J. Cohen et al., PATHOGENIC NATURAL ANTICARDIOLIPIN ANTIBODIES - THE EXPERIENCE FROM MONOCLONAL GAMMOPATHY, Clinical and experimental immunology, 97(2), 1994, pp. 181-186
Anti-cardiolipin antibodies (ACA) were detected in 19% of sera from pa
tients with monoclonal gammopathies (MG). ACA were purified from the s
era of patients with MG. One of the IgG-ACA was found to be monospecif
ic with high affinity for cardiolipin, and to carry a pathogenic ACA I
d (1.10). Active immunization of naive BALB/c mice with the purified I
gG-ACA was followed by production in the mice of sustained high titres
of ACA, associated with prolonged activated partial thromboplastin ti
me (APTT) (61 +/- 14s versus 31 +/- 2s in control mice; P < 0.001) and
thrombocytopenia (468 000 +/- 224 000/mm(3) versus 994 000 +/- 92 000
/mm(3) in controls; P < 0.001). The titres of other autoantibodies (e.
g. anti-DNA, anti-histones), although being high after immunization, d
ecreased rapidly and were undetected after 1 month following the boost
injection. The mice immunized with the IgG-ACA exhibited low fecundit
y (36% of mice became pregnant versus 62% observed in the group immuni
zed with control IgG). The pregnant mice had increased resorption rate
(the equivalent of fetal loss in the human) of 52 +/- 8% (versus 5 +/
- 4% in the control group). The mean (+/-s.d.) embryo and placental we
ights in mice with anti-phospholipid syndrome (APLS) were significantl
y lower compared with the mice injected with control IgG (682 +/- 304
mg and 102 +/- 12 mg versus 1303 +/- 105 mg and 145 +/- 8 mg, respecti
vely; P < 0.001). Serum monoclonal immunoglobulins having autoantibody
activity may be regarded as an expansion of clones producing natural
autoantibodies. Our results confirm the pathogenic role of natural ACA
in the pathogenesis of the anti-phospholipid syndrome.