Malignant hematopoietic cell lines: in vitro models for the study of mast cell leukemia.

Mast cells are multifunctional hematopoietic cells producing various proinflammatory mediators. They arise in the bone marrow from CD34+ myeloid progenitors under the influence of stem cell factor but reside extravascular in the tissues. Mastocytosis which is a rare disorder encompasses a heterogeneous group of entities characterized by abnormal proliferation and accumulation of mast cells, including mast cell leukemia. Progress in understanding the (patho)biology of mast cells has been hindered by the lack of genuine model systems, such as continuous cell lines. Now the two in vitro models HMC-1 and LAD 1/2 are available. Cell line HMC-1 was published in 1988; the sister cell lines LAD 1 and LAD 2 have been established in 2000. These cell lines were all derived from patients with mast cell leukemia-sarcoma. The cell lines have been properly authenticated; their immunophenotypic, cytogenetic, molecular, and functional features have been described in detail. Taken together, these cell lines reproduce faithfully most or all of the characteristics of primary normal or malignant cells in so far as these are known. Interest in this rare but nevertheless remarkable cell type should gain momentum with the availability of model systems.