Cold urticaria as a model of mediator release: platelet factor 4, eosinophil cationic protein and histamine

Platelet factor 4 (PF4) has previously been linked to precipitation of cold urticaria (CU). The aim of the study was to assess the liberation of PF4, eosinophil cationic protein (ECP) and histamine after cold challenge in patients with CU. Ten controls and 8 patients with CU verified by clinical data and cold challenge test were investigated. Assessment of histamine, ECP and PF4 were done using radioimmunoassays. In patients histamine increased after 10 min on the challenged arm (NS), PF4 increase was statistically significant (p less than 0.05) both in patients and controls. ECP release showed no significant changes. Treatment with doxepin results in clinical improvement, but no changes in mediator release were seen. Thus, in contrast to previous reports an increase of PF4 was seen both in controls as well as in patients. An involvement of ECP was not ascertained. Our data suggest that neither basophils, nor eosinophils or platelets are directly involved in cold urticaria and that mast cell-dependent mediators may be of greater relevance.