title: Autoantibodies to a novel early endosome antigen 1.
abstract: Autoantibodies to EEA1, an antigen on early endosomes, were first reported in the serum of a patient with subacute cutaneous lupus erythematosus (SCLE). Here we have examined 38 sera selected for investigation of autoantibodies to EEA1 on the basis of cytoplasmic vesicle-like reactivity by immunofluorescence. Ten of the sera were reactive to a HeLa cell protein of approximately the same M(r) as human EEA1. Eight of these sera belonged to the IgG1 subclass. Five of the sera reacted with fusion proteins incorporating either the amino (from amino acids 1 to 209) or the carboxyl (incorporating the most C-terminal 300 amino acids) terminus of the human EEA1 protein. Antigens reactive with these 5 sera colocalized with internalized transferrin receptors, indicating their association with early endosomes. The other 5 sera which did not react to both fusion proteins did not colocalize with internalized transferrin receptors. We conclude that 5 of the 38 patients (13%) have autoantibodies to EEA1. None of these patients have SCLE, but have generalized joint pain, polyarthritis, rheumatoid arthritis, or circulating rheumatoid factors.
authors.affiliation: Department of Pathology and Immunology, Monash Medical School, Prahran, Victoria, Australia.
authors.forename: R L
authors.initials: RL
authors.lastname: Waite
authors.forename: J W
authors.initials: JW
authors.lastname: Sentry
authors.forename: H
authors.initials: H
authors.lastname: Stenmark
authors.forename: B H
authors.initials: BH
authors.lastname: Toh
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000918:Antibody Specificity; D018771:Arthralgia / Q000097:blood / Q000276:immunology; D001168:Arthritis / Q000097:blood / Q000276:immunology; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000276:immunology; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D001327:Autoimmune Diseases / Q000097:blood / Q000276:immunology*; D015415:Biomarkers; D011992:Endosomes / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006367:HeLa Cells; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007075:Immunoglobulin M / Q000097:blood / Q000276:immunology; D007592:Joint Diseases / Q000097:blood / Q000276:immunology*; D008297:Male; D008565:Membrane Proteins / Q000276:immunology*; D011990:Receptors, Transferrin / Q000032:analysis; D011993:Recombinant Fusion Proteins / Q000276:immunology; D012217:Rheumatoid Factor / Q000032:analysis; D033921:Vesicular Transport Proteins
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008565:Membrane Proteins; D011990:Receptors, Transferrin; D011993:Recombinant Fusion Proteins; D033921:Vesicular Transport Proteins; C093846:early endosome antigen 1; D012217:Rheumatoid Factor