Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or... – Involving antigen-antibody binding – specific binding protein...
Reexamination Certificate
2001-11-07
2003-09-02
Chan, Christina (Department: 1644)
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
Involving antigen-antibody binding, specific binding protein...
C530S358000, C530S380000, C530S388250
Reexamination Certificate
active
06613532
ABSTRACT:
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The invention relates to a method to determine predisposition to coagulation disorders, such as thrombosis, to a method for the diagnosis of lupus, and method of treatment of coagulation disorders.
(b) Description of Prior Art
The major causes of acquired coagulation disorders are (1) vitamin K deficiency, (2) liver disease, (3) disseminated intravascular coagulation (DIC), and (4) development of circulating anticoagulants, which are usually antibodies (Abs) to hemostatic factors.
DIC usually results from entrance into or generation within the blood of material with tissue factor activity (TFA), which initiates coagulation. DIC usually arises in 1 of 3 clinical circumstances: (1) In complications of obstetrics, uterine material with TFA gains access to the maternal circulation (eg, in abruptio placentae, a saline-induced therapeutic abortion, retained dead fetus syndrome, and the initial phase of amniotic fluid embolism). (2) Infection is present, particularly with gram-negative organisms. Adding gram-negative endotoxin to blood in vitro causes generation of TFA on the plasma membrane of monocytes. This presumably represents a primary mechanism for endotoxin-induced DIC, since depletion of blood monocytes in rabbits by giving the alkylating agent nitrogen mustard protects the animals from developing DIC after injection of endotoxin. (3) Malignancy is present, particularly mucin-secreting adenocarcinomas of the pancreas and prostate and a form of acute leukemia, acute promyelocytic leukemia, in which hypergranular leukemic cells are thought to release material from their granules with TFA.
The guiding principle of therapy is to identify and correct the underlying cause without delay (eg, broad-spectrum antibiotic treatment of suspected gram-negative sepsis, evacuation of the uterus in abruptio placentae). Once this is accomplished, DIC should subside quickly. If the patient is bleeding seriously, replacement therapy is indicated: platelet concentrates to correct thrombocytopenia (and also as a source of factor V in platelets); cryo-precipitate to replace fibrinogen and factor VIII; fresh frozen plasma to increase levels of factor V, other clotting factors, and as a source of antithrombin III, which may also be depleted secondary to DIC.
Endogenous substances that inhibit blood coagulation are usually antibodies (Abs) that neutralize a clotting factor activity (eg, an Ab against factor VIII or factor V) or the activity of the procoagulant phospholipid used in certain coagulation test systems (the lupus anticoagulant). Rarely, circulating anticoagulants are not Abs but glycosaminoglycans with heparin-like anticoagulant activity arising from their ability to increase antithrombin III reactivity. These heparin-like anticoagulants are found mainly in patients with multiple myeloma or other hematologic malignancies.
Occasionally, Abs are not circulating anticoagulants, since they do not neutralize a clotting factor activity. These Abs usually cause bleeding by binding prothrombin. Although the prothrombin-antiprothrombin complex retains its coagulant activity in vitro, it is rapidly cleared from the blood in vivo, with resultant acute hypoprothrombinemia.
A common anticoagulant first described in patients with SLE was logically called the lupus anticoagulant; subsequently it was recognized in patients with a variety of disorders, often as an unrelated finding. The phenomenon of anticoagulation results when Abs react with epitopes on anionic phospholipids (including the phospholipids used in the PTT and in specific clotting factor assays based upon the PTT technique). The following pattern of test results is found: a prolonged PTT that fails to correct with a 1:1 mixture of the patient's and normal plasma, a normal or minimally prolonged PT, and a nonspecific depression of those clotting factors measured by a PTT technique (factors XII, XI, IX and VIII). Some patients will also have a false-positive VDRL test for syphilis, in which the phospholipid cardiolipin is used as the antigen, and most patients will have evidence of Abs reacting with cardiolipin by a more sensitive radioimmunoassay technique.
Although the anticoagulant interferes with the function of procoagulant phospholipid in clotting tests in vitro, patients with only the lupus anticoagulant do not bleed excessively. Apparently, the anticoagulant does not interfere with the function of procoagulant phospholipid on cell surfaces in vivo. Paradoxically, however, for an unknown reason, patients with the lupus anticoagulant are at increased risk for thrombosis, which may be either venous or arterial. If such a patient experiences a thrombotic episode, long-term prophylaxis with anticoagulant therapy should be seriously considered. Repeated abortions in the first trimester, possibly related to thrombosis of placental vessels, have also been reported occasionally.
A subset of patients with the lupus anticoagulant develop a second Ab, which was described earlier the non-neutralizing Ab to prothrombin that induces hypoprothrombinemia and these patients do bleed abnormally. Hypoprothrombinemia is suspected when the screening tests reveal a long PT in addition to the long PTT and is confirmed by a specific assay. Treatment with corticosteroids is indicated; usually the PT returns rapidly to normal and bleeding is controlled.
Hepatic artery occlusion is uncommon but can be caused by thrombosis, embolism, abdominal trauma or surgical ligation. The occlusion may produce an ischemic infarct of the liver, but results are unpredictable because of individual differences in hepatic vasculature and the extent of collateral circulation.
Previous studies have reported autoantibodies to nuclear lamin B1 in a small number of selected SLE patients. However, the clinical associations of anti-lamin B1 are unclear.
To date there exist no diagnosis test for the clinical predisposition and/or prognosis of coagulation disorders, such as thrombosis.
It would be highly desirable to know the distribution, the titer and the clinical significance of high titers of IgG anti-lamin B1 autoantibodies in a large number of unselected and well-characterized SLE patients, disease controls and normal controls.
SUMMARY OF THE INVENTION
One aim of the present invention is to provide the clinical significance of high titers of IgG anti-lamin B1 autoantibodies in a subset of SLE patients, disease controls and normal controls.
In accordance with an embodiment of the present invention there is provided a method to determine predisposition to coagulation disorders in a patient, which comprises the step of determining the presence or absence of anti-lamin B1 (aLB1) antibodies in a biological sample of the patient; wherein absence of aLB1 antibodies is indicative of a predisposition to coagulation disorders; and wherein presence of aLB1 antibodies is indicative of a low risk of coagulation disorders incidence.
The method may further comprises determining the presence or absence of lupus anticoagulant (LA) antibodies in the biological sample; wherein presence of LA and aLB1 antibodies is indicative of a low risk of coagulation disorders incidence; and wherein presence of LA antibodies with absence of aLB1 antibodies is indicative of a predisposition to coagulation disorders.
Such a determining step may be effected with LA and LB1 antigen.
The coagulation disorders include, without limitation, thrombosis.
The biological sample include, without limitation, a serum sample.
In accordance with another embodiment of the present invention there is provided a method for diagnosis of lupus or of non-lupus in a patient, which comprises determining the presence of anti-lamin B1 antibodies (aLB1) in a biological sample of the patient, wherein presence of aLB1 is indicative of a lupus diagnosis.
In accordance with another embodiment of the present invention there is provided a method of treatment of coagulation disorders in a patient, which comprises administering a aLB1 compound which mimics activity of anti-lamin B1 (aLB1) anti
Raymond Yves
Senécal Jean-Luc
Chan Christina
Haddad Maher
Ogilvy Renault France Côté
Universite de Montreal
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