Association of antiphospholipid antibodies with central nervous system disease in systemic lupus erythematosus

A young woman with SLE: diagnostic and therapeutic challenges

The presence of antiphospholipid antibodies, especially of the IgG isotype and in high titre, is associated with additional complications in patients with SLE. The thrombocytopaenia and cerebral events in the patient described are likely to have been linked to her lupus anticoagulant. However, the antibody and anticardiolipin antibodies are not necessarily synonymous and indeed we did not detect anticardiolipin antibodies in the patient, although her sister had them. It is likely that they represent overlapping sets of immunoglobulins. The production and analysis of further such antibodies, as described in this review, is awaited urgently. Much effort is also being expanded on identifying the precise targets for these antibodies. In a very recent report Hörkkö et al have shown that these antibodies may be directed against epitopes of oxidized phospholipids. The management of patients with complex disorders such as described here remain a challenge, although in the short term the patient's major locomotor, neurological, dermatological and haematological problems have been controlled. Long-term problems including impaired fertility and osteoporosis remain to be faced.

Cerebral lupus vasculopathy. Mechanisms and clinical relevance

The most common neuropathological findings in SLE are a small vessel cerebral vasculopathy and microinfarcts. These findings may reflect the end result of repeated episodes of acute inflammation in the small vessels in the brain. There is experimental support for the local Shwartzman reaction as a paradigm to explain some of the CNS manifestations in SLE. Activation or "priming" of cerebral microvascular endothelial cells by anticardiolipin antibodies or other immunoglobulins in concert with intravascular activation of the complement system may combine to elicit leukothrombosis in the brain. Therapies aimed at inhibiting leukocyte-endothelial cell interactions in the brain may be of use in CNS lupus.

Neurological dysfunction and hyperactive behavior associated with antiphospholipid antibodies. A mouse model

Antiphospholipid antibodies (aPL) have been associated with various neurological manifestations, but the underlying mechanism has not been elucidated. We assessed mice with induced experimental antiphospholipid syndrome (APS) for neurological and behavioral changes. After immunization with monoclonal human anticardiolipin antibody (H-3), female BALB/c mice developed elevated levels of circulating anti-negatively charged phospholipids (aPL), anti-beta2-glycoprotein I (abeta2GPI), and anti-endothelial cell antibodies (AECA), along with clinical manifestations of APS like thrombocytopenia and fetus resorption. APS mice were impaired neurologically and performed several reflexes less accurately compared to the controls, including placing reflex (P < 0.05), postural reflex (P < 0.05), and grip test (P = 0.05). The APS mice also exhibited hyperactive behavior in an open field, which tests spatial behavior (P < 0.03), and displayed impaired motor coordination on a rotating bar. aPL in combination with abeta2GPI and AECA is probably involved in the neurological and behavioral defects shown in mice with experimental APS.

Prevalence and signification of antinuclear and anticardiolipin antibodies in patients with epilepsy

PURPOSE

To determine the prevalence of autoantibodies in patients with epilepsy and to find a possible relationship between antinuclear antibodies (ANA) and/or anticardiolipin (aCL) antibodies and epilepsy.

PATIENTS AND METHODS

One hundred sixty-three consecutive, unselected patients followed at the Centre Saint-Paul, a French medical center specialized in epilepsy, were included in the study. IgG and IgM class aCL antibodies were measured by an enzyme-linked immunosorbent assay (ELISA). IgG class ANA was detected by an indirect immunofluorescence technique with Hep2 cells as the substrate. Sera from 100 healthy blood donors, matched for age and sex, were used as controls.

RESULTS

In 31 sera, IgG class a aCL antibodies were detected at a value higher than 17 GPL unit (19%, P = 0.0003); 10 of them had a value higher than 35 GPL unit. IgM class aCL antibodies were not detected at a significant value. For 6 of the 31 sera, there was a beta 2-glycoprotein I dependence. None of the patients with aCL antibodies in the serum had a past history of deep venous or arterial thrombosis. ANA were detected in the sera from 41 patients (25%, P < 0.005). The presence of autoantibodies in the serum was not statistically dependent on the type of epilepsy, the kind of antiepileptic drug, or the age or sex of the patients.

CONCLUSIONS

Our study suggests that there is a relationship between epilepsy and aCL antibodies, even in the patients without systemic lupus erythematosus. Large prospective studies are needed to define the role of the aCL antibodies and ANA in pathophysiology of epilepsy.

The clinical significance of antiphospholipid antibodies

The antiphospholipid syndrome is defined as the association between the presence of antiphospholipid antibodies, detected as anticardiolipin antibodies and/or lupus anticoagulant, and a history of either arterial or venous thrombosis and/or recurrent pregnancy loss. Because thrombosis may occur in virtually any organ system, diagnosing the antiphospholipid syndrome and taking appropriate anticoagulation measures are important considerations in all medical specialties. Antiphospholipid antibody-associated thrombosis tends to recur. Antithrombotic prophylaxis to prevent recurrences is therefore needed. Prophylaxis in individuals with circulating antiphospholipid antibodies who have no history of thrombosis is still controversial. Although direct evidence for a pathogenetic role of antiphospholipid antibodies in the development of thrombosis is still lacking, recent studies suggest that it is causative rather than coincidental. New insights on the possible mechanisms leading to thrombosis were provided by the discovery of the serum cofactor (beta2-GPI), a coagulation inhibitor which is required for binding of anticardiolipin antibodies to cardiolipin. More recently, patients with antiphospholipid antibodies were found to possess autoantibodies directed against other coagulation factors, including prothrombin, protein C and protein S. Future studies should clarify whether these different antigenic specificities are associated with particular clinical events and assess the risk of thrombosis associated with the presence of antiphospholipid antibodies in asymptomatic individuals.

Management of thrombosis in the antiphospholipid syndrome

Optimal management of patients with the antiphospholipid syndrome (APS) remains a problem. There is now good evidence that those with thrombosis will be subject to recurrences and require long-term, possibly lifelong, oral anticoagulation. Steroids and immunosuppressive drugs aiming at a reduction of the antibody levels have not provided long-term benefit. Only prospective and controlled clinical trials can give a definitive answer to the optimal thrombotic prophylaxis in patients with the APS.

Neurological aspects of antiphospholipid antibody syndrome

Antiphospholipid antibodies (aPL) have been associated with a variety of neurological disorders, mostly linked to focal neuroparenchymal ischemia or infarction. Cerebral ischemia associated with the antiphospholipid syndrome (APS) occurs at a younger age than typical atherothrombotic cerebrovascular disease, is often recurrent, and high positive GPL values are usually linked to the presence of a lupus anticoagulant. When other features of the syndrome are not present and cerebral ischemia occurs only associated with anticardiolipin immunoreactivity, there appears to be no discerning features of these patients unless GPL > 40 for which recurrent thrombo-occlusive events appear to occur more frequently. Other neurological manifestations associated with aPL include cerebral venous sinus thrombosis, ocular ischemia, dementia, including ischemic encephalopathy, and chorea. The role of aPL in migrainous events is controversial and may not play a role in recent, large case-controlled studies. Most seizures in patients harboring aPL are associated with focal brain infarction.

Elevated levels of anticardiolipin antibodies and epilepsy in lupus patients

To examine the association between anticardiolipin (aCL) antibodies and epilepsy, we investigated the serum titers of aCL antibodies in a total 252 systemic lupus erythematosus (SLE) patients recruited in a prospective study. Twenty-one cases with epilepsy which were not attributable to any causes other than SLE were identified after being followed-up for five years. The clinical manifestations were recorded and blood samples were tested for the presence of aCL antibodies (IgG, IgM and IgA isotypes). Among 21 patients with epilepsy, 12 (57.1%), 2 (9.5%) and 2 (9.5%), respectively, had elevated baseline serum levels of IgG, IgM and IgA aCL antibodies. There was a dose-response relationship between risk of seizure and the baseline serum level of aCL antibodies (P < 0.01). The odds ratio of developing seizure were 3.7 for those who had a high level of aCL antibodies compared with those without a detectable level of aCL antibodies as the referent. Our results indicate that epilepsy as a primary neuropsychiatric event among lupus patients is associated with a high titer of aCL antibodies.