title: Granulocyte-associated IgG in neutropenic disorders.
abstract: We applied a radiolabeled antiglobulin test to a study of patients with a variety of neutropenic disorders. After defining the nature of the interaction of radiolabeled anti-IgG with the neutrophil, we studied 16 patients with neutropenia of uncertain etiology and adequate bone marrow granulocyte precursors. Twelve of these 16 patients had increased neutrophil-associated IgG (PMN-IgG). Patients with the highest levels of PMN-IgG had the lowest neutrophil counts. The majority of patients with neutropenia and increased PMN-IgG had an underlying immunologic disorder that included immune thrombocytopenic purpura in 5 patients and autoimmune hemolytic anemia in 1 patient. In some patients, elevated PMN-IgG preceded other evidence for immunologic disease. The direct antiglobulin test helped to distinguish neutropenic patients with increased PMN-IgG both from patients with neutropenia due to a known nonimmune disorder and from nonneutropenic patients with rheumatoid arthritis or systemic lupus erythematosis. Each of four patients with increased neutrophil-associated IgG treated with systemic corticosteroids responded clinically with an associated fall in neutrophil IgG and a rise in the circulating neutrophil count. The radiolabeled antiglobulin test appears useful in defining a subpopulation of patients with neutropenia due to an underlying immunologic disorder.
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D000380:Agranulocytosis / Q000276:immunology*; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D005260:Female; D006098:Granulocytes / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis* / Q000276:immunology; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D009503:Neutropenia / Q000188:drug therapy / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology
chemical_list: D000305:Adrenal Cortex Hormones; D000888:Antibodies, Anti-Idiotypic; D007074:Immunoglobulin G; D007457:Iodine Radioisotopes