C5a-induced in vitro basophil activation in patients with chronic urticaria: a pilot study.
BACKGROUND
Complement component 5a (C5a) might be involved in the formation of wheals in patients with chronic urticaria (CU). We sought to compare the in vitro responsiveness of basophils to C5a in patients with CU and in a control group.


METHODS
Basophil surface expression of activation marker CD63 induced by C5a, anti-FcepsilonRI mAb or anti-IgE pAb was measured using flow cytometry in 17 patients with CU and in 10 healthy controls.


RESULTS
Patients with CU showed significantly greater basophil CD63 surface expression induced by C5a (median [interquartile range]; 16.4% [13-25.1]; P = 0.011) than the group of healthy controls (10.7% [7.2-16.8]). In contrast, basophil CD63 response to anti-IgE and anti-FcepsilonRI was lower in the CU group (12.3% [6-36.3]; 25.9% [12.5-60.5]) than in the control group (51.7% [6.7-84.3]; 62.1% [9.7-89.2]), although not statistically significant.


CONCLUSIONS
Results of this pilot study suggest that patients with CU might have an enhanced basophil response to stimulation with C5a, indicating that further studies in CU basophil responsiveness are needed.
Korosec
Peter
P
University Clinic of Respiratory and Allergic Diseases, Golnik, Slovenia. peter.korosec@klinika-golnik.si
Subic
Tjasa
T
Adamic
Katja
K
Silar
Mira
M
Kosnik
Mitja
M
D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000276:immunology*; D015549:Basophil Degranulation Test; D001491:Basophils / Q000276:immunology*; D002908:Chronic Disease; D015936:Complement C5a / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D010980:Platelet Membrane Glycoproteins / Q000276:immunology*; D017455:Receptors, IgE / Q000276:immunology; D060149:Tetraspanin 30; D014581:Urticaria / Q000276:immunology*
D015703:Antigens, CD; C554586:CD63 protein, human; C543355:FcepsilonRI alpha-chain, human; D010980:Platelet Membrane Glycoproteins; D017455:Receptors, IgE; D060149:Tetraspanin 30; D007073:Immunoglobulin E; D015936:Complement C5a