title: Immune complex processing in patients with systemic lupus erythematosus. In vivo imaging and clearance studies.
abstract: Abnormal processing of immune complexes (IC) may be important in the pathogenesis of systemic lupus erythematosus (SLE). The clearance of large soluble IC (comprising hepatitis B surface antigen (HBsAg)/anti-HBsAg) radiolabeled with 123I was examined in 12 normal subjects and 10 patients with SLE. IC localization was analyzed by static and dynamic gamma-scintigraphy. Initial IC clearance from blood was more rapid in patients (median t1/2 = 2.15 min) than normals (median t1/2 = 5.15 min) due to more rapid uptake in the liver. However, in the SLE group, up to 12% of complexes were released from the liver after 30-50 min. Splenic uptake of immune complexes was reduced in the patients and there was reduced ability to retain IC in this organ. Plasma complement levels and erythrocyte complement receptor type 1 numbers were reduced in the patients, resulting in defective opsonization of IC and reduced red cell binding in vivo. These observations support the hypothesis that IC handling is abnormal in SLE.
authors.affiliation: Rheumatology Unit, Hammersmith Hospital, London, United Kingdom.
authors.forename: K A
authors.initials: KA
authors.lastname: Davies
authors.forename: A M
authors.initials: AM
authors.lastname: Peters
authors.forename: H L
authors.initials: HL
authors.lastname: Beynon
authors.forename: M J
authors.initials: MJ
authors.lastname: Walport
mesh_terms: D000328:Adult; D000936:Antigen-Antibody Complex / Q000378:metabolism*; D005260:Female; D006514:Hepatitis B Surface Antigens / Q000378:metabolism; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D017463:Receptors, Complement 3b / Q000032:analysis; D013154:Spleen / Q000378:metabolism
chemical_list: D000936:Antigen-Antibody Complex; D006514:Hepatitis B Surface Antigens; D017463:Receptors, Complement 3b