PMID- 10404770
OWN - NLM
STAT- MEDLINE
DCOM- 19990824
LR  - 20061115
IS  - 0340-6245 (Print)
IS  - 0340-6245 (Linking)
VI  - 81
IP  - 6
DP  - 1999 Jun
TI  - Lupus anticoagulant testing in Europe: an analysis of results from the first 
      European Concerted Action on Thrombophilia (ECAT) survey using plasmas spiked 
      with monoclonal antibodies against human beta2-glycoprotein I.
PG  - 929-34
AB  - Lupus anticoagulants (LA) are immunoglobulins directed to either prothrombin or 
      Beta-2-glycoprotein 1(beta1GPI) bound to phospholipids. Most patients with LA 
      have both beta2GPI- and prothrombin-dependent antibodies. Several recent reports 
      have shown that LA is more strongly associated with thrombosis than 
      anticardiolipin antibodies (aCL). Therefore, an accurate detection of LA is of 
      utmost importance in patients suspected of an antiphospholipid syndrome. We 
      recently raised a series of murine monoclonal antibodies against human 
      Beta-2-glycoprotein I (beta2GPI) with LA activity similar to affinity purified 
      human beta2GPI-dependent LAs. A normal plasma pool, and the same pool spiked with 
      LA positive anti-beta2GPI antibodies at two potency levels, were used as 
      materials in an external quality assessment scheme organised by the European 
      Concerted Action on Thrombosis (ECAT). Fifty nine laboratories participating in 
      this trial were asked to test for the presence of a LA in the 3 samples 
      submitted. The majority (82%) of the participants found the high potency LA 
      sample to be positive. Only 37% of the laboratories considered the weak potency 
      LA sample to be positive. The submission of a normal sample, a weakly positive 
      sample and a clearly positive sample enabled us to compare the relative LA 
      responsiveness of the different screening assays used. Clotting time ratios 
      varied from 0.81 to 3.28 for sample B and from 0.66 to 5.32 for sample D. In 
      general, the highest clotting time ratios were found with the dilute prothrombin 
      time (dPT), the dilute Russell Viper Venom time (dRVVT) and the Kaolin Clotting 
      time. The most frequently used screening tests were the aPTT and the dRVVT. With 
      the various assay systems, LA responsiveness varied largely according to the 
      reagents used. For the beta2GPI-dependent LA used in this study, PTT LA clearly 
      showed the highest responsiveness among the aPTT reagents and Innovin among the 
      dPT reagents. The present study also shows that many laboratories still rely on 
      poorly responsive screening assays for their LA tests. Other laboratories rely on 
      sensitive and more specific integrated test systems based on a sensitive 
      screening assay with a low phospholipid content and a confirmatory test employing 
      high phospholipid concentrations. The most used integrated system was dRVVT 
      based. However, also here the LA responsiveness was largely reagent dependent. In 
      conclusion, many laboratories still rely on poorly responsive screening assays by 
      which weakly positive LA samples are misdiagnosed. LA positive anti-beta2GPI 
      moabs have a potential for the unlimited production of LA control specimens, that 
      may help hemostasis laboratories choose more LA responsive assay systems and to 
      assess intralaboratory precision of their LA testing.
FAU - Arnout, J
AU  - Arnout J
AD  - Center for Molecular and Vascular Biology, University of Leuven, Belgium. 
      jef.arnout@med.kuleuven.ac.be
FAU - Meijer, P
AU  - Meijer P
FAU - Vermylen, J
AU  - Vermylen J
LA  - eng
PT  - Journal Article
PT  - Multicenter Study
PL  - Germany
TA  - Thromb Haemost
JT  - Thrombosis and haemostasis
JID - 7608063
RN  - 0 (Antibodies, Monoclonal)
RN  - 0 (Glycoproteins)
RN  - 0 (Lupus Coagulation Inhibitor)
RN  - 0 (beta 2-Glycoprotein I)
SB  - IM
MH  - Antibodies, Monoclonal/*immunology
MH  - Europe
MH  - Glycoproteins/*blood/*immunology
MH  - Humans
MH  - Immunoassay
MH  - Lupus Coagulation Inhibitor/*blood
MH  - Thrombophilia/*blood/immunology
MH  - beta 2-Glycoprotein I
EDAT- 1999/07/15 00:00
MHDA- 1999/07/15 00:01
CRDT- 1999/07/15 00:00
PHST- 1999/07/15 00:00 [pubmed]
PHST- 1999/07/15 00:01 [medline]
PHST- 1999/07/15 00:00 [entrez]
AID - 99060929 [pii]
PST - ppublish
SO  - Thromb Haemost. 1999 Jun;81(6):929-34.