ANTIPHOSPHOLIPID_ANTIBODY

1. ANTIPHOSPHOLIPID ANTIBODY

2. • Antiphospholipid antibody syndrome is an autoimmune disorder
which is characterized by arterial/ venous thrombosis and/or
pregnancy morbidity. It is known as HUGHES syndrome.
• Types of APS :
• Primary
• Secondary: Associated with other autoimmune disorders.
• Note: Catastrophic APS

3. • Autoantibodies associated with Antiphospholipid antibody
syndrome are:
1)Antibodies against Cardiolipin
2) Antibodies against Beta 2 Glycoprotein
3) Lupus Anticoagulant

4. • Pathophysiology:
Basic mechanism is conversion of physiological state of the body into
a “PROTHROMBOTIC STATE”
1)Disruption of endothelial surface and annexin A5 anticoagulant
shield.

5. 2) Impeding of fibrinolysis and endogenous anticoagulation
• Interference with plasminogen and tissue plasminogen activator
• Interference with components of protein C activation pathway
3)Activation of platelets
• Interference with Beta 2 glycoprotein.

6. Clinical manifestations:
 Venous Thrombosis
Arterial thrombosis
Obstetric manifestation

7. • Introduction

9. • Diagnostic criteria: The presence of one clinical and one laboratory
criterion is compatible with the diagnosis of APLA syndrome.
• Clinical Criteria:
• 1)Vascular thrombosis(One or more episodes of
arterial/venous/small vessel thrombosis
• 2) Pregnancy morbidity(either of 3 sub criteria)
• Laboratory criteria:
• LA, anti CL and /or anti Beta 2 GP1
• At intermediate or high titers on two occasions 12 weeks apart.

10. Samples
• Citrated sample: 2( for LA testing)
• EDTA sample: 1( for platelet count)
• Plain blood sample: 1 (for ELISA)

11. Lupus anticoagulant
• Lupus anticoagulant inhibit in vitro phospholipid dependent
activation of Factor IX, Factor X and Prothrombin.
• These antibodies bind to prothrombin and increase their conversion
into Thrombin

12. First step:
• We conduct coagulation screening to detect the prolongation of
the test( usually aPTT)
• If it is prolonged then we do mixing studies;
If it is corrected : delay is due to factor deficiency
If it is not corrected: there is a presence of an inhibitor
Second step: To confirm phospholipid dependency of inhibitor
This can be done by adding Phospholipids/platelets and checking
whether there is any correction of the value.
Perform second test: Either Kaolin clotting test/ DRVVT.

13. • Tests for Lupus anticoagulant:
• aPTT
• DRVVT(Direct Russell Viper Venom test)

14. APTT
• Activated Partial Thromboplastin Time:
APTT is a sensitive to deficiencies of the intrinsic pathway(VIII, IX, XI,
XII), common pathway(V, X, II, I) and also to the presence of inhibitors
or heparin.
APTT measures the clotting time of plasma after the activation of
contact factors but without added tissue thromboplastin and so
indicates the overall efficiency of intrinsic pathway.
Normal range for APTT: 26-35 seconds.

15. Mixing studies
• Principle:
Unexplained prolongation of PT or APTT can be investigated with
simple correction tests by mixing the patients plasma with control
plasma and other reagents.
Correction indicates a possible factor deficiency , whereas failure to
correct suggests the presence of inhibitor.

17. DRVVT

18. • The inhibitory effect of lupus anticoagulants on phospholipids in the
dRVVT can be overcome by adding an excess of phospholipid to the
assay.
• The clotting times of both the initial dRVVT assay and confirmatory
test are normalized and then used to determine a ratio of time
without phospholipid excess to time with phospholipid excess.
• In general, a ratio of greater than 1.3 is considered a positive result
and implies that the patient may have antiphospholipid antibodies.

19. Kaolin clotting time
• The kaolin clotting time (KCT) is a sensitive test used in the laboratory
detection of lupus anticoagulants.
• It is similar to aPTT but there is no phospholipid added in the test.
• Kaolin acts as an activator in the test.
• The test contains no exogenous phospholipid, a confirmatory test
using excess phospholipid is required to confirm the presence of
lupus anticoagulant in the sample
• The KCT test/control ratio of greater than or equal to 1.2 indicates
that a defect is present. If the test/control ratio is between 1.1 and
1.2, the test is equivocal.

20. Anticardiolipin antibody:
 As the name suggests, it is the antibody against cardiolipin.
Cardiolipin is an important component of the mitochondrial
membrane.
 The test used to detect is ELISA( Enzyme linked immunosorbent
assay)
 It is consiered when the value is >40units( high titre) according to
Sydney criteria.

22. • Anti Beta 2 Glycoprotein 1 antibodies:
Antibodies recognize β2GPI bound in the absence of CL to an oxidized
polystyrene surface, where oxygen atoms in the moieties C–O or C=O
were introduced by γ-irradiation.

23. • This test is considered to be more specific and less sensitive when
compared to the Anticardiolipin antibody.
• The test is considered positive if the value>99th percentile.

24. • Various other tests are also available for the detection of LA
• Such as :
• Tissue thromboplastin test
• Hexagonal phase array test
• Textarin/ecarin test
• aPL sensitive and insensitive reagents and platelet neutralization test.

25. • Antiphospholipid antibody syndrome is a syndrome that needs to
diagnosed as early as possible and managed, as it can lead to life
threatening complications.
• Therapy is usually based on anticoagulation.
• After the first thrombotic event the patient is placed on Heparin
therapy for life, with or without combination of Aspirin.

26. Thank you

27. References
• Kaushansky, K. and Levi, M., n.d. Williams Hematology. 9th ed. pp.2233-
2245.
• Bustamante JG, Goyal A, Bansal P, et al. Antiphospholipid Syndrome
(Antiphospholipid Antibody Syndrome, APS, APLS) Feb 2020
• Chaturvedi, Shruti, and Keith R McCrae. “Diagnosis and management of the
antiphospholipid syndrome.” Blood reviews vol. 31,6 (2017): 406-417.
doi:10.1016/j.blre.2017.07.006
• Jameson J, Kasper D, Fauci A, Hauser S, Longo D, Loscalzo J et al. Harrison's
principles of internal medicine. 20th ed.pp.2526-2527
• Kumar V, Abbas A, Aster J, Cotran R, Robbins S. Robbins and Cotran
Pathologic Basis of Disease. 9th ed.

28. MCQ’s
• The APS syndrome is also called as :
a) Hughes syndrome
b) Sheehan’s syndrome
c) Wermer syndrome
d) Sipple syndrome

29. • Which of the following features is included in the clinical criteria of
the APS syndrome?
a) Cerebral arterial thrombosis
b) Deep vein thrombosis
c) Abortion <10 weeks
d) AIHA

30. • Which of the following is most specific antibodies associated with APS
syndrome?
a) Anti cardiolipin antibody
b) Anti beta 2 glycoprotein
c) Anti phosphotidyl serine
d) Antiphosphotidylcholine