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| Dr. William Matzner, Simi Valley, California |
Characterization of Antiphospholipid Antibodies in Women with Recurrent Spontaneous Abortions
This is an excerpt of an article originally published
in The Journal of Reproductive Medicine and was co-authored by Dr.
William Matzner. The full article is available here.
Introduction
It is estimated that approximately 40% of women with
systemic lupus eythematosus (SLE) will have antibodies to negatively charged
phospholipid, with reported ranges of 30% to 70% having suffered thrombotic
events. In 1986 a group of women without known autoimmune diseases who had
recurrent spontaneous abortions (RSA) or vascular thrombosis was described.
These women had antibodies to a negatively charged phospholipid, cardiolipin,
with high titers primarily of the IgG isotype. The mechanisms of action defined
were platelet membrane damage, endothelial wall injury, inhibition of
prostacyclin and inability to activate protein C; thus, RSA would occur via
placental vascular insufficiency. In 1985 Harris showed that anticardiolipin
antibody (aCL) bound equally to all negatively charged phospholipids. Subsequent
studies that addressed issues of antiphospholipid antibodies (aPLs) therefore
assumed nondifferential binding or concentrated only on aCL.
In 1985 Lockshin et al demonstrated that the level of aCL
was useful as an early predictor of fetal distress or death in patients with
SLE. Recent work has implicated antiphosphoserine antibody, predominantly of
the IgM isotype, as an inhibitor of placental formation and a cause
of RSA.
In the study described below, aPLs were characterized in a
group of women who have suffered recurrent fetal loss.
Materials and Methods
Patients
Three hundred fifty-two patients with a history of two or
more consecutive spontaneous pregnancy losses were evaluated. They were
premenopausal (aged 2145; mean, 39), and all were recruited between March 1991
and May 1992. Women with collagen vascular disease were excluded. Phospholipid
antibodies of the IgM and IgG isotypes to cardiolipin, phosphoethanolamine,
phosphoinositol, phosphoserine, phosphatidic acid and phosphoglycerol were measured.
Controls
The control group consisted of 43 people without known
immunologic or rheumatologic diseases. None of the women in the control group
had suffered RSA or any other thromboembolic phenomena.
aPL Assay
The assay used has been described previously. Briefly, six
purified phospholipids were coated separately on Immulon 2 96-well
enzyme-linked immunosorbent assay plates overnight. The plates were blocked the
next day with phosphate-buffered saline (PBS) and 10% newborn calf serum for
two hours and then washed (Biotech BT500) in PBS.
Fifty microliters of patient serum was added to the
appropriate wells and incubated for one hour followed by a second wash with PBS. Alkaline phosphatase-conjugated goat
antihuman IgG and IgM was incubated for an hour, then washed in PBS. Sigma
Substrate 104 in diethanolamine buffer was added to the wells and incubated for
30 minutes at 37°C, and
the reaction was stopped with NaOH. The trays were read in a BioTech BT2000
microtiter reader at 405 nm. Delta optical densities were calculated by
subtracting out the background (wells without the phospholipid antigens).
The
results were compared to the mean of the delta optical densities for the
control group. Positivity was defined as 3 SD above the mean of the controls.
Results
The prevalence of one or more antibodies to any of the six
phospholipids was 59.1% (208/352) in the study population. In the control
group, only 4.6% (2/43) had a positive aPL.
Two hundred eight patients had 439 antibodies of the IgG or
IgM isotype to the phospholipids. The most frequently identified aPLs in order
of decreasing frequency were to phosphoserine, 20.5% (90/439); phosphoethanolamine,
19.1% (84/439); phosphatidic acid, 18.7% (82/439); cardiolipin, 16.4% (72/439);
phosphoglycerol, 16.2% (71/439); and phosphoinositol, 9.1% (40/439). In the two
positive controls there were 2 anitibodies, both of the IgG isotype, 1 each to
cardiolipin and phosphatidic acid. In the RSA patients, 75.2% (330/439) of the
antibodies were of the IgM isotype, and 24.8% (109/439) were of the IgG isotype.
Of all of the patients studied, 18.2% (64/352) had aCL
versus 40.9% (144/352) with any other combination excluding aCL. Of all the
patients with any aPL, 30.8% (64/ 208) were to cardiolipin. Eighty-one patients
had antibodies to only one epitope: 37.0% (30/81) were to phosphoethanolamine,
14.8% (12/81) to phosphatidic acid and 16.0% (13/81) to cardiolipin. Of this
group, 83.9% (68) were IgM and 16.1% (13) were IgG isotypes.
The remainder of the patients (132) had antibodies to
multiple epitopes. They had 358 antibodies of the IgG or IgM isotype. In this
group, in order of decreasing frequency, were antibodies to phosphoserine,
22.9% (82/ 358); phosphatidic acid, 19.6% (70/358); phosphoglycerol, 18.2%
(65/358); cardiolipin, 16.5% (59/358); phosphoethanolamine, 15.1% (54/ 358);
and phosphoinositol, 7.8% (28/358). In these patients, 73.2% (262/358) of the
antibodies were of the IgM and 26.8% (96/358) of the IgG isotype.
About William L.
Matzner, M.D., PhD, FACP
Dr.
William Matzner works in the area of healthcare economics consulting at
Healthcare Analytics, LLC, in California. He graduated Phi Beta Kappa from
Stanford University. He received his M.D. with Honors from Baylor College of
Medicine. In 1988, he was the Solomon Scholar for Resident Research at Cedar
Sinai Medical Center. Dr. Matzner subsequently was awarded a PhD in Neuro
Economics from Claremont Graduate University. He is board certified in Internal
Medicine and Palliative Medicine. He has researched and published extensively
on the issue of reproduction and immunology in medical literature. He has been
in private practice since 1989, specializing in Reproductive Immunology and
Internal medicine.
Website: https://drwilliammatzner.com
Consulting Website: https://healthcareanalytics.biz
William Matzner, MD (Simi Valley, California), has been practicing medicine since 1989, Internal Medicine and Reproductive Immunology. M.D. with Honors from Baylor College of Medicine.
