Arthritis & Rheumatism, Volume 60,
October 2009 Abstract Supplement

The 2009 ACR/ARHP Annual Scientific Meeting
Philadelphia October 16-21, 2009.

Antiphospholipid Score (aPL-S) in the Antiphospholipid Syndrome: Diagnostic Significance and Predictive Value for the Development of Thrombotic Events in Autoimmune Diseases

Otomo,  Kotaro, Atsumi,  Tatsuya, Fujieda,  Yuichiro, Kato,  Masaru, Miyamoto,  Eriko, Oku,  Kenji, Amengual,  Olga


1) To define the Antiphospholipid Score (aPL-S) by testing multiple antiphospholipid antibodies, and 2) to evaluate its efficacy for the diagnosis of antiphospholipid syndrome (APS) and predictive value for the development of thrombotic events in autoimmune diseases


1) From our database of autoimmune disease clinic, the results of antiphospholipid antibodies in 233 patients were used to define aPL-S. Five clotting assays (the mixing studies: activated partial thromboplastin time (APTT), kaolin clotting time, the dilute Russel's viper venom test (dRVVT), and the confirmatory tests: APTT and dRVVT) and 6 ELISAs (IgG/M anticardiolipin antibodies, IgG/M anti-beta2-glycoprotein I antibodies and IgG/M phosphatidylserine dependent antiprothrombin antibodies) were analyzed. The aPL-S was calculated according to the number of positive tests and their titers (range 0–83), and compared with the history of thrombosis/pregnancy morbidity. 2) For further analysis, we retrospectively explored the predictive value of aPL-S for thrombotic events. This part of the study comprised 221 patients with autoimmune diseases (12 primary APS, 16 APS with systemic lupus erythematosus and 193 other autoimmune diseases). The aPL-S in 2002 was evaluated in all subjects. Among all the patients, 174 (78%) were followed-up with a mean duration of 66 ±16 months. To calculate the predictive value, the aPL-S was compared with the development of thrombotic events during the follow-up period.


1) The aPL-S was higher in patients with thrombosis/pregnancy morbidity (n=46) than in those without (22.3±26.3 vs. 4.13±10.8, p=0.00001). For the diagnosis of APS, the receiver operating characteristics (ROC) curve of aPL-S showed hyperbolic, and the area under the ROC curve (ROC AUC) are 0.752 and 0.686 for the aPL-S and for the Sydney revised Sapporo criteria, respectively. The prevalence of thrombosis/pregnancy morbidity was correlated with the levels of aPL-S (Figure). 2) Seventeen patients newly developed thromboses; 10 arterial and 10 venous thromboses. Although 18 out of 19 patients with aPL-S >30 received antithrombotic therapy (4 anticoagulant therapies, 14 antiplatelet therapies and 2 both therapies), six of them developed 8 thrombotic events during the follow-up. Patients with aPL-S >30 had a higher risk of thrombosis than those without (Odds-Ratio: 6.04[95%CI: 1.92–18.99, p=0.004]).

Figure. The bar charts indicate the percentages of the prevalence of APS manifestations in each groups of aPL-S. The values inside the bar indicate the number of the patients.


The aPL-S is a useful quantitative index for diagnosing APS, and may be a predictive marker of thrombosis in autoimmune diseases.

To cite this abstract, please use the following information:
Otomo, Kotaro, Atsumi, Tatsuya, Fujieda, Yuichiro, Kato, Masaru, Miyamoto, Eriko, Oku, Kenji, et al; Antiphospholipid Score (aPL-S) in the Antiphospholipid Syndrome: Diagnostic Significance and Predictive Value for the Development of Thrombotic Events in Autoimmune Diseases [abstract]. Arthritis Rheum 2009;60 Suppl 10 :1216
DOI: 10.1002/art.26290

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