HUMAN HEART MAST-CELLS IN ANAPHYLAXIS AND CARDIOVASCULAR-DISEASE

All sections of human heart tissue demonstrate tryptase- and chymase-c ontaining mast cells (HHMCs) which have for the first time been isolat ed, partially purified and studied in vitro. HHMCs contain similar his tamine levels as lung and skin mast cells, but tryptase levels are low er than in skin and higher than in lung mast cells. Complement C5a cau ses rapid dose-dependent release of histamine from HHMCs, but they are refractory to substance P and fMLP. Crosslinking IgE receptors on HHM Cs leads to arachidonic acid metabolism through both the cyclooxygenas e and 5-lipoxygenase pathways. HHMCs and their vasoactive mediators ma y be involved in anaphylactic/anaphylactoid reactions in humans and in the pathogenesis of some cardiovascular diseases.