The patient serum and donor basophils are incubated for 60 min. at 37°C. Histamine release is measured from stimulated and unstimulated cells and the results are expressed as histamine e release in percentage of the total histamine content.
A histamine release > 16,5% is a positive test result in both children and adult patients (4,5).
Why test for autoreactive urticaria?
- Patients will know where their disease is coming from and they don’t have to worry about things like food etc.
- Physicians know that these patients are hard to treat because they need more antihistamines to achieve the same levels of symptom control.
- Patients may have their disease for a longer duration of time. Patients show more commonly other autoimmune disorders and should be checked for autoantibodies
TESTING FOR CHRONIC SPONTANEOUS URTICARIA
It is generally accepted that the Autologous Skin Serum Test (ASST) tests the reactivity of mast cells to serological histamine releasing factors that causes a wheal and flare reaction in the skin.
However, the outcome of ASST has been proven to be highly dependent on the experience and subjective assessment of the performing doctor or nurse, and as serological factors other than auto-antibodies can also cause a wheal and flare reaction in the skin, a positive ASST test is suggestive but not confirmative of an autoimmune reaction.
Functionality of auto-antibodies can however be tested by the in vitro based serum induced basophil histamine release test (HR-Urticaria test), in which serum from the CSU patient is incubated with healthy donor PBMCs containing 1 to 2 % basophils, and the resulting histamine release is measured (1).
The concordance between ASST and HR-Urticaria test is about 70 % (1,2) and a positive HR-Urticaria Test has furthermore been shown to be a marker for ciclosporin-responsiveness in patients with chronic spontaneous urticaria.