[New targets of antiphospholipid antibodies]

Antiphospholipid-related chorea

Chorea is a movement disorder which may be associated with immunologic diseases, in particular in the presence of antiphospholipid antibodies (aPL). Choreic movements have been linked to the isolated presence of plasmatic aPL, or to primary, or secondary antiphospholipid syndrome. The highest incidence of aPL-related chorea is detected in children and females. The presentation of chorea is usually subacute and the course monophasic. Choreic movements can be focal, unilateral, or generalized. High plasmatic titers of aPL in a choreic patient can suggest the diagnosis of aPL-related chorea; neuroimaging investigation does not provide much additional diagnostic information. The most relevant target of aPL is β2-glycoprotein I, probably responsible for the thrombotic manifestations of antiphospholipid syndrome. Etiology of the movement disorder is not well understood but a neurotoxic effect of aPL has been hypothesized, leading to impaired basal ganglia cell function and development of neuroinflammation. Patients affected by aPL-related chorea have an increased risk of thrombosis and should receive antiplatelet or anticoagulant treatment.

[Relative value of different antiphospholipid antibodies detected in a department of internal medicine: retrospective study of 124 patients]

PURPOSE

The value of antiphospholipid antibodies (aPL) detected in the sera of the patients of an Internal Medicine department is not univocal and is still much debated. To test the contribution of such new markers, we reviewed the records of patients having antiphospholipid antibodies detected between 1996 and 1997.

METHODS

One hundred and twenty four patients, having at least one of these two aPL: lupus anticoagulant (LA), anticardiolipin antibodies (aCL), or one of these two anti-proteins: anti-beta 2glycoprotéin I antibodies (anti-beta 2GPI) or anti-prothrombin antibodies (aPT), were studied. LA was detected by a PTT-LA technique and aCL, anti-beta 2GPI and aPT by ELISA-sandwich techniques. For each patient we recorded sex, age, personal and familial history of thrombosis, fetal losses and systemic disease, the reason of aPL detection, the final diagnosis, activated partial thromboplastin time (aPTT), platelets count and type of aPL.

RESULTS

The population was composed of 77 women (62%) and 47 men (38%) with a mean age of 54 years [12-92 years]. A thrombocytopenia was strongly correlated to aCL presence (OR = 6.15 et p = 0.03). The reason of aPL detection was venous thrombosis, recurrent fetal losses, systemic disease, infectious disease or fortuitous discovery of a prolonged aPTT. The final diagnosis was a systemic disease in 57% of cases, an infectious disease in 14.5%, a thrombosis in 4.5% and a neoplasia in 3%. LA was detected in 54% of patients, aCL in 39.5%, anti-beta 2GPI in 23% and aPT in 31%. No relationship between the aPTT value and the type of aPL could be established.

CONCLUSION

Our study shows that familial histories of venous thrombosis or systemic disease are useful to enhance antiphospholipid antibodies detection; that LA is mostly associated to systemic and infectious diseases; that aCL and anti-beta 2GPI are predominant in case of venous thrombosis and that thrombocytopenia has to enhance aCL detection and the discussion about a possible APS.

Antibodies and vascular involvement in inflammatory joint disease: clinical relevance

The vascular endothelium is a common target of inflammatory joint disease. Autoimmune diseases including rheumatoid arthritis, systemic lupus erythematosus, and Sjögren's syndrome can be responsible for a spectrum of vascular disorders that encompasses vasculitis, thrombosis and/or atheroma associated with the antiphospholipid syndrome, and vascular damage caused by cryoglobulin deposition. These mechanisms can coexist, particularly in lupus patients. Joint disease is sometimes the presenting manifestation in primary vasculitis. Autoantibodies are detectable in most patients with vascular involvement and inflammatory joint disease. They are not merely markers for vascular involvement: in vitro and in vivo data suggest that some autoantibodies may contribute to the genesis of endothelial lesions, together with other factors. For instance, evidence of pathogenic effects has been found for antineutrophil cytoplasmic antibody (ANCA), most notably with antimyeloperoxidase or antiproteinase-3 specificity, in small-vessel vasculitides (Wegener's granulomatosis, Churg-Strauss syndrome, and microscopic polyangiitis); for immune complexes, particularly those containing cryoglobulins, in vasculitides secondary to CTDs; and for circulating anticoagulant and anticardiolipin antibodies, above all anti-beta2-glycoprotein I, in antiphospholipid syndrome. Antibodies to annexin V, modified lipoproteins, and endothelial cells may be of interest; their clinical relevance is unclear, however, and no standardized assays are available, so thatthese antibodies are not looked for in everyday practice. When deciding which antibody tests should be performed in a given patient, the circumstances surrounding the onset of the vasculopathy should be borne in mind. In patients with previous CTD, the tests are selected based on the diagnosis. In contrast, in a patient with no previous diagnosis, a vasculopathy can be either primary or secondary to undiagnosed CTD or to antiphospholipid syndrome: consequently, a broader array of tests is needed in this situation.