title: Anti-52 kDa Ro, anti-60 kDa Ro, and anti-La antibody profiles in neonatal lupus.
abstract: OBJECTIVE
  Studies suggest that anti-52 kDa Ro antibodies are more sensitive and specific than anti-60 kDa Ro antibodies for neonatal lupus. However, these studies mainly used immunoblot or ELISA using recombinant protein, which have poor sensitivity for anti-60 kDa Ro antibodies. In addition, the control patients were not disease matched. We reassessed the sensitivity and specificity of anti-52 kDa Ro, anti-60 kDa Ro, and anti-La, addressing these limitations.
  
  
  RESULTS
  To assess sensitivity, 125 mothers of children with neonatal lupus (NLM) were recruited. All maternal sera were assessed using a commercial line immunoassay that uses natural 60 kDa Ro protein (Inno-Lia ANA Update, Innogenetics NV, Gent, Belgium). By this method, 96% of the sera had antibodies to 60 kDa Ro, 86% to 52 kDa Ro, and 78% to 48 kDa La. Immunoblot of 65 NLM showed significantly fewer positive results for anti-60 kDa Ro (p < 0.001) and anti-52 kDa Ro (p < 0.05). Sensitivity of the 3 antibodies was assessed in the symptomatic mothers of children with congenital heart block (CHB) (78 women) and disease matched controls with unaffected children (65 women) using Inno-Lia ANA Update. The sensitivity of each antibody was compared by multiple logistic regression to adjust for maternal disease. There was no significant difference between the groups for 60 kDa Ro or for anti-52 kDa Ro antibody. However, there was a significant difference for the anti-La antibody (p = 0.001), with an odds ratio of 3.59. This translates to an increase in risk from a published 2% for CHB in an anti-Ro-positive mother to 3.1% if the woman is also anti-La antibody-positive, and to a decrease in risk to 0.9% if anti-La-negative.
  
  
  CONCLUSIONS
  Contrary to previous reports, 52 kDa Ro as detected by Inno-Lia ANA Update is not more specific for or frequent in CHB than 60 kDa Ro. However, the presence of anti-La antibodies significantly increases the risk for CHB.
authors.affiliation: Department of Rheumatology, King's College Hospital, London SE5 9RS, UK. Patrick.Gordon@kcl.ac.uk
authors.forename: Patrick
authors.initials: P
authors.lastname: Gordon
authors.forename: Munther A
authors.initials: MA
authors.lastname: Khamashta
authors.forename: Eric
authors.initials: E
authors.lastname: Rosenthal
authors.forename: John M
authors.initials: JM
authors.lastname: Simpson
authors.forename: Gurleen
authors.initials: G
authors.lastname: Sharland
authors.forename: Antonio
authors.initials: A
authors.lastname: Brucato
authors.forename: Franco
authors.initials: F
authors.lastname: Franceschini
authors.forename: Katrien
authors.initials: K
authors.lastname: De Bosschere
authors.forename: Lydie
authors.initials: L
authors.lastname: Meheus
authors.forename: Pier Luigi
authors.initials: PL
authors.lastname: Meroni
authors.forename: Graham R V
authors.initials: GR
authors.lastname: Hughes
authors.forename: Jill
authors.initials: J
authors.lastname: Buyon
mesh_terms: D000974:Antibodies, Antinuclear / Q000032:analysis / Q000276:immunology*; D001323:Autoantibodies / Q000032:analysis*; D015415:Biomarkers / Q000032:analysis; D002675:Child, Preschool; D015331:Cohort Studies; D018450:Disease Progression; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D008180:Lupus Erythematosus, Systemic / Q000151:congenital* / Q000453:epidemiology / Q000276:immunology*; D008297:Male; D015999:Multivariate Analysis; D012016:Reference Values; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
chemical_list: D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D015415:Biomarkers; C035356:SS-A antibodies