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 34 th week of gestation associated with severe preclampsia or severe placental insufficiency. Clinical Criteria Vascular Thrombosis: Pregnancy morbidity: Lockshin Thromb Haemostas 82: , 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 Criteria Anticardiolipin antibody Lupus anticoagulant Lockshin Thromb Haemostas 82: , 1999

Prevalence of antiphospholipid antibody in various pregnancy series Lockshin Thrombosis and Haemostasis 82: , 1999 NORMAL PREGNANCY

Prevalence of antiphospholipid antibody in various pregnancy series RECURRENT ABORTION Lockshin Thromb Haemostas 82: , 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

Time min Dynamics of thrombus formation in immunized mice Values are mean  SD * Statistically significant difference from control. Differences between the means of the  2 GP1 and IgG-APS groups were not statistically significant Pierangeli et al. Circulation 94: ; 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

O 2 · OH · Native Cardiolipin Monocyte Rearrangement Oxidised Cardiolipin Antibodies against oxidised cardiolipin

Praticò et al. Blood 93: , 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 Lockshin Thrombos Haemostas 82: , 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 Patients Free of Thrombosis (%) Years

Crowther MA et al. N Engl J Med 2003

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 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 / mm ± ±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)