed
  • The onset and duration of action can be assessed
  • Biomarkers (cells and cytokines) can be assessed by nasal lavage and nasal secretions in our state-of-the-art immunology lab
  • Pharmacokinetic studies for studying how nasal inflammation influences drug absorption
  • 100% patient compliance
  • Other challenges (ozone, endotoxins, methacholine, mannitol, particles)


Prof. Dr. med. Jens Hohlfeld
Fraunhofer ITEM
Division Director
Phone +49 511 5350-8101
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Dr. med. Dipl.-Kfm. Philipp Badorrek
Fraunhofer ITEM
Head of Department
Phone +49 511 5350-8130
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