FLOW CYTOMETRIC MONITORING OF ALLERGEN-INDUCED BASOPHIL ACTIVATION

Human basophils express many clustered differentiation antigens (CD), including CD45; however, none are specific for these cells, In a previ ous study, we described a two-color immunofluorescence procedure, empl oying antibodies to CD45 and IgE for the cytometric evaluation of baso phils. in the present work, we show that when sensitized basophils are stimulated by allergenic preparations, they demonstrate an upregulati on of CD45 as well as a decrease in anti-IgE binding, Since CD45 antig en modulation was observed with all aeroallergens tested and the decre ase in IgE expression varied with allergenic preparations, the measure ment of CD45 upregulation was used to evaluate basophil activation. Us ing this approach, reproducible results were observed when atopic pati ents were tested at different time intervals. In addition, we show tha t the upregulation of CD45 on allergen stimulated basophils is a very rapid phenomenon that is observed after a few minutes and that this ra pid flow cytometric method can also be used for investigations on nona llergenic mediators of basophil stimulation such as calcium ionophores . (C) 1995 Wiley-Liss, Inc.