Antiphospholipid syndrome was

described in full in the 1980s, after

various previous reports of specific

antibodies in people with systemic lupus

erythematosus and thrombosis.

The syndrome is sometimes referred to as "Hughes syndrome",

after the rheumatologist Dr. Graham R.V. Hughes who worked

at the Louise Coote Lupus Unit at St Thomas' Hospital in London

and played a central role in the description of the condition.

In young,app healthy people---for LA, antiCL is 1-5%

Prevalence ↑ with age ,in elderly with chronic disease.

Mean age of onset-31 yrs,Low age 8 months

Risk of thrombosis is 0.5-30%

Women :men is 5:1

Females---arthritis,livedo,migraine

Males—MI,epilepsy,lower extremity arterial thrombosis

More common in african americans.

Without rheumatic disease at younger age and

with rh –older

Apl ab—30-40% in SLE---10% have APLS

Idiopathically—ACL-24%,LA-4%

Antiphospholipid syndrome or antiphospholipid antibody

syndrome (APS or APLS or), often also Hughes syndrome,

is an autoimmune, hypercoagulable state caused by antibodies

against cell-membrane phospholipids that provokes blood clots

(thrombosis) in both arteries and veins as well as

pregnancy-related complications such as

miscarriage, stillbirth, preterm delivery, or severe preeclampsia.

The syndrome occurs due to the autoimmune production of

antibodies against phospholipid (aPL), a cell membrane substance.

In particular, the disease is characterised by antibodies against

cardiolipin (anti-cardiolipin antibodies) and β2 glycoprotein I.

Risk factors for developing antiphospholipid syndrome include:•Primary APS

genetic marker HLA-DR7•Secondary APS

SLE or other autoimmune disordersGenetic markers: HLA-B8, HLA-DR2, HLA-DR3Race: Blacks, Hispanics, Asians, and Native Americans

Disruption of vascular endothelial lining allows exposure of blood to

subendothelial connective tissue:

Primary hemostasis (seconds)

- Platelet plug formation at site of injury

- Stops bleeding from capillaries, small

arterioles and venules

Secondary hemostasis (minutes)

- Fibrin formation by reactions of

the plasma coagulation system

Defects in primary hemostasis

Thrombocytopenia

Defects in secondary

hemostasis

Clotting factor

deficiencies

Prethrombotic(hypercoagulable) states

Inherited

Acquired

• Anti-thrombin deficiency

• Deficiencies of protein C and S

• Resistance to activated protein C •( factor V Leiden mutation)

• Prothombin gene mutation• ( G20210A)

Homocystinemia

Conditions associated with a hypercoagulable state:

- pregnancy and postpartum - major surgery- obesity and immobility - malignancy- congestive heart failure- nephrotic syndrome

Estrogen treatment

Antiphospholipid syndrome

Antiphospholipid syndrome is an autoimmune disease, in which

"antiphospholipid antibodies" :

1.anticardiolipin antibodies (ACA)

2. lupus anticoagulant(LA)

react against proteins that bind to anionic phospholipids on

plasma membranes.

ACA– are directed against cardiolipin

They may be b2 gp1 dependent or independent

(Independent—syphilis)

B2 gp1-----apolipoprotein H

Bind with cardiolipin ab - thrombosis

• b2GPI a plasma protein with affinity for negatively charged phospholipids

• anti- b2GPI: are probably the major cause of APS

Anticardiolipn abs recognize in most assays: b2 GPI

Lupus Anticoagulant activity is caused by autoantibodies to:

- b2 GPI

- prothrombin

Anionic phospholipids

The exact cause is not known, but

activation of the system of coagulation is

evident.

Homeostatic regulation of blood coagulation is altered.

1.defect in cellular apoptosis- exposure of membrane phospholipids to the binding of various plasma proteins---b2gp1---

complex—epitope---target for autoantibodies.

2.oxidized b2GP1---activates dendritic cells –autoantibodies are

produced.

3.production of antibodies against prothrombin, proteinC, S

annexins.

4.activation of platelets to enhance endothelial adherence.

5.activation of vascular endothelium—platelet and monocyte

binding.

6.ab against oxidized LDL — atherosclerosis.

Complement activation has been increasingly recognised as a

possible significant role in the pathogenesis of APS.

The family of APL ab are heterogenous and the targets vary.

APS can be caused by –LA,ACA,B2GP1 or other antibodies.

There are distinct clinical ,laboratory and biochemical differences

between the disorders mediated by the different antibodies.

ACL---risk of stroke—arterial thrombosis

LA-venous

TNF alpha –pregnancy loss

Coagulation pathway

Annexin ˅

The syndrome can be divided into primary (no underlying disease state)

and secondary (in association with an underlying disease state) forms.Anti-ApoH and a subset of anti-cardiolipin antibodies bind to ApoH, which in turn inhibits Protein C, a glycoprotein with regulatory function upon the common pathway of coagulation (by degradating activated factor V).

Clinically important antiphospholipid antibodies (those that

arise as a result of the autoimmune process) are associated

with thrombosis and vascular disease.

LAC antibodies bind to prothrombin , thus increasing its cleavage to thrombin, its active form .In APS there are also antibodies binding to: Protein S, which is

a co-factor of protein C.

Thus, anti-protein S antibodies decrease protein C efficiency;

Annexin A5, which forms a shield around negatively-charged

phospholipid molecules, thus reducing their availability for

coagulation.

Thus, anti-annexin A5 antibodies increase phospholipid-

dependent coagulation steps.

The Lupus anticoagulant antibodies are those that show the closest

association with thrombosis, those that target β2glycoprotein 1 have a

greater association with thrombosis than those that target prothrombin.

Anticardiolipin antibodies are

associated with thrombosis

at moderate to high titres

(>40 GPLU or MPLU).

Patients with both Lupus anticoagulant antibodies and moderate/high titre

anticardiolipin antibodies show a greater risk of thrombosis than with one

alone .

APL antibodies and NF-B

Intracellular events in EC induced by aPL antibodies:

aPL induce activation of NF-B and correlates with EC activation in vitro and in vivo and with thrombosis in vivo. Espinola RG et al: J Thromb Haemost, 2003; 1: 843-

848.

Dunoyer-Geindre S. et al. Thromb Haemost. 2002; 88: 851-857.

Bohgaki M, et al. Int Immunol. 2004; 16: 1632-1641.

Pathogenesis

In Pregnancy

This Syndrome is characterized by:

Arterial or Venous Thrombosis

Thrombocytopenia

Recurrent Fetal Loss

Serum Anti-phospholipid antibodies (aPL)

1. Primary antiphospholipid syndrome

APS occurs in the absence of any other related disease.

2. Secondary antiphospholipid syndrome

APS occuring in the context of other autoimmune

diseases, such as systemic lupus erythematosus (SLE).

3. Catastrophic antiphospholipid syndrome

In rare cases, APS leads to rapid organ failure due to

generalised thrombosis; this is termed (CAPS) and is

associated with a high risk of death.

Venous Thromboembolism: Arterial Occlusion: Stroke and TIAs are

the most common

Pulmonary Embolism

Deep Vein Thrombosis

Recurrent fetal loss

In women with recurrent miscarriage due to APS fetal loss rate: as high as 90%

antiphospholipid abs are associated with:

- placental insufficiency

- early preeclamapsia

- IUGR- intrauterine growth restriction

Pregnancy Morbidity

aPL associated

manifestations (individual

diagnosis)

Thrombocytopenia

(occurs in up to 50%)

Cardiac valve disease

Livedo reticularis

Nephropathy ( late

manifestation)

Sydney revision of Sapporo criteria 2006

Livedo reticularis with necrotic finger tips in

Antiphospholipid syndrome

Transverse Myelitis

Migraine

Chorea

Leg ulcers

UBOs (white matter lesions) on brain MRI

not included in criteria

Infection:

- Syphilis, TB, Q-fever, Spotted Fever, Klebsiella, HCV, Leprosy,HIV.

- The abs are usually transient, not b2 GPI dependent

Malignancy:

Lymphoma, paraproteinemia

Drug induced:

phenothiazines, procainamide, quinidine, phenytoin, hydralazine

Common auto immune diseases ass with APL ab are

1.SLE-25-50%

2.sjogren’s –42%

3.RA-33%

4.AITP-30%

5.AIHA-unknown

6.MCD-22%

7.behcet-20%

Spontaneous venous thromboembolism

Recurrent VT, even in presence of other risk factors

Stroke or peripheral arterial occlusive event at < 50 yrs

In all SLE patients

In women with > 3 consecutive pregnancy losses

loss of morphologically normal fetus at II-III trimester

early severe preeclampsia

severe placental insufficiency low prevalence in general obstetric

population (< 2% ): screening not warranted

APA---IgG,IgA,IgM

SEVERAL antibodies are recognised

Recently—antibodies against annexin V,protein C

IgM acl---HEMOLYTIC ANEMIA.

IgG ACL –thrombosis

False positive test result for syphilis

ACL—membrane phospholipids

LA-plasma coagulation molecules

Elongates APTT,Kaolin clotting time,dilute russells viper venom time.

Advantages

Overwhelming majority of APS patients are anti cardiolipin positive

Test can be performed reproducibly.

Clinicians and laboratories generally familiar with units of measurement.

Disadvantages

Relatively nonspecific (particularly low positive, IgM positive).

Intra-laboratory and Inter-laboratory variability.

Problems with false positive results: aCL positive in a wide variety of infectious diseases and in non-APS related autoimmune diseases.

Solid phase assays usually anti-Cardiolipin abs

IgG aCL levels below 21.4 = probability of thrombosis 0.07

IgG aCL levels >21.4 and < 65.0 GPL = probability of

thrombosis 0.20

IgG aCL levels >65.1 GPL units = probability of thrombosis

0.75

Predictive value of IgG aCL for thrombosis in patients with SLE

Perform coagulation screen to detect prolongationin phospholipid dependent coagulation assay (usually use: APTT)

If APTT is prolonged: Mix with normal plasma

- If due to factor deficiency: corrected

- If due to inhibitor (antibody) not corrected

Confirm inhibitor is phospholipid dependent : corrected by mixing with platelets or phospholipids

Perform second test: KCT or DRVVT

APTT:- variability in reagents result in

inconsistent sensitivity.

- acute phase reaction and pregnancy may shorten APTT and mask

a weak LAC

A normal APTT does not exclude LAC

KCT- Kaolin clotting time

more sensitive to presence of anti-II

DRVVT- Dilute Russell’s viper venom time

more sensitive to presence of b2 GPI

TTI - Tissue thromboplastin inhibition test

No LAC shows 100% specificity and

sensitivity because aPLs are heterogeneous.

More than 1 test system is needed

Diluted Russells viper venom test

Kaolin Clotting Test

Based on observation that antiphospholipid antibodies cross-react with

negatively charged phospholipids but syphilis and other infectious diseases

sera largely limited to cardiolipin binding (no cross-reactivity)

Construction of a kit with negatively charged phospholipids might eliminate non-specific binding.

Antigen composed of mixture of phospholipids instead of cardiolipin

Sensitivity of APS (greater than 90%)

More specific than anticardiolipin test and at least as specific (or more) compared to anti-ß2GPI

Incorporation of an in-house positive control

Can be utilized for first line testing, and certainly important in confirmation of APS

Principle

Patient Laboratory Data

PT 20.6 sec aPTT 100.3 sec

TCT 8.8 sec DRVVT ‘No clot’

Factor VIII ‘Inhibitory’ Factor IX <1.6%

Factor XI <1.6% Bethesda titer 2.8 U

Platelets 120,000/ml Factor X 68%

Additional Laboratory Data

Factor V (aPTT) “Inhibitory”

Factor V (PT) 115%

Factor II 38%

Fibrinogen 795.6 mg/dl

D-dimer >4.37 mcg FEU/ml

Repeat DRVVT (ratio) 3.23

DRVVT Confirm (ratio) 2.17

Alternative strategies to

identify a lupus anticoagulant

Platelet neutralization procedure (PNP; uses platelet

membranes).

Hexagonal phase phospholipid assay (StaClot LA; uses PE

in a hexagonal phase conformation).

Textarin/Ecarin clot time.

Factor V analysis by PT and aPTT-based assays.

What if LA,ACL are negative

If patient experiencing thrombosis or recurrent miscarriages

Order

Antibodies to b2 gp1

Ab to phosphatidylserine,ethonalamine,glycerol,inositol

Annexin V

Phosphatidyl choline.

Imaging studies

For confirmation

USG

COLOR DOPPLER

CT SCAN

MRI

2D ECHO

Histology----

non inflammatory bland thrombosis with no signs of

perivascular inflammation or leukocytoclastic vasculitis.

Lupus anticoagulant detected and confirmed.

Multiple factor deficiencies in aPTT pathway reflect high-titer lupus

anticoagulant.

Prolonged PT reflects mild factor II deficiency and lupus anticoagulant

effect.

Elevated D-dimer reflects recent thrombosis.

Elevated inhibitor titer due to lupus anticoagulant.

DIFFERENTIAL DIAGNOSIS

Think of any other thrombophilic states before making a diagnosis of APLS.

Malignancy

OCP

Homocysteinemia

Antithrombin 111 def

Protein C,S def

Factor V leiden mutation

Incidental finding of antiphospholipid antibodies

Anti-thrombotic therapy not usually

indicated

Low threshold for thromboprophylaxis at

times of high risk

Some suggest low dose Aspirin prophylaxis

Reduce other risk factors for thrombosis

INR

The ISI—1.0-2.0

INR—5 high chance of bleeding

0.5--- clot formation

Normal range is 0.9-1.3

Warfarin ---2.0-3.0

Prosthetic valves—3.0-4.0

• Eliminate other risk factors, such as oral contraceptives,

smoking, hypertension, or hyperlipidemia.

• Low-dose aspirin is used widely in this setting; however, the

effectiveness of low-dose aspirin as primary prevention for

APS remains unproven.

• Clopidogrel has anecdotally been reported to be helpful in

persons with APS and may be useful in patients allergic to

aspirin.

• In patients with SLE, consider hydroxychloroquine, which

may have intrinsic antithrombotic properties.

•Consider the use of statins, especially in patients with

hyperlipidemia.

Prophylactic therapy

• Perform full anticoagulation with intravenous or

subcutaneous heparin followed by warfarin therapy.

• Based on the most recent evidence, a reasonable

target for the international normalized ratio (INR) is 2.0-3.0

for venous thrombosis and 3.0 for arterial thrombosis.

• Patients with recurrent thrombotic events, while well

maintained on the above regimens, may require an INR

of 3.0-4.0.

• For severe or refractory cases, a combination of

warfarin and aspirin may be used.

•Treatment for significant thrombotic events in patients

with APS is generally lifelong.

Thrombosis

Mild to moderate- Platelets > 50,000:

No treatment

Severe- <50,000:

- corticosteroids

- corticosteroid resistant cases:

HCQ , IVIG, Immunosuppressive drugs,

Splenectomy

Management of aPL positive patients with adverse

pregnancy history

Poor obstetric history - the most important predictor

The risk of fetal loss is related to aCL ab titer

Presence of aPL are a marker for a high risk pregnancy

Once APS is diagnosed, serial aPL testing is not useful

Current Recommendations

Pregnancy Fetal protection

Asymptomatic aPL no treatment

Single loss <10wks no treatment

Recurrent loss* <10wks prophylactic heparin +ASA

up to 6-12 wks postpartum, ASA after(?)

Recurrent loss < 10 wks therapeutic heparin + ASA,

+ thrombosis warfarin postpartum

Prior thrombosis therapeutic heparin + ASA

warfarin postpartum

* Late fetal loss

IUGR

severe pre-

eclampsia

Other therapies for aPL associated

pregnancy loss

Corticosteroids :- associated with significant maternal and fetal morbidity

- ineffective

Immunosuppression:

azathioprine, plasmapheresis:

numbers treated too small for conclusion

IVIG:may be salvage therapy in women who fail on

Heparin + Aspirin

Fetal Monitoring

US monitoring of fetal growth and amniotic fluid

every 4 weeks

US monitoring of uteroplacental blood flow: uterine artery waveforms assessed at 20-24 wks

If early diastolic notch seen: do 2 weekly growth scans due to high risk of IUGR

FOLLOW UP

Frequent check ups

Adequate patient education

Avoidance of smoking

Strict control with anticoagulants.

In case of bleeding –hospital.

Normal healthy life

With appropriate medication and lifestyle modifications, most

individuals with primary antiphospholipid syndrome (APS) lead

normal healthy lives.

However, subsets of patients continue to have thrombotic events

despite aggressive therapies. In these patients and in patients with

CAPS, the disease course can be devastating, often leading to

significant morbidity or early death.

A retrospective study suggested that hypertension or medium-to-high titers of IgG anticardiolipin antibody are risk factors for a first

thrombotic event in asymptomatic patients with antiphospholipid

(aPL) antibodies.[18] Primary prophylaxis against thrombosis appears to offer significant protection in such cases.

Prognosis

Patients with secondary APS carry a prognosis similar to that of

patients with primary APS; in the former, however, morbidity and

mortality may also be influenced by these patients' underlying autoimmune or rheumatic condition. In patients with SLE and APS,

aPL antibodies have been associated with neuropsychiatric disease

and have been recognized as a major predictor of irreversible organ

damage.

Women with aPL antibodies who experience recurrent miscarriages may have favorable prognoses in subsequent pregnancies if treated

with aspirin and heparin.

Future Directions

Can? we predict which patients with antiphospholipid antibodies will

develop thromboembolic complications?

Is there an inherited predisposition to developing antiphospholipid

antibody syndrome

Genomic strategy

Whole blood RNA prepared using PAXgene system from patients

with APS and selected control populations.

RNA extracted and validated.

Oligonucleotide arrays printed at the Duke Microarray Facility,

using the Operon Human Genome Oligo Set Version 3.0 (Operon,

Huntsville, AL).

-- Potti, et al., Blood, 2006; 107: In press.

Discovery ModePreliminary data with patients and ‘controls’

Controls with VTE APS NormalaPLA

Up regulated Down regulated

Family history

Asymptomatic

daughter tests

positive for a

lupus

anticoagulant.

Mother developed

arterial thrombosis

and

thrombocytopenia

prior to her death.

Familial Antiphospholipid Syndrome

Family members of patients with APS have an increased incidence of

autoimmune disorders.

“Genetics of APS” is a clinical trial being developed by the Rare

Thrombotic Diseases Clinical Research Consortium.