Association of neutropenia in systemic lupus erythematosus (SLE) with anti-Ro and binding of an immunologically cross-reactive neutrophil membrane antigen.
SLE is associated with the production of autoantibodies to self-constituents. In particular, certain ribonucleoprotein particles are targeted. Despite the multitude of autoantibodies produced and the remarkable concentrations of these antibodies in the sera of SLE patients, there have been little data that the autoantibodies found in SLE are involved in the pathogenesis of disease or its manifestations. The present work demonstrates that anti-Ro (or SSA) is associated with granulocytopenia, binds the surface of granulocytes and fixes complement to this membrane surface. Binding is a property of anti-Ro Fab fragments and can be inhibited by 60-kD Ro. However, the antigen bound on the surface of granulocytes is a 64 000 mol. wt protein that is a novel autoantigen in SLE. As suggested by inhibition studies, sequence identity between 60-kD Ro and eight tandem repeats in the 64-kD antigen may be responsible for the observed serologic cross-reactivity. These data imply that anti-Ro antibodies that also bind the 64-kD protein mediate neutropenia in patients with SLE.
Kurien
B T
BT
Arthritis/Immunology and Cardiovascular Biology Programs, Oklahoma Medical Research Foundation, and Department of Medicine, University of Oklahoma Health Science Center, Veterans Affairs Medical Center, Oklahoma City, OK, USA.
Newland
J
J
Paczkowski
C
C
Moore
K L
KL
Scofield
R H
RH
D000328:Adult; D000974:Antibodies, Antinuclear / Q000276:immunology / Q000378:metabolism; D000954:Antigens, Surface / Q000276:immunology* / Q000378:metabolism; D001324:Autoantigens / Q000276:immunology / Q000378:metabolism*; D001666:Binding Sites, Antibody; D003429:Cross Reactions / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D006098:Granulocytes / Q000737:chemistry; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000276:immunology* / Q000378:metabolism; D008297:Male; D013058:Mass Spectrometry; D008562:Membrane Glycoproteins / Q000737:chemistry; D009503:Neutropenia / Q000276:immunology* / Q000378:metabolism; D009504:Neutrophils / Q000276:immunology* / Q000378:metabolism*; D010446:Peptide Fragments / Q000032:analysis; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins / Q000276:immunology / Q000378:metabolism*; D000099207:SS-A Antigen
D000974:Antibodies, Antinuclear; D000954:Antigens, Surface; D001324:Autoantigens; D008562:Membrane Glycoproteins; D010446:Peptide Fragments; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins; D000099207:SS-A Antigen; C116006:RO60 protein, human; C035356:SS-A antibodies