Conditioned medium from a cell strain derived from a patient with mastocytosis induces the development of mature human mast cells in vitro from normal human bone marrow.

Mature human mast cells were obtained from human bone marrow in a coculture system using conditioned medium from a human mastocytosis cell strain. These cells expressed the high-affinity IgE receptor and were tryptase, chymase and carboxypeptidase positive.