CARNOYS FIXATIVE REDUCES THE NUMBER OF CHYMASE-POSITIVE CELLS IN IMMUNOCYTOCHEMICAL STAINING OF CORD-BLOOD-DERIVED HUMAN CULTURED MAST-CELLS

KleinJan et al. (Allergy 1996;51:614-20) reported that Carnoy's fixati ve reduced the number of chymase-positive mast cells in the nasal muco sa, Therefore, in the present study, we investigated whether Carnoy's fixative reduces the number of chymase-positive cells from cord-blood- derived human cultured mast cells when compared with other types of fi xatives. Human mast cells were obtained by culturing cord-blood-derive d CD34-positive cells in the presence of stem cell factor and interleu kin-6. Staining procedures of the cells in fixation with Carnoy's fixa tive and with other fixatives gave no differences among the number of tryptase-positive cells, whereas fixation with Carnoy's fixative for 1 5 min gave a significant decrease in the number of chymase-positive ce lls compared with acetone for 10 min. The number of chymase-positive c ells decreased in a time-dependent manner under fixation with Carnoy's fixative, indicating that Carnoy's fixative had a negative effect on the number of chymase-positive cells from cord-blood-derived human cul tured mast cells.