Antiphospholipid antibody is an autoantibody made against one's own normal body chemicals. Lupus patients as a rule have many autoantibodies,
the best known of which are the antinuclear antibodies (ANA) made against the centre parts of the body's cells and anti-DNA antibodies, which react with the major chemical contained in the nuclei. Antiphospholipid
antibodies are similar in that they react with a type of fat (lipid) that contains phosphate. The outside walls of all the body's cells are made of phospholipids. This type of fat is not the type which is responsible
for weight. (Having antiphospholipid antibodies will not help you lose weight.) Cardiolipin is merely one of several normal body phospholipids. Historically, anticardiolipin antibody was the first antiphospholipid
antibody described; but because antibodies can be found against many other phospholipids, the general term antiphospholipid antibody is now preferred to the more historical term, anticardiolipin antibody. There is
probably no difference between anticardiolipin antibody and antibodies to the other phospholipids.
Physicians may use slightly different definitions to diagnose APS. In general, you need to have a positive blood test
for either the Lupus Anticoagulant or the Anticardiolipin Antibody. In addition to the blood tests you must also have one of the following criteria:
1) A history of blood clots, thrombosis
2) Low Platelet Count, thrombocytopenia
3) Recurrent pregnancy loss
There may also be skin, heart and nervous system abnormalities.
Actual questions asked by patients
What are antiphospholipid antibodies?
are several kinds of antiphospholipid antibodies. The most widely measured are the lupus anticoagulant and anticardiolipin antibody. These antibodies react with phospholipid, a type of fat molecule that is part of the
normal cell membrane. Lupus anticoagulant and anticardiolipin antibody are closely related, but are not the same antibody. This means that someone can have one and not the other. There are other antiphospholipid
antibodies, but they are not commonly measured.
How common are antiphospholipid antibodies?
As with other autoantibodies (antibodies directed against one's self) in lupus, the antiphospholipid antibodies can come and go in any individual patient. It turns out that
there are many ways to measure these antibodies, and different methods may not always give the same result. For example, in different studies, 8 to 65 percent of people with lupus have the lupus anticoagulant, and 25 to
61 percent have anticardiolipin antibody. These antibodies can also be found in people who do not have lupus. For example, two percent of young women have anticardiolipin antibody. These antibodies were first discovered
in people who have lupus, but it is not necessary to have lupus to have these antibodies. In fact, in most studies, over 50% of people with these antibodies do not have lupus. We do not understand why a person's immune
system begins to manufacture these antibodies.
Why are antiphospholipid antibodies important?
The presence of both the lupus anticoagulant and anticardiolipin antibody is increased in lupus patients who have had thrombotic (blood clotting) complications such as deep
venous thrombosis ("thrombophlebitis"), stroke, gangrene, and heart attack. Studies suggest that the presence of these antibodies may also increase the future risk of thrombotic events. Anticardiolipin
antibody has been found to be increased in pregnant women with lupus who have had miscarriages. The combination of thrombotic problems, miscarriages, and a low platelet count has been called the "Antiphospholipid
Antibody Syndrome." It is not necessary to have lupus to have the Antiphospholipid Antibody Syndrome. It is important for doctors to realize this and to check people who have had a stroke, heart attack, or
miscarriage for no known reason to see if they have these antibodies.
Antiphospholipid antibodies interfere with the normal function of blood vessels, both by causing narrowing and irregularity of the vessel (called "vasculopathy"), and by causing clots in the vessel (called
"thrombosis"). These blood vessel problems can then lead to complications such as stroke, heart attack, and miscarriage.
How do doctors test for antiphospholipid antibodies?
Blood tests are used to identify antiphospholipid antibodies. Specialized tests which measure blood
clotting (coagulation tests) are used to find the lupus anticoagulant. The activated partial thromboplastin time (aPTT) is a widely available blood clotting test that is often used. If the aPTT is normal, more sensitive
coagulation tests should be done to test for the lupus anticoagulant. These more sensitive tests include the modified Russell viper venom time (RVVT), the platelet neutralization procedure (PNP), and the kaolin clotting
time (KCT). If the clotting test is prolonged (the number of seconds that it takes the blood to clot is longer), the physician will suspect that the lupus anticoagulant is present. This is confusing, because even though
the blood takes longer to clot in the test tube, the blood actually clots more easily in the person's body.
The anticardiolipin antibody is measured in an ELISA test. There are many classes of anticardiolipin antibody (IgG, IgM, IgA). It is possible to test for all of these antibody
classes at once or the physician may wish to test for each one separately. The IgG type of anticardiolipin antibody is the type that is most often associated with complications. Sometimes, there are technical
difficulties with the IgM test, making it more difficult to interpret the results of this test. Some lupus patients with very high IgM anticardiolipin antibody have a problem called hemolytic anemia, in which their
immune system attacks their red blood cells.
antibodies can come and go, how often should doctors check for them in lupus patients?
There are no current recommendations on the timing of repeat tests. Certainly the antiphospholipid antibodies should be checked in people who have had thrombotic
problems, miscarriages, or low platelet counts.
What is the treatment for a person who has antiphospholipid antibodies?
If a person has the lupus anticoagulant
or anticardiolipin antibody, but has never had a thrombotic complication, treatment is not currently recommended. If a patient has had a thrombotic complication and has these antibodies, treatment may depend on where
the clot (thrombosis) occurred. In general, treatment consists of "thinning" the blood to prevent future clots, using either aspirin or warfarin (Coumadin).
How successful is treatment in people who have had a thrombosis (clot) in association with these
who had initially been treated with aspirin have had a second episode of thrombosis and have then been treated with warfarin (Coumadin). A few of these patients had a second episode of thrombosis while on warfarin.
However, treatment with warfarin appears to be successful overall. The length of time that this treatment is necessary is unclear. Many physicians recommend long-term or even life-long treatment to prevent future
episodes of thrombosis.
If a woman has antiphospholipid antibodies and is pregnant, how is it treated?
If the woman has antiphospholipid antibodies and is pregnant for the first time, or has had normal pregnancies in the past, no treatment may be advised. However, if the woman
has had miscarriages in the past, several different treatment regimens are available, including aspirin, Prednisone, and/or subcutaneous shots of a blood thinner called Heparin. Pregnancies in women with
antiphospholipid antibodies are considered to be "high risk pregnancies."
It is necessary for the obstetrician or gynecologist to work closely with the rheumatologist or other physician who evaluates a woman with miscarriages for antiphospholipid
antibodies. Miscarriages, especially early in pregnancy, are not rare. Women who have had multiple miscarriages should be checked to see if they have antiphospholipid antibodies as part of an overall obstetric
evaluation for causes of miscarriage.
How successful is treatment in
people with lupus who have had a miscarriage in association with these antibodies?
The treatment of pregnant women with antiphospholipid antibodies to prevent a possible miscarriage is not well understood at the current time. Some women are helped by
combinations of aspirin, Prednisone, and/or subcutaneous heparin, whereas other women continue to have miscarriages even when they are taking these medications. Subcutaneous heparin is less likely than Prednisone to
cause diabetes and an increase in blood pressure during pregnancy. Other treatments, including plasmapheresis or intravenous gammaglobulin, may be considered in individual cases.