Accuracy of anticardiolipin antibodies in identifying a history of thrombosis among patients with systemic lupus erythematosus

Renal thrombotic microangiopathy associated with anticardiolipin antibodies in hepatitis C-positive renal allograft recipients

Hepatitis C virus (HCV) infection has been associated with de novo or recurrent membranoproliferative glomerulonephritis and acute transplant glomerulopathy in transplanted kidneys. Recently, anticardiolipin antibodies (ACA) have been linked with chronic HCV infection. A few reports have suggested an association between ACA and renal allograft thrombosis. This study examines the clinical and pathologic features of HCV-positive renal allograft recipients at our institution. From 1990 to 1996, 379 kidney transplants were performed. We identified 18 recipients (4.8%) with HCV-positive serology pretransplant. Determination of IgG and IgM ACA was performed by enzyme-linked immunosorbent assay, using pretransplant sera. Among the 18 patients, five patients presented with biopsy-proven de novo renal thrombotic microangiopathy (RTMA), occurring 5 to 120 d (median, 14 d) after transplant. No differences in pretransplant characteristics were observed between patients with (n = 5) or without (n = 13) RTMA. All five patients had a positive ACA test (either IgG or IgM titer > 2 SD above normal), compared with only one of 13 patients without RTMA. The mean value for IgG ACA was significantly higher in the RTMA patients than in patients without RTMA (22.9 +/- 14.1 versus 6.9 +/- 4.9 IgG phospholipid units, P = 0.02); however, there were no significant differences in IgM ACA titers. Rheumatoid factor and complement C4 levels were normal in pretransplant sera of patients with RTMA. Patients with RTMA had their cyclosporine withdrawn (four of five) or the dose was decreased (one of five), and one of five underwent plasmapheresis. Four of five patients died within 5 yr after transplant, compared with no deaths in the other 13 patients. Finally, as a control group, seven HCV-negative renal allograft recipients who presented with RTMA/hemolytic uremic syndrome during the same time period were found to have normal ACA values (IgG or IgM). RTMA associated with ACA in HCV-positive renal allograft recipients may represent a new clinical entity. The occurrence of this syndrome may have deleterious consequences for patient and graft survival.

Neurological manifestations of antiphospholipid antibody syndrome

Thrombosis, thrombocytopenia, recurrent fetal loss and a variety of non-thrombotic neurological disorders have all been associated with antiphospholipid antibodies (aPL). Cerebral ischemia associated with aPL is the most common arterial thrombotic manifestation. Depression, cognitive dysfunction, depression and psychosis have all been associated with aPL. The presumed pathophysiologic mechanism underlying these manifestations is thought to be a result of cerebral ischemia in some, but not all cases. Seizures, chorea and transverse myelitis all appear to be associated with aPL. An interaction between aPL and central nervous system cellular elements rather than aPL-associated thrombosis seems to be a more plausible mechanism for these clinical manifestations. Migraine on the other hand, does not appear to be associated with aPL in either lupus or non-lupus populations. Neuroimaging studies show an increased frequency of brain abnormalities in patients with aPL, but none appear to be specific. The best treatment strategy for preventing neurological manifestations of aPL is not fully defined. For thrombotic manifestations, both antiplatelet and anticoagulant therapies have been suggested. In some patients, immunosuppressant therapy has been used. For non-thrombotic manifestations, some combination of immunosuppressant therapy and symptomatic treatment may be warranted.

Diagnosis of the antiphospholipid syndrome: a proposal for use of laboratory tests

The presence of antiphospholipid (aPL) antibodies has been associated with thrombosis, pregnancy loss and thrombocytopenia in the antiphospholipid syndrome (APS). The anticardiolipin and the lupus anticoagulant tests are frequently used to detect aPL antibodies. The anticardiolipin ELISA utilizes cardiolipin coated on polystyrene plates as antigen and is a very sensitive test but lacks specificity, since it can be positive in a number of infectious (such as syphilis, HIV) and autoimmune diseases other than APS. In an effort to improve specificity, new ELISA techniques that employ alternative antigens (such as beta2-glycoprotein 1, particularly when coated onto oxidized microtiter plates or mixture of phospholipids) have been developed. Several investigators have reported that these new assays enable more specific determination of aPL antibodies and thus can be used more reliably for the diagnosis and confirmation of APS. This article examines the results of those studies, including data that shows correlations of these assays with clinical manifestations of APS, and proposes a new protocol for the use of laboratory tests in the diagnosis of APS.

Towards improved criteria for the antiphospholipid syndrome

A workshop to be held in Sapporo will attempt to upgrade criteria for the antiphospholipid syndrome (APS). These criteria should probably be based on a scoring system using both clinical and biological items. Clinical criteria could be categorized between 'major', that is thrombosis or obstetrical criteria, and 'minor', to be selected among livedo, heart valve lesions, chorea, adrenal hemorrhage, thrombocytopenia, and others. A similar approach could be proposed for biological criteria, with persistent strong LA, high IgG aCL or antibodies to beta2GPI as major criteria if the workshop accepts antibodies directed to co-factors as APS criteria. Minor criteria could include IgM aCL, low/medium IgG aCL, and VDRL. Whether anti-prothrombin, anti-oxidised LDL, and M5 anti-mitochondrial antibodies should be added to the minor criteria, is open to discussion. In our mind, other parameters should be taken into account such as: young age--a method to avoid the questionable exclusion of arteriosclerosis in cases of arterial thrombosis--and the presence of personal and/or first-degree familial features of auto-immunity. Lastly, a differential diagnosis section is probably needed.

Anticardiolipin antibodies and hepatic artery thrombosis after liver transplantation

BACKGROUND

Hepatic artery thrombosis (HAT) remains a devastating complication after liver transplantation. Various factors have been implicated in the pathogenesis of HAT, such as clotting abnormalities, increased hematocrit, and technical complications, but the role of anticardiolipin antibodies has not been evaluated. We investigated the possible association between HAT and anticardiolipin antibodies in adult patients who underwent liver transplantation.

METHODS

Seven patients with HAT after orthotopic liver transplantation, 28 liver recipients without HAT, and 35 normal blood donors were evaluated. Determination of IgM and IgG anticardiolipin antibodies was performed by enzyme-linked immunosorbent assay using pretransplant serum from all allograft recipients. Clinical information was obtained from chart review. Fisher's exact test and Wilcoxon rank sum test were used for statistical analysis, and all P-values were two-tailed.

RESULTS

Overall, 22 of 35 (63%) liver recipients had a positive anticardiolipin antibody test (either IgG or IgM titer >4 SD from the normal controls). The test was positive in 7 liver recipients (100%) with HAT compared with 15 out of 28 patients (54%) without HAT (P=0.031). As compared with liver recipients without HAT, patients with HAT also tended to have a higher mean anticardiolipin titer of IgG and IgM and a lower pretransplant platelet count; however, these differences were not significant.

CONCLUSIONS

Our findings indicate that anticardiolipin antibodies are frequently elevated in patients with liver failure and may contribute to the pathogenesis of HAT after liver transplantation. Other potential consequences of anticardiolipin antibodies in end-stage liver disease remain to be determined.

IgG anticardiolipin antibody titer > 40 GPL and the risk of subsequent thrombo-occlusive events and death. A prospective cohort study

BACKGROUND

Anticardiolipin antibodies (aCL) have been associated with an increased risk of stroke and thrombo-occlusive events. Little is known about the influence of aCL on recurrent thrombo-occlusive events.

METHODS

Consecutively identified patients (n = 132) with focal cerebral ischemia [stroke = 112, transient ischemic attack (TIA) = 20] harboring aCL of at least 10 GPL units at the time of their index event were prospectively followed to estimate the effect of aCL titer on time to and risk of subsequent thrombo-occlusive events (stroke, TIA, deep venous thrombosis, pulmonary embolism, myocardial infarction) and death. On the basis of prior literature, we divided patients into those with aCL < or = 40 GPL (n = 111; mean age, 63 +/- 14 years; mean follow-up, 1.95 years) and those with aCL > 40 GPL (n = 21; mean age, 54 +/- 20 years; mean follow-up, 1.50 years).

RESULTS

There was no difference between groups for prevalence of hypertension, diabetes mellitus, cigarette smoking, atrial fibrillation, prior TIA, or sex. The GPL > 40 group was younger (54 +/- 20 versus 63 +/- 14 years; P = .055), had more prior strokes [9/21 (48%) versus 27/111 (20%); P = .030], more frequent subsequent thrombo-occlusive events and death [15/21 (71%) versus 51/111 (48%); P = .030], and a shorter median time (years) to event (0.15 versus 0.61, log rank P = .005). The risk ratio for recurrent event and death with GPL > 40 obtained from Cox proportional hazards models, adjusted for prior strokes, prior TIAs, hypertension, diabetes mellitus, atrial fibrillation, and cigarette smoking was 1.9 (95% confidence interval, 1.0 to 3.5; P = .051).

CONCLUSIONS

Our data suggest that subsequent thrombo-occlusive events and death after focal cerebral ischemia associated with IgG aCL may occur sooner and more frequently with GPL > 40.

Thrombotic syndromes and autoimmune diseases

Maintenance of blood flow involves the dynamic interactions between the endothelium, circulating cellular components, coagulation factors, and factors involved in fibrinolysis. Autoantibodies, inflammatory cytokines and other undefined triggers in a genetically predisposed person may lead to an imbalance in the equilibrium between the various hemostatic pathways resulting in potentially catastrophic thrombotic events. This article reviews the clinical manifestations and treatment of selected, potentially life-threatening thrombotic syndromes that may occur in association with autoimmune diseases. Special mention is made of thrombotic events associated with Behçet's syndrome.

Treatment of neurologic complications of antiphospholipid antibody syndrome

Thrombosis associated with antiphospholipid antibodies (aPL) occurs in both venous and the arterial circulation. The most common arterial thrombo-occlusive event is cerebral infarction. We briefly review treatment strategies aimed at patients with cerebrovascular disease and aPL. Besides general treatment issues, we discuss primary prevention and secondary prevention. Most regimens include antithrombotics or immune modulation. Prospective studies (currently underway) are required to better estimate the rate of recurrent thrombo-occlusive events on standardized therapy before one therapy can be recommended over another with reasonable evidence.

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.

1996 diagnostic and classification criteria for the antiphospholipid/cofactors syndrome: a "mission impossible'?

Due to recent acquisitions, diagnostic criteria for the antiphospholipid/cofactors syndrome need to be improved. In the absence of a "common biological denominator", the best approach should be based on a scoring system mixing clinical and immunological items. APS might be composed of different biological subsets characterized by antibodies directed to various cofactors. Among clinical subsets, the categorization between "primary" and SLE-related APS may be difficult to achieve. Contrasting with the innumerable conditions associated with the presence of aPL, the diversity of "true" secondary APS should probably be restrained. Attempts at establishing correlations between clinical and biological APS subsets will require further studies.

The lupus anticoagulant/antiphospholipid syndrome

Lupus anticoagulants and anticardiolipin antibodies have been strongly associated with the risk of thrombosis, recurrent fetal loss, thrombocytopenia, and a number of other clinical manifestations that together have been referred to as the antiphospholipid syndrome. Despite growing evidence of the significance of this relationship, the pathogenetic mechanisms involved are largely unknown. Recent data suggest strongly that lupus anticoagulants (LACs) and anticardiolipin antibodies (ACAs) are antibodies to protein-phospholipid complexes rather than to phospholipids, as had originally been thought, and that other protein-phospholipid complexes, not recognized by standard assays for LACs or ACAs, may also exist in patients with the antiphospholipid syndrome. Although very recent experimental data may lead to new therapeutic approaches in this syndrome, at present we can only deal with the thrombotic risk by the use of long-term anticoagulation. This chapter reviews current methods of diagnosis, concepts of pathogenesis, and the basis for an approach to anticoagulation in patients at risk for thrombosis or other manifestations of the antiphospholipid syndrome.