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Serum‐induced basophil CD63 expression by means of a tricolour flow cytometric method for the in vitro diagnosis of chronic urticaria
Author(s) -
Frezzolini A.,
Provini A.,
Teofoli P.,
Pomponi D.,
De Pità O.
Publication year - 2006
Publication title -
allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.363
H-Index - 173
eISSN - 1398-9995
pISSN - 0105-4538
DOI - 10.1111/j.1398-9995.2006.01033.x
Subject(s) - cd63 , basophil activation , basophil , medicine , immunology , flow cytometry , immunoglobulin e , whole blood , antibody , autoantibody , population , biology , microrna , biochemistry , environmental health , microvesicles , gene
Background: Functional autoantibodies against the α ‐chain of the high‐affinity IgE receptor (Fc ɛ RI α ) identify a subset of patients with chronic urticaria (CU) due to autoreactivity, as assessed by an in vivo positive response to autologous serum skin test (ASST). We performed a study to standardize the serum‐induced basophil activation assay by flow cytometry (FCM) using a new tricolour method, assessing the diagnostic performance of this test in discriminating between ASST+ and ASST− CU patients. Methods: Sera of 64 CU patients (22 ASST+ CU and 42 ASST− CU) and 10 healthy subjects were tested for their ability to induce basophil CD63 expression when incubated with whole blood of both atopic (D A ) and non‐atopic donors (D NA ). Using a triple‐labelled strategy with anti‐CD123, anti‐HLA‐DR and anti‐CD63 antibodies, CD63+ basophils were identified on a selected population of CD123+ HLA‐DR‐ cells. In 3 ASST+ CU patients who underwent cyclosporine therapy, the assay was performed before and after treatment. Results: The ASST+ CU sera resulted in a significant higher induction of basophil CD63 expression compared with ASST− CU and healthy donors sera; when whole blood from D A was used, sensitivity and specificity of the assay were 95.5% and 90.5% respectively. ASST+ CU serum activity was significantly decreased during cyclosporine A treatment, in parallel with clinical remission. Conclusions: Chronic urticaria serum‐induced CD63 expression assay performed on D A whole blood by means of our tricolour FCM method could be the most useful tool for identification of a subset of patients with autoimmune CU and may become a promising tool also for monitoring treatment efficacy.