Demonstration of drug-dependent antibodies in two patients with neutrophenia and successful treatment with granulocyte-colony-stimulating factor

BACKGROUND: Many drugs have been reported as being capable of inducing immune neutropenia, but the causative drug-dependent antibodies were rarely demonstrated. STUDY DESIGN AND METHODS: This report describes the results of serologic testing and treatment in two children with immune neutropenia related to cefotaxime and metamizole, respectively. Serum samples were tested in the presence and the absence of the drugs using the granulocyte agglutination test (GAT), the granulocyte immunofluorescence test (GIFT), and the monoclonal antibody-specific immobilization of granulocyte antigens (MAIGA) assay. RESULTS: The serum of one child contained cefotaxime-dependent antibodies that were detectable by the GAT and the MAIGA assay, but not by the GIFT. The serum of the other child gave positive reactions in the GAT and GIFT due to HLA antibodies and in the MAIGA assay only in the presence of metamizole. While cefotaxime-dependent antibody was directed against CD16, the metamizole antibody was directed against CD11b and CD35. The administration of granulocyte-colony-stimulating factor led to an abrupt increase in circulating neutrophils in both cases. CONCLUSION: The use of more than one technique is necessary for detection of drug-dependent antibodies against neutrophils, and early administration of granulocyte-colony-stimulating factor may result in fewer complications in these patients.