Fucose therapy does not lead to the re-expression of the H-antigen. Isolated erythrocytes of the Bombay phenotype, from the LAD II patient before therapy and after 280 days of therapy at fucose doses of 492 mg/kg BW, and of healthy donors (as indicated) were analyzed by flow cytometry using an anti–H-antigen antibody (bold, red line) and a class-matched irrelevant control antibody (dashed, blue line). First antibody binding was detected by an FITC-conjugated rabbit antimouse IgM antibody. The secondary antibody alone is shown as dotted, black line.