title: Ribosomal P autoantibodies are present before SLE onset and are directed against non-C-terminal peptides.
abstract: Autoantibodies to ribosomal P (ribo P) are found in 15-30% of systemic lupus erythematosus (SLE) patients and are highly specific for SLE. The goal of this study is to assess the temporal association of anti-ribosomal P (anti-P) responses with SLE disease onset, as well as to characterize select humoral ribo P epitopes targeted in early, pre-diagnostic SLE samples. Patients with stored serial serum samples available prior to SLE diagnosis were identified from a military cohort. Each sample was tested for antibodies against ribo P utilizing standard C terminus ribo P enzyme-linked immunosorbent assays (ELISA) and a solid phase, bead-based assay with affinity-purified ribo P proteins. In this study, antibodies to ribo P were more common in African American SLE patients (p = 0.026), and anti-P-positive patients comprised a group with more measured autoantibody specificities than did other SLE patients (3.5 vs 2.2, p < 0.05). Antibodies against ribo P were present on average 1.7 years before SLE diagnosis and were detected an average of 1.08 years earlier in pre-diagnostic SLE samples using affinity-purified whole protein rather than C-terminal peptide alone (p = 0.0019). Furthermore, 61% of anti-P-positive patients initially had antibodies to aa 99-113, a known ribosomal P0 antigenic target, at a time point when no antibodies to the clinically used C terminus were detected. Our findings provide evidence that antibodies against ribosomal P frequently develop before clinical SLE diagnosis and are more broadly reactive than previously thought by targeting regions outside of the C terminus.
authors.affiliation: Oklahoma Medical Research Foundation, 825 N.E. 13th Street, Oklahoma City, OK 73104, USA.
authors.forename: Latisha D
authors.initials: LD
authors.lastname: Heinlen
authors.forename: Lauren L
authors.initials: LL
authors.lastname: Ritterhouse
authors.forename: Micah T
authors.initials: MT
authors.lastname: McClain
authors.forename: Michael P
authors.initials: MP
authors.lastname: Keith
authors.forename: Barbara R
authors.initials: BR
authors.lastname: Neas
authors.forename: John B
authors.initials: JB
authors.lastname: Harley
authors.forename: Judith A
authors.initials: JA
authors.lastname: James
mesh_terms: D000293:Adolescent; D000328:Adult; D001741:Black or African American; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology*; D001324:Autoantigens / Q000097:blood / Q000276:immunology*; D000939:Epitopes / Q000276:immunology*; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000175:diagnosis / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000276:immunology*; D012269:Ribosomal Proteins / Q000276:immunology*; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D000939:Epitopes; D010446:Peptide Fragments; D012269:Ribosomal Proteins
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