Prof. Francesco Violi

Università degli Studi di Roma “La Sapienza”

APS

APS (Antiphospholipid syndrome)

• Definition• Clinical manifestations:

a) venous and arterial thrombosis and foetal loss

b) bleeding disorders

• Mechanism of disease

• Management

The Antiphospholipid Syndrome

It’s a clinical syndrome with widespread arterial and venous thrombosis associated with antibodies directed against phospholipids.

The disorder was classified as “primary” (PAPS), in absence of a concurrent autoimmune condition, such as systemic lupus erythematosus, and secondary (APS) in presence of another autoimmune disease.

Features include stroke and transient ischaemic attack, coronary artery disease, livedo reticularis, pulmonary hypertension, and recurrent aborption. Minor features include labile hypertension, migraine, epilepsy, minor myelopathy,thrombocytaemia, hearth valve disease and ocular ischaemia.

Preliminary Classification Criteria for Antiphospholipid Antibody Syndrome, as Proposed at an International Consensus Workshop, October, 1998

One or more episodes of• Arterial, or• Venous, or• Small vessel thrombosis, in any tissue or organ, confirmed by imaging or Doppler

studies or histopathology. For histopathologic confirmation, thrombosis should be present without significant evidence of inflammation in the vessel wall

• Three or more unexplained consecutive miscarriages with anatomic, genetic or hormonal causes excluded or

• One or more unexplained deaths of a morphologically normal fetus at or after the terth week of gestation with fetal morphology documented by ultrasound or by direct examination of the fetus or

• One of more premature birtrhs of a morphologically normal neonate at or before the 34th week of gestation associated with severe preclampsia or severe placental insufficiency.

Clinical CriteriaVascular Thrombosis:

Pregnancy morbidity:

Lockshin Thromb Haemostas 82:641-648, 1999

• IgG and/or IgM isotype present in• Medium or higher titer,• On two or more occasion, 6 weeks or more apart, and• Measured by standardized ELISA for 2Glycoprotein I-dependent anticardiolipin antibody

Abnormality present in plasma on• Two or more occasions 6 weeks or more apart and• Detected according to the guidelines of the SSC subcommittee on lupus

anticoagulant/phospholipid dependent antibodies in the following steps: Demonstration of a prolonged phospholipid-dependent coagulation screening test (e.g., activated

partial thromboplastin time) kaolin clotting time, dilute Russell viper venom time, dilute prothrombin time, and Textarian time

Failure to correct the prolonged screening test by mixing with normal platelet-poor plasma

Shortening or correction of the prolonged screening test by the addition of excess phospholipid.

Exclusion of other coagulopathies as clinically indicated (e.g., factor VIII inhibitor) and heparin

Preliminary Classification Criteria for Antiphospholipid Antibody Syndrome, as Proposed at an International Consensus Workshop, October, 1998

Laboratory CriteriaAnticardiolipin antibody

Lupus anticoagulant

Lockshin Thromb Haemostas 82:641-648, 1999

Prevalence of antiphospholipid antibody in various pregnancy series

Author Study Group APL ELISA (% +)

LAC (% +)

Harris and Spinnato 1,499 normal pregnancies 1.8

Lockwood et al. 737 normal pregnancies 0.2

Rix et al. 2,856 normal pregnancies 7

Lynch et al. 389 normal pregnancies 4.6 13.7

Infante-Rivard et al. 331 post first pregnancy loss

993 post normal delivery 1.5 1.5

1.8 3.8

Haddoe et al. 309 woman with late

pregnancy loss 618 normal women

0.3 high +

0 high +

Lockshin Thrombosis and Haemostasis 82:641-648, 1999

NORMAL PREGNANCY

Prevalence of antiphospholipid antibody in various pregnancy series

Author Study Group APL ELISA (% +)

LAC (% +)

Parke et al. 81 women with 3+ pregnancy losses

88 normal pregnancies 64 not pregnant

16 7 3

Out et al. 102 women with 3+ early or 1 late

pregnancy losses 102 normal women

21

10

5

0

Petri et al. 44 women with 3+ pregnancy losses 40 women with 0-1 pregnancy loss

11 2.5

9 0

RECURRENT ABORTION

Lockshin Thromb Haemostas 82:641-648, 1999

Bleeding Disorder in APA Patients

• Rare

• Hypoprothrombinemia (20%) and piastrinopenia

• Corticosteroid Treatment

APS (Antiphospholipid syndrome)

• Definition

• Clinical manifestations:

a) venous and arterial thrombosis and foetal loss

b) bleeding disorders

• Mechanism of disease• Management

Mainantigenic Targets Of Antiphospholipid Antibodies (Apl)(React With Antigenic Epitopes In Phospholipid-protein Complexes)

ANIONIC PHOSPHOLIPIDS

(Cardiolipin Phosphatidylserine) Annexin V has potent anticoagulant properties in

vitro, based on its high affinity for anionic phospholipids and its capacity to displace coagulation factors from phospholipids surface. aPL IgG fractions reduce the

quantity of Annexin V in cultured throphoblast and endothelial cells and accelerate the coagulation of plasma

incubated with the cells. The hypothesis is that Annexin V plays a thrombomodulatory apical role on the surface of cells lining the

placental and systemic vasculatures.

PLASMA PHOSPHOLIPID-BINDING PROTEINS

2-Glycoprotein I (2GPI) is the most common and well-characterized antigenic target; aPL preferentially

bind 2GPI that has immobilized on anionic phospholipid membrane.

PROTHROMBIN

(to allow proper immune recognition, must be adsorbed on suitable anionic

surface). The majority of anti-prothrombin antibodies display lupus

anticoagulant activity.

OXIDIZED LOW DENSITY LIPOPROTEIN (LDL)

The major antigenic epitopes are induced in apolipoprotein B during oxidative modification of LDL.

APS: Mechanism of disease

• Experimental studies in animals• In vitro and ex vivo studies:

a) endothelial cell

b) monocytes

c) platelets

Immunogen Area m2 Formation Disappearance Total

-2GP1 2233.7 293.3* 1.9 0.5 5.3 1.7* 7.2 1.8*

IgG-APS 1930.4 212.0* 2.2 1.1 5.4 1.6* 7.6 2.0*

HSA 1266.8 358.6 1.7 0.6 3.1 0.6 4.8 1.1

Time min

Dynamics of thrombus formation in immunized mice

Values are mean SD

* Statistically significant difference from control. Differences between the means of the 2GP1 and IgG-APS groups were not statistically significant

Pierangeli et al. Circulation 94:1746-1751; 1996.

APS: Mechanism of disease

• Experimental studies in animals

• In vitro and ex vivo studies:

a) endothelial cell b) monocytes

c) platelets

Rand et al. N Engl J Med 337:154-60, 1997

O2· OH ·

Native Cardiolipin

Monocyte

Rearrangement

Oxidised Cardiolipin

Antibodies against oxidised cardiolipin

Praticò et al. Blood 93:3401-3407, 1999

APS (Antiphospholipid syndrome)

• Definition

• Clinical manifestations:

a) venous and arterial thrombosis and foetal loss

b) bleeding disorders

• Mechanism of disease

• Management

Randomized Controlled Trials of Treatment for Recurrent Fetal Loss in Women with Antiphospholipid Antibody

Author No.A/B

Regimen A Regimen B Fetalsurvival

A

Fetalsurvival

B

Cowchock et al.12/8 Heparin 12,000 U

bid + ASA 81 mgPrednisone

40mg + ASA 81 mg

80 75*

Kutteh et al.25/25 Heparin 13,300 U

bid + ASA 81 mgASA 81 mg 80 44

Rai et al.45/45 Heparin 5,000 U

bid + ASA 81 mgASA 81 mg 70 40

Kutteh et al.25/25 Heparin 8,100 U

bid + ASA 81 mgHeparin 13,300

U bid +ASA 81 mg

76 80

Lockshin Thrombos Haemostas 82:641-648, 1999

*Marked increase in fetal and maternal morbidity compared to regimen A. ASA=acetyl salicylic acid

Khamashta MA et al. N Engl J Med 332:993-7, 1995

Pat

ien

t s F

r ee

o f T

hr o

mb

o si s

(%

)

Years

Crowther MA et al. N Engl J Med 2003

Andrè et al – Circulation. 2002

Andrè et al – Circulation. 2002

aPL-negative aPL-positive patients (n=16) patients (n=14) p

value

Age (years), Mean ± SD 35±9 39±12

n.s.

Range 18-54 20-56 n.s.

Male sex (n) (%) 2 (13) 1 (7) n.s.

Diabetes Mellitus (n) (%) 5 (31) 5 (35)

n.s.

Hypertension (n) (%) 6 (37) 5 (35)

n.s.

Smoking (n) (%) 6 (37) 4 (29)

n.s.

Platelet count / mm3 191000±52000 212000±49000

n.s.

Disease Activity: SLEDAI score

Low disease activity (n) (%) 11 (69) 10 (71)

n.s.(score 2-9)

High disease activity (n) (%) 5 (31) 4 (29)

n.s.(score _10)

Arth. Rheum. (in press)

Arth. Rheum. (in press)

Arth. Rheum. (in press)