New Direct Assay of Free Protein S Antigen Applied to Diagnosis of Protein S Deficiency

Mf, Aillaud; Pouymayou, Katia; Brunet, D.; Parrot, G; Alessi, Marie‐Christine; Amiral, Jean; Juhan‐Vague, I.

doi:10.1055/s-0038-1650261

Cited by 22 publications

(6 citation statements)

References 15 publications

(1 reference statement)

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“…The ELISA utilizes two monoclonal antibodies, each specific for free protein S epitopes [29]. Briefly, heparinized plasma samples were diluted 1:20 in 1% BSA and duplicate 200 μl samples applied to the precoated 96-well plate.…”

Section: Methodsmentioning

confidence: 99%

“…Free protein S levels were quantified using the free protein S ELISA kit (Diagnostica Stago, Parsippanny, NJ, USA) according to the manufacturer's instructions. The ELISA utilizes two monoclonal antibodies, each specific for free protein S epitopes [ 29 ]. Briefly, heparinized plasma samples were diluted 1:20 in 1% BSA and duplicate 200 μl samples applied to the precoated 96-well plate.…”

Section: Methodsmentioning

confidence: 99%

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TAM receptor ligands in lupus: Protein S but not Gas6 levels reflect disease activity in systemic lupus erythematosus

Suh

Hilliard

et al. 2010

Arthritis Res Ther

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IntroductionThe TAM (tyro 3, axl, mer) kinases are key regulators of innate immunity and are important in the phagocytosis of apoptotic cells. Gas6 and protein S are ligands for these TAM kinases and bind to phosphatidyl serine residues exposed during apoptosis. In animal models, absence of TAM kinases is associated with lupus-like disease. To test whether human systemic lupus erythematosus (SLE) patients might have deficient levels of TAM ligands, we measured Gas 6 and protein S levels in SLE.Methods107 SLE patients were recruited. Of these, 45 SLE patients were matched age, gender and ethnicity with normal controls (NC). Gas6 and free protein S were measured with sandwich enzyme linked immunosorbent assays (ELISAs).ResultsOverall, the plasma concentrations of Gas6 and free protein S were not different between 45 SLE patients and 45 NC. In SLE patients, the levels of free protein S were positively correlated with age (r = 0.2405, P = 0.0126), however those of Gas6 were not. There was no correlation between the concentrations of Gas6 and free protein S in individuals. Levels of free protein S were significantly lower in SLE patients with a history of serositis, neurologic disorder, hematologic disorder and immunologic disorder. Gas6 levels were elevated in patients with a history of neurologic disorder. The SLE patients with anti-Sm or anti-cardiolipin IgG showed lower free protein S levels. Circulating free protein S was positively correlated with complement component 3 (C3) (r = 0.3858, P < 0.0001) and complement component 4 (C4) (r = 0.4275, P < 0.0001). In the patients with active BILAG hematologic involvement, the levels of free protein S were lower and those of Gas6 were higher.ConclusionsIn SLE, free protein S was decreased in patients with certain types of clinical history and disease activity. Levels of free protein S were strongly correlated with C3 and C4 levels. Gas6 levels in SLE patients differed little from levels in NC, but they were elevated in the small numbers of patients with a history of neurological disease. The correlation of decreased protein S levels with lupus disease activity is consistent with a role for the TAM receptors in scavenging apoptotic cells and controlling inflammation. Protein S appears more important functionally in SLE patients than Gas6 in this regard.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

TAM receptor ligands in lupus: Protein S but not Gas6 levels reflect disease activity in systemic lupus erythematosus

Suh

Hilliard

et al. 2010

Arthritis Res Ther

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“…The functional tests are based either on amidolytic or clotting methods. However, the most recent ones are sometimes more difficult to standardize, especially tests for PS activity [101][102][103][104].…”

Section: Selection Of the Biological Testmentioning

confidence: 99%

“…These assays measure either the free or the total PS protein (which include both free PS and PS bound to C4b-binding protein). A new direct assay of free PS has been recently developed using two monoclonal antibodies for distinct epitopes of free PS [104]. It seems that the free PS antigen assay has higher specificity and sensitivity for the diagnosis of PS mutations.…”

Section: Pc and Ps Deficiency Diagnosismentioning

confidence: 99%

Clinical Aspects and Laboratory Problems in Hereditary Thrombophilia

Samama

Gerotziafas²,

Conard³

et al. 1999

Pathophysiol Haemos Thromb

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Hereditary thrombophilia is a multifactorial disease which is mono- or plurigenic and its clinical expression is associated with a heterogeneous expression. Factor V (FV) Leiden and FII gene mutations are more frequent than antithrombin, and protein C and S deficiencies. All thrombophilias are not the same. Heterozygous carriers of FV Leiden or FII gene mutation have a weaker risk of venous thrombosis. The mean age at the first episode is older in the former and higher rate of recurrences is observed in the latter. The cosegregation of mutations significantly increases the risk of thrombosis. Both mutations have a geographic and ethnic distribution in relation with a gene founder effect. Clinical expression consists of deep or superficial venous thrombosis with or without pulmonary embolism, thromboses at unusual sites (e.g. cerebral, portal, mesenteric) or with an increased incidence of fetal loss and abortion. A precipitating cause is present in more than 50% of patients. The risk pf arterial thromboses seems to be restricted to some protein S and FII gene mutations. Laboratory diagnosis strategy should be oriented by careful selection of patients and preanalytical variables should be considered. It is highly probable that other unindentified gene mutations are, at least partly, other causes of the heterogeneous expression of hereditary thrombophilia.

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“…Results are expressed relative to a pooled plasma calibrated against the current International Standard, either as a proportion of the total protein S or, preferably, against the free protein S content. Assays using monoclonal antibodies for distinct epitopes of free protein S allow direct measurement of free protein S in citrated plasma without the need for a precipitation stage (Aillaud et al, 1996).…”

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confidence: 99%