Prostaglandin D2 release from human skin mast cells in response to ionophore A23187

1. Cells were dispersed from human foreskin by proteolytic digestion and enriched or depleted in mast cell content by density gradient flotation on discontinuous gradients of Percoll. 2. Cells were harvested at six interfaces on the density gradient. Mast cell purity ranged from 0.6-85.0%, compared to 5.5% in the unfractionated cells. 3. Challenge of the cells with the calcium ionophore A23187 resulted in release of both histamine and prostaglandin D2 (PGD2). In fractions depleted of mast cells, histamine release and net PGD2 generation were low, but increasing amounts of these mediators were released as mast cell purity was increased up to 59%. 4. Overall, there was a significant correlation between the net generation of PGD2 and histamine (r = 0.9234, P less than 0.001) and also between PGD2 release and mast cell number (r = 0.7475, P less than 0.001). 5. These data provide the first direct evidence of the capacity of the human cutaneous mast cell to synthesize and release PGD2.