title: Prevalence of circulating immune complexes in patients with cystic fibrosis and arthritis.
abstract: We report the clinical and laboratory characteristics of eight patients with cystic fibrosis (CF) and arthropathy. Five patients had frequently relapsing, episodic arthritis; one had chronic arthritis with high titers of rheumatoid factors that could not be distinguished from juvenile chronic arthritis. In two patients the arthropathy did not relapse. Forty-six patients with CF but without arthropathy, seen during the same 1-year period, served as control subjects. Results of lung function tests and sputum cultures were similar in both groups. The sera of six of the eight patients with CF-arthropathy had high levels of circulating immune complexes, measured both by C1q-binding and the indirect granulocyte phagocytosis test, whereas only 1 of 12 control patients tested had positive C1q binding (p < 0.023). Serum complement levels were normal in both groups. Synovial biopsies, performed in three patients, showed only scanty lymphocytic infiltrates; immunofluorescent staining showed deposits of IgM, IgG, and components of complement C1q, C3, and C4. These findings suggest that the arthropathy found in CF is an immune-mediated phenomenon.
authors.affiliation: Department of Immunology, University Hospital for Children, Utrecht, The Netherlands.
authors.forename: N M
authors.initials: NM
authors.lastname: Wulffraat
authors.forename: E R
authors.initials: ER
authors.lastname: de Graeff-Meeder
authors.forename: G T
authors.initials: GT
authors.lastname: Rijkers
authors.forename: H
authors.initials: H
authors.lastname: van der Laag
authors.forename: W
authors.initials: W
authors.lastname: Kuis
mesh_terms: D000293:Adolescent; D000328:Adult; D000936:Antigen-Antibody Complex / Q000097:blood*; D001168:Arthritis / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D015922:Complement C1q / Q000032:analysis; D003550:Cystic Fibrosis / Q000276:immunology* / Q000503:physiopathology; D005260:Female; D005455:Fluorescent Antibody Technique; D005500:Follow-Up Studies; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007223:Infant; D008168:Lung / Q000503:physiopathology; D008297:Male; D015995:Prevalence; D012008:Recurrence; D012189:Retrospective Studies; D012217:Rheumatoid Factor / Q000097:blood; D013583:Synovial Membrane / Q000276:immunology / Q000473:pathology
chemical_list: D000936:Antigen-Antibody Complex; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D015922:Complement C1q; D012217:Rheumatoid Factor