Cellular Allergy

Where specific IgE fails to demonstrate absolute diagnostic reliability, especially in more complex reactions such as drug, venom or food allergies BÜHLMANN has the solution -       The complete Cellular Allergy diagnostics package. Flow CAST^®, the routine friendly flow cytometry test, together with BÜHLMANN high quality allergens, are the obvious additions to sIgE and the unique tool for non-IgE mediated drug allergy diagnosis.

Identification of allergens causing immediate type reactions can be a very difficult task for allergologists. The method of investigation usually starts with the patient anamnesis followed by skin tests and blood tests. However in numerous cases the results of these tests are not sufficient, making a provocation necessary, which can bear the risk of an anaphylactic event. Choosing BÜHLMANN CAST^® assays can significantly decrease the amount of provocation tests.

We offer the BÜHLMANN CAST^® (Cellular Allergen Stimulation Test) as flow cytometric assay (Flow CAST^®) and as ELISA (CAST^® ELISA). The over 150 BÜHLMANN allergens are quality controlled, validated and standardized. Bühlmann Laboratories AG is the only company, specialized in the development and validation of cellular allergy assays plus allergens.

The most often presumed etiology of life-threatening anaphylactic reactions are food (33%), insect venoms (14%) and medications (13%). In these specific fields of allergy the BÜHLMANN CAST^® assays are at the forefront of the cellular allergy in vitro diagnosis. Especially for the diagnosis of non IgE mediated allergies like some drug allergies, the BÜHLMANN CAST^® assays reach high predictive values. See details for each allergen group below.

The BÜHLMANN CAST^® assays detect immediate type allergic reactions and hypersensitivities to suspected allergens. The Flow CAST^® is a quick (1 hour) and easy whole blood flow cytometry based Basophil Activation Test (BAT). It measures the expression of the CD63 surface marker on basophils after allergen stimulation. The CD63 is labelled with the fluorochrome fluorescein isothiocyanat in order to detect the activation of basophils. Their selection is done via CCR3, labelled with phycoerythrin as fluorochromes. The combination of only two proven and known markers allows for easy gating and evaluation of the results. In autumn 2011 BÜHLMANN will launch the third generation BAT named Flow CAST^® highsens which is based on the same principle as the previous Flow CAST. The addition is a second activation marker – CD203c – from which we expect higher specificity and sensibility for drug allergens. The second cellular allergy test we offer is the CAST^® ELISA, which measures the release of sulfidoleukotrienes produced by isolated leukocytes upon stimulation with the suspected allergen.

A series of clinical studies demonstrate the importance of BÜHLMANN CAST^® tests as indispensable in a diagnostic work up in significant and specific fields of allergy:

Drugs: Multicentric studies on beta-Lactam antibiotics and NSAIDs the European Network for Drug Allergy (ENDA) concluded the following: Firstly, the application of BÜHLMANN CAST^® assays reduces significantly the need for potentially dangerous and costly drug provocation tests. Secondly, the application of BÜHLMANN CAST^® assays is clearly superior to sIgE determinations.

Bee/Wasp: With 91% of sensitivity and 95% of specificity the BÜHLMANN CAST^® assays identify the true culprit insect and support the clinical diagnosis in patients with ambiguous clinical history, skin tests or controversial sIgE. Recent studies show that the Flow CAST^® is a very useful test for detecting double positivity due to CCD and is a promising tool to follow up specific immunotherapy (SIT).

Food: The BÜHLMANN CAST^® assays are powerful tools for the discrimination and the identification of cross reactivity between clinically relevant and irrelevant IgE. Recent studies confirm the BAT as useful tool in the in vitro diagnosis of cow’s milk allergy due to its better sensitivity (91%) and specificity (90%) than sIgE (67% for both).

Food Additives: The diagnosis of food additive allergies is known to be very difficult as non immunological reactions appear to be the primary cause for the patients’ symptoms. BÜHLMANN CAST^® assays are the only valuable tools measuring these allergies by the in vitro reaction.