**Clinical criteria**

1. Vascular thrombosis

One or more clinical episodes of arterial,venous or small vessel thrombosis, in any tissue or organ.

	- a. One or more unexplained deaths of a morphologically normal fetus at or beyond the 10th week of gestation, or
	- b. One or more premature births of a morphologically normal neonate before the 34th week of gestation because of eclampsia, severe preeclampsia, or recognized features of placental insufficiency, or
	- c. Three or more unexplained consecutive spontaneous abortions before the 10th week of gestation, with maternal anatomic or hormonal abnormalities and paternal and maternal chromosomal causes excluded.

### **Laboratory criteria**


\*\*\*Definite APLS is present if at least one of the clinical criteria and one of the laboratory criteria are met. Classification of APLS should be avoided if less than 12 weeks or more than 5 years seperate the positive APL test and the clinical manifestation.

Table 1. Updated Sapporo classification criteria for the antiphospholipid syndrome

APLS patients with vascular factors possess other acquired thrombosis risk factors at the

Both persons congenitally lacking ß2GPI39 and ß2GPI knockout mice appear normal(Sheng Y 2001). ß2GPI polymorphisms influence the generation of aPLs in individuals, but they have only a weak relationship to the occurrence of APLS. A cluster of 50 upregulated genes may have an effect on the occurrence of thrombosis in aPL-positive individuals(Potti A

The international preliminary classification criteria for APLS was published in 1999 after a workshop in Sapporo, Japan(Wilson WA 1999)-the so-called Sapporo criteria-. It was updated in 2006 after another workshop in Sydney, Australia(Miyakis S 2006). (table 1).

One or more clinical episodes of arterial,venous or small vessel thrombosis, in any tissue

a. One or more unexplained deaths of a morphologically normal fetus at or beyond

b. One or more premature births of a morphologically normal neonate before the 34th week of gestation because of eclampsia, severe preeclampsia, or recognized

c. Three or more unexplained consecutive spontaneous abortions before the 10th week of gestation, with maternal anatomic or hormonal abnormalities and

1. Lupus anticoagulant present in plasma, on 2 or more occasions at least 12 weeks apart, detected according to the guidelines of the International Society on

2. Anticardiolipin antibody of IgG and/or IgM isotype in serum or plasma, present in medium or high titer(ie, >40 GPL or MPL, or greater than the 99th percentile),on 2 or

\*\*\*Definite APLS is present if at least one of the clinical criteria and one of the laboratory criteria are met. Classification of APLS should be avoided if less than 12 weeks or more than 5 years seperate the

more occasions at least 12 week apart, measured by a standardized ELISA. 3. Anti-β2-glycoprotein I antibody of IgG and/or IgM isotype in serum or plasma(in titer greater than the 99th percentile) present one or more occasions, at least 12 week

Table 1. Updated Sapporo classification criteria for the antiphospholipid syndrome

time of their events(Kaul M 2006, Erkan D 2002).

**4. Diagnostic criteria of the antiphospholipid syndrome** 

2006).

**Clinical criteria** 

or organ.

1. Vascular thrombosis

2. Pregnancy morbidity

**Laboratory criteria** 

Thrombosis and Hemostasis

positive APL test and the clinical manifestation.

the 10th week of gestation, or

features of placental insufficiency, or

apart, measured by a standardized ELISA.

paternal and maternal chromosomal causes excluded.

The first clinical aspect of the APLS is thrombosis, which can affect arterial or venous vessels, as well as small vessels, and must be confirmed by means of imaging studies and/or histopathology. Arterial thrombosis mainly occurs in the central nervous system. But all arteries can be effected and myocardial infarction, peripheral gangrene, aseptic osteonecrosis and adrenal insufficency can develop with respect to effected arterial site. The venous thrombosis commonly localizes to the deep veins of the limbs and can be complicated by pulmonary embolism. As in arterial thrombosis, any segment of the venous vasculature can be effected, which will induce different manifestations.

A definitive diagnosis of APLS is based on fulfilling at least one of the Updated Sapporo Clinical criteria(vascular thrombotic event or pregnancy morbidity) and at least one of the laboratory criteria(Table 1). In general, medium titer aCL is considered 40 U or more and high titer, more than 80 U; titers between 20 and 40 U should be evaluated cautiously. Transient APL positivity is common during infections; thus documentation of the persistence(at least 12 weeks apart) of autoimmune APL is crucial for both diagnostic and therapeutic purposes.

The choice of initial APL tests remains a subject of debate. In general, the LA test is more specific for APL-related clinical events. The specificity of aCL for APL-related clinical events increases with higher titers. The IgG isotype is more strongly associated with APL-related clinical events than the IgM isotype. In a patient with suspected APS, testing for LA and IgG/IgM aCL should be ordered initially. If these tests are negative or low-titer and there is still a high level of suspicion for APS, then testing for antiβ2GPI antibodies and IgA aCL/antiβ2GPI can be pursued(George D 2009). Antiphospholipid antibody tests developed based on other phospholipids such as phosphatidylserine, phosphatidylinositol, or phosphatidylethanolamine or phospholipid-binding plasma proteins(such as prothrombin) are not yet well standardized and accepted.
