Antibodies to Actin in Autoimmune Neutropenia
WALTER REED ARMY INST OF RESEARCH WASHINGTON DC DIV OF MEDICINE
Pagination or Media Count:
In an effort to characterize the cellular antigens recognized by anti-neutrophil antibodies in autoimmune neutropenia, we studied sera, purified immunoglobulin G IgG and isolated Fab2 from 70 neutropenic patients suspected of this diagnosis. Anti-neutrophil antibodies were found in the sera of 36 of these patients by either 125 I-staph A binding or immunofluorescence cytometric techniques that detected increased binding of patients IgG to normal neutrophils. Anti-neutrophil antibody positive sera were then evaluated for specific binding to electrophoretically separated neutrophil membrane-associated proteins by immunoblotting. A 43-Kd protein was consistently identified by eight anti-neutrophil antibody positive sera. The specificity of binding to this protein was confirmed with affinity purified IgG and Fab2 fragments prepared from these sera. Sera from 20 healthy normal controls and from 22 non- neutropenic, anti-neutrophil antibody negative rheumatoid arthritis patients failed to bind this protein.