title: Antineutrophil cytoplasmic antibodies: two cases of changing antigenic specificity.
abstract: The transformation of the antineutrophil cytoplasmic antibody (ANCA) specificity in the absence of specific drug treatment has not been reported in the literature. A few studies have suggested changes in the epitopes recognized by the ANCAs. We describe two patients who switched from myeloperoxidase-positive to PR3 (proteinase 3)-positive ANCA during the course of their disease process and subsequently remained unchanged. One patient developed ulcerative colitis following the appearance of PR3-ANCA while the other remains quiescent. Regular follow-up and close monitoring of ANCA specificity are essential. A change of specificity may indicate the development of a new ANCA-related disease.
authors.affiliation: Department of Immunology, Royal Preston Hospital, Lancashire Teaching Hospitals NHS Trust, Preston PR2 9HT, UK.
authors.forename: Rehana
authors.initials: R
authors.lastname: Saleem
authors.forename: Michael
authors.initials: M
authors.lastname: Oliver
authors.forename: Anthony
authors.initials: A
authors.lastname: Rowbottom
authors.forename: Laurie
authors.initials: L
authors.lastname: Solomon
mesh_terms: D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood* / Q000276:immunology; D003093:Colitis, Ulcerative / Q000097:blood* / Q000209:etiology / Q000276:immunology; D000939:Epitopes; D019084:Fluorescent Antibody Technique, Indirect; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D053146:Myeloblastin / Q000097:blood / Q000276:immunology; D009195:Peroxidase / Q000097:blood / Q000276:immunology; D014657:Vasculitis / Q000097:blood* / Q000209:etiology / Q000276:immunology
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D000939:Epitopes; D009195:Peroxidase; D053146:Myeloblastin