Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Prevalence of Antibodies to Prothrombin (PT) and Prothrombin/Phosphatidylserine (PS) in a Cohort of Lupus Anticoagulant (LAC) Positive Samples.

Aguilar-Valenzuela2,  R., Dlott1,  J., Khan2,  U., Belter1,  M., Doan2,  E., Gould1,  N., Schleh2,  A.

Quest Diagnostics, Chantilly, VA
Univ of TX Med Branch, Galveston, TX

Background:

ELISA tests have been developed to detect anti-PT and anti-PT/PS antibodies in serum but the clinical diagnostic value and their relationship with the LAC remains elusive.

Objective:

to evaluate anti-PT/PS and anti-PT antibodies in a cohort of 150 confirmed LAC and the corresponding controls.

Methods:

150 LAC positive and 150 LAC negative plasma samples were tested by ELISA for anti-PS/PT (IgG and IgM) and LAC PS/PT screening assay (kindly provided by INOVA Diagnostics) and anti-PT (IgG and IgM) in-house assay. LAC positivity was confirmed by either dRVVT Confirm (American Diagnostica) or by the STACLOT LA (Diagnostica Stago) tests (3% of samples were positive for dRVVT only and 94% were positive for STACLOT only, 3% were positive for both).

Results:

 aPS/PT IgGaPS/PT IgMaPS/PT ScreenaPT IgGaPT IgM
# of positive samples (%)43/150 (29%)33/150 (22%)32/150 (21%)44/150 (29.3%)39/150 (26%)

All negative LAC samples were negative in the anti-PS/PT and anti-PT tests. 125/150 (83%) of all LAC positive samples were positive in at least one of the PS/PT or PT ELISA. There was no correlation between any of the tests and LAC Staclot delta values or dRVVT ratios and the PT/PS or PT tests. Strong correlation was observed between anti-PS/PT IgG or IgM and LAC Anti-PS/PT screen test.

Conclusions:

PS/PT and PT antibodies altogether recognize the majority of LAC positive samples and may represent an additional specific serological laboratory marker to confirm diagnosis of Antiphospholipid Syndrome.

To cite this abstract, please use the following information:
Aguilar-Valenzuela, R., Dlott, J., Khan, U., Belter, M., Doan, E., Gould, N., et al; Prevalence of Antibodies to Prothrombin (PT) and Prothrombin/Phosphatidylserine (PS) in a Cohort of Lupus Anticoagulant (LAC) Positive Samples. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :12
DOI: 10.1002/art.27782

Abstract Supplement

Meeting Menu

2010 ACR/ARHP