Autologous serum skin test reactions in chronic spontaneous urticaria differ from heterologous cell reactions

Background Autoimmune chronic spontaneous urticaria (CSU) is due to mast cell (MC)-activating autoantibodies, which are screened for by the autologous serum skin test (ASST) and basophil tests (BTs). Many CSU patients positive in only one of these tests. How often this occurs why currently unknown. Objectives To characterize prevalence mismatched ASST BTs patients, investigate possible reasons mismatches. Methods We determined rates ASST+/BT? ASST?/BT+ mismatches published studies. assessed sera from 48 ASST, two (basophil histamine release assay, BHRA; activation test, BAT), a MC assay (MCHRA) ex vivo microdialysis (SMD). Results The ASST/BT mismatch rate studies was 31% (ASST+/BT?: 22%, ASST?/BT+: 9%). In our ASST/BHRA ASST/BAT 35.4% (ASST+/BHRA?: 18.8% ASST?/BHRA+: 16.7%) 31.3% (ASST+/BAT?: 6.3% ASST?/BAT+: 25.0%), respectively, were significantly correlated (P = 0.0002). use heterologous MCs, vitro situ, instead basophils produced similar results (MCHRA mismatch: 47.9%, ASST+/MCHRA?: 18.8%, ASST?/MCHRA+: 29.2%; SMD 40.0%, ASST+/SMD?: 10.0% ASST?/SMD+: 30.0%), MCHRA highly with Conclusions show divergent third patients. Mismatches cannot be explained choice type cells exposed (basophils vs. cells), nor experimental setting (in situ). Thus, serum-induced whealing, seems involve signals modulating degranulation.