FIBRIN FORMATION DURING ONGOING CUTANEOUS ALLERGIC REACTIONS - COMPARISON OF RESPONSES TO ANTIGEN AND CODEINE

Background: Fibrin formation, assessed by fibrinopeptide A levels, was evaluated over a 5-hour period al skin chamber sites challenged conti nuously with pollen antigen or codeine in 10 reactive individuals. Met hods: The levels of fibrinopeptide A at antigen sites were compared wi th those at sites challenged with buffer diluent alone or with codeine for the first 3 hours, followed by antigen challenge during the subse quent 2 hours. Results: Findings showed: (1) fibrinopeptide A levels w ere higher at antigen challenge sites than at codeine challenge sites by the third hour, with these levels at both sites greater than those at buffer sites; (2) antigen challenge of the previous codeine sites d uring the third to fifth hours led to a further increase in fibrinopep tide A levels; (3) fibrinopeptide A levels correlated with chamber flu id immunoglobulin G levels but not with chamber fluid histamine levels . Conclusions: Because antigen and codeine both activate mast cells pr ominently, these findings suggest that other factors play a role in th e persistent fibrin formation at allergic skin reaction sites. Because antigen activates both basophils and mast cells and codeine only acti vates mast cells, we conclude that both basophils and mast cells contr ibute to the persistent fibrin formation at sites of allergic reaction s.