Fibrin formation during ongoing cutaneous allergic reactions: comparison of responses to antigen and codeine

Fibrin formation, assessed by fibrinopeptide A levels, was evaluated over a 5-hour period at skin chamber sites challenged continuously with pollen antigen or codeine in 10 reactive individuals.

The levels of fibrinopeptide A at antigen sites were compared with those at sites challenged with buffer diluent alone or with codeine for the first 3 hours, followed by antigen challenge during the subsequent 2 hours.

Findings showed: (1) fibrinopeptide A levels were 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 during the third to fifth hours led to a further increase in fibrinopeptide A levels; (3) fibrinopeptide A levels correlated with chamber fluid immunoglobulin G levels but not with chamber fluid histamine levels.

Because antigen and codeine both activate mast cells prominently, these findings suggest that other factors play a role in the persistent fibrin formation at allergic skin reaction sites. Because antigen activates both basophils and mast cells and codeine only activates mast cells, we conclude that both basophils and mast cells contribute to the persistent fibrin formation at sites of allergic reactions.