Inhibition of effects of endogenously synthesized histamine disturbs in vitro human dendritic cell differentiation.

Histamine, a principal mediator in various physiological and pathological cell functions is synthesized from L-histidine exclusively by histidine decarboxylase, an enzyme, which is expressed in many tissues of mammalian organism. Histamine plays a role in various cellular functions, including cell differentiation. The aim of this study was to determine the presence and to characterize the role of the endogenously produced histamine during in vitro dendritic cell (DC) differentiation induced by interleukin-4 (IL-4) and granulocyte-monocyte colony stimulating factor (GM-CSF).

Both interferon (IFN)alpha and IFNgamma inhibit histidine decarboxylase expression in the HT168 human melanoma cell line.

Objective: Histamine plays an important role in a series of processes including inflammation, allergy, gastric acid secretion, neurotransmission, embryogenesis and in various tumours. Histidine decarboxylase (HDC), the enzyme solely responsible for generation of histamine is expressed in many cells including regenerating and tumour cells. HDC expression is regulated by multiple tissue factors, e.