HUMAN MONOCYTES AND KERATINOCYTES IN CULTURE INGEST HYDROXYETHYLSTARCH

Severe itching for unknown reasons has been reported after administrat ion of hydroxyethylstarch (HES) in haemodilution therapy of humans. In skin sections from patients who had received HES for otological reaso ns HES deposition was found by immunohistochemical methods in keratino cytes, epidermal dendritic cells, endothelial cells and macrophages. T he aim of the present investigation was to study the interaction of cu ltured human monocytes and keratinocytes, normal (HNK) and malignant ( KB, A431), with FITC -conjugated HES (200/0.5). Peripheral blood monoc ytes from healthy donors were isolated by Ficoll-Hypaque gradient cent rifugation and adherence to plastic surfaces. Cells were incubated wit h HES-FITC (1 mg/ml) for 10, 20, 30, 60 and 120 min at 37-degrees-C, w ashed several times to minimize cell-associated HES-FITC. The uptake o f HES-FITC (200/0.5) was detected by fluorescence microscopy and flow cytometry. Monocytes and keratinocytes (HNK, KB, A431) acquired signif icant amounts of HES-FITC after 120 min. Endocytosis was blunted by th e addition of unconjugated HES in ten-fold concentration. At 4-degrees -C, a further inhibition was achieved, indicating an uptake of HES-FIT C by monocytes and keratinocytes in vitro. These results indicate that a connection between the storage of HES by keratinocytes and monocyte s and the observed itching in patients might be possible.