Cytochemical detection of histamine in the human granulopoietic series of healthy subjects and of patients affected by chronic myeloid leukaemia. A spectrophotofluorimetric test for checking OPT-induced fluorescence in isolated cells.

Cellular histamine in blood and bone marrow has been identified histochemically using an o-phthaldialdehyde fluorescence reaction. The specificity of the reaction was tested by a spectrofluorometric analysis of cell extracts. In normal blood, the basophils emit a bright yellow fluorescence, whereas neutrophils, eosinophils and platelets react less consistently and when they do, they give off a less intense yellow or blue emission. In normal marrow, basophils react strongly whereas the metamyelocytes and later granular cells show only a weak yellow or blue fluorescence. In chronic myeloid leukaemia, cells of the granular series emit a strong yellow fluorescence at all stages of development, although still less intense than the basophils. During remission, the fluorescence pattern of cells from leukaemic subjects reverts to that of normal cells.