title: Laboratory evaluation of anti-phospholipid syndrome: a preliminary prospective study of phosphatidylserine/prothrombin antibodies in an at-risk patient cohort.
abstract: Immunoglobulin (Ig)G/IgM autoantibodies to phosphatidylserine/prothrombin (aPS/PT) were evaluated individually and in combination with criteria anti-phospholipid (aPL) tests in a prospectively ascertained cohort of patients at risk for anti-phospholipid syndrome (APS). One hundred and sixty (160) consecutive requests for lupus anti-coagulant (LAC) from the University of Utah Health Sciences Center were identified during 8 weeks. Of these, 104 unique patients had additional requests for cardiolipin (aCL) and/or beta2 glycoprotein I (aβ2 GPI) IgG and/or IgM; samples were retained and analysed for aPS/PT, aCL and/or aβ2 GPI IgG and IgM antibodies. Following testing, a comprehensive chart review was performed and patients categorized according to their clinical diagnosis. Individual and combined sensitivities, specificities, odd ratios (OR), diagnostic accuracy for specific tests or combinations by receiver operating characteristic (ROC), area under the curve (AUC) analyses and correlations between test results were determined. The sensitivities of aPS/PT IgG/IgM (54·6/45·5%) were lower than LAC (81·8%) but higher relative to aCL IgG/IgM (27·3/0%) or aβ2 GPI IgG/IgM (27·3/0%). The best correlation between LAC and any aPL test was observed with aPS/PT (P = 0·002). There was no significant difference in the diagnostic accuracies for any panel with LAC: LAC/aβ2 GPI IgG/aCL IgG [AUC 0·979, OR 475·4, 95% confidence interval (CI) 23·1-9056·5, P = 0·0001 and LAC/aβ2 GPI IgG/aPS/PT IgG or LAC/aPS/PT IgG/aCL IgG (AUC 0·962, OR 265·3, 14·2-4958·2, P = 0·0001). The high correlation between LAC and aPS/PT IgG/IgM in this preliminary study suggest that this marker may be useful in the evaluation of APS. More studies to determine the optimal aPL antibody tests combination are needed.
authors.affiliation: Associated Regional and University Pathologists (ARUP) Institute for Clinical and Experimental Pathology, Salt Lake City, UT, USA; Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA.
authors.forename: N M
authors.initials: NM
authors.lastname: Heikal
authors.forename: T D
authors.initials: TD
authors.lastname: Jaskowski
authors.forename: E
authors.initials: E
authors.lastname: Malmberg
authors.forename: G
authors.initials: G
authors.lastname: Lakos
authors.forename: D W
authors.initials: DW
authors.lastname: Branch
authors.forename: A E
authors.initials: AE
authors.lastname: Tebo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017153:Antibodies, Anticardiolipin / Q000097:blood / Q000276:immunology*; D016736:Antiphospholipid Syndrome / Q000097:blood / Q000175:diagnosis* / Q000276:immunology*; D015415:Biomarkers / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007075:Immunoglobulin M / Q000097:blood / Q000276:immunology; D016682:Lupus Coagulation Inhibitor / Q000097:blood / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010718:Phosphatidylserines / Q000276:immunology*; D011446:Prospective Studies; D011516:Prothrombin / Q000276:immunology*; D053482:beta 2-Glycoprotein I / Q000276:immunology
chemical_list: D017153:Antibodies, Anticardiolipin; D015415:Biomarkers; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D016682:Lupus Coagulation Inhibitor; D010718:Phosphatidylserines; D053482:beta 2-Glycoprotein I; D011516:Prothrombin
keywords: ELISA; anti-phospholipid antibodies; anti-phospholipid syndrome