Serum levels of neutrophil and eosinophil chemotactic activities in mastocytosis.

Neutrophil and eosinophil chemotactic activities (NCA and ECA) were measured in serum from twenty-two patients with urticaria pigmentosa or systemic mastocytosis. NCA was also measured after heating serum to 56 degrees C (heat-stable NCA). Although these factors were increased in about half of the patients there was no correlation with histamine release as estimated by the excretion of the main histamine metabolite methylimidazoleacetic acid (MelmAA) in urine. A significant increase in heat-stable NCA, however, was found in patients with pruritus and abnormal high values of MelmAA. It is concluded that only heat-stable NCA is a specific mast cell mediator, but that the heat-labile NCA and ECA are dependent on mast cells for their production by a different cell, tentatively identified as the macrophage.