Detection of SH on the FcγRIIIb using the MAIGA assay. Neutrophils from a SH(+) donor were tested with the anti–SH-containing serum no. 1 for antibodies to FcγRIIIb, FcγRII, the subunits of the leukocyte adhesion molecule CD11b/CD18, and the C3b complement receptor CR1 (CD35).