Abstract:

Objective To assess the relationships among the autologous serum-induced skin wheal-and-flare reaction, ex vivo serum-induced basophil histamine release, and serum levels of IgG anti-Fc RI autoantibodies in patients with chronic idiopathic urticaria （CIU）. Methods Sixty patients with CIU collected from the Renmin Hospital of Wuhan University were recruited for this study. Sera were obtained from the subjects, and ASST was performed in all of the subjects. The results of ASST were determined according to a recommended criterion described by Sabroe et al, and the positive results were further subclassified into wheal plus flare （W+F） pattern and wheal-only （W） pattern, negative results into flare-only （F） pattern and no response pattern. Enzyme linked immunosorbent assay was used to quantify the content of histamine released by autologous serum-induced basophils and serum levels of IgG anti-Fc RI autoantibodies. Results Of the 60 patients, 19（31.7%）were positive for ASST, including 16 （84.2%） presenting W+F pattern and 3 presenting W pattern; 41 were negative for ASST, including 3 （7.3%） giving F pattern and 38 giving no response pattern. The histamine release rate was significantly higher in ASST-positive patients than in ASST-negative patients （33.38% ± 9.83% vs. 4.06% ± 1.44%, t = 5.13, P < 0.01）, and was nearly twice as high as that in basophils induced by 10 μmol/L formyl-methionyleucylphenylalanine (Fmlp）. The serum levels of IgG anti-Fc RI autoantibodies were high in only patients giving （W+F） pattern （757.64 ± 168.99 ng/L）, but low in the normal human controls （43.25 ± 16.63 ng/L）. Conclusions The positive ASST result of wheal plus flare pattern is associated with high serum levels of IgG anti-Fc RI autoantibodies, and is suggestive of a clinical diagnosis of autoimmune chronic urticaria （ACU）.

Key words: diagnosis