Murine and human hematopoietic colony formation:: A possible regulatory role for intracellular histamine

increasing number of data suggests that locally produced histamine is involved in regulation of hematopoiesis. In this study the granulocyte/macrophage (CFU-GM) colony formation by normal murine or human bone marrow cells, leukaemic colony formation (CFU-L) by a murine leukemia cell line (WEHI 3B), and colony formation by bone marrow cells from patients with chronic myeloid leukemia (CML) have been examined. We detected mRNA and protein expression of histidine decarboxylase (HDC), the only enzyme responsible for histamine synthesis both in normal bone marrow progenitor cells and in leukaemic progenitors. The significance of in situ generated histamine was shown on colony formation by inhibitory action of alphaFMH (blocking HDC activity, i.e. de novo histamine formation) and by N,N-dietilyi-2-{4-(phenyhnediyl)plienoxy}-ethanamine-HCI (DPPE) disturbing the interference of histamine with intracellular binding sites. These data provide further confirmation of the role of histamine in development and colony formation of bone marrow derived cells.