Thrombosis in systemic lupus erythematosus: striking association with the presence of circulating lupus anticoagulant.

The lupus anticoagulant was found in the plasma of 31 of 60 patients with systemic lupus erythematosus and other connective tissue disorders (mixed connective tissue disease, systemic vasculitis, polyarteritis nodosa, primary sicca syndrome, discoid lupus, Behcet''s syndrome, and systemic sclerosis). Strong associations were found with biological false positive seroreaction for syphilis and thrombocytopenia. The most striking association, however, was with the high prevalence of thrombosis. This tendency to thrombosis was independent of disease activity of systemic lupus erythematosus. The lupus anticoagulant appears to be a useful marker for a subset of patients with systemic lupus erythematosus at risk for the development of thromboembolic complications.     

Diffuse large cell lymphoma presenting as a sacral mass and lupus anticoagulant

A 67-year-old gentleman presented to Yale-New Haven Hospital (YNHH) for assessment of a supratherapeutic INR and sacral lesion. Hematologic workup revealed elevated ESR, PT, INR, PTT, and CRP, mixing studies that failed to correct, and a positive Russell Viper Venom Test (RVVT), which confirmed the presence of lupus anticoagulant (LA), a subtype of antiphospholipid syndrome (APA). Pathology of the patient's sacral lesion revealed diffuse large B-cell lymphoma. This case provides insight into the association between APA and lymphoid neoplasm. The patient's unique presentation is in marked contrast to other reports of APA and lymphoid malignancy, which are typically associated with elevated PTT, normal PT, minimal extranodal disease, and potential thrombotic complications. Further, treatment with Rituximab-CHOP chemotherapy led to excellent clinical response with tumor remission and normalization of PT and PTT.     

Recurrent stent thrombosis associated with lupus anticoagulant due to renal cell carcinoma

A case is presented of recurrent stent thrombosis unexplained by angiographic appearance, which subsequently revealed a diagnosis of antiphospholipid syndrome secondary to renal cell carcinoma.     

Degos' disease: association with anticardiolipin antibodies and the lupus anticoagulant.

A woman presented with multiple cerebral thromboses and skin lesions characteristic of Degos'' disease. Her serum contained high titres of anticardiolipin antibodies and showed lupus anticoagulant activity, both known to be strong markers of a thrombotic tendency in systemic lupus erythematosus. This finding may have therapeutic implications for this usually fatal disease.     

Kinetics of prothrombin-mediated binding of lupus anticoagulant antibodies to phosphatidylserine-containing phospholipid membranes: an ellipsometric study

Antiphospholipid antibodies interact with phospholipid membranes via lipid binding plasma proteins, mostly, prothrombin and beta(2)-glycoprotein I. Using ellipsometry, we characterized prothrombin-mediated binding of lupus anticoagulant (LA) positive IgG, isolated from patients with antiphospholipid syndrome, to phosphatidylserine (PS)-containing membranes. LA IgG did not bind to membranes in the absence of prothrombin, but addition of prothrombin resulted in high-affinity binding of prothrombin-LA IgG complexes; half-maximal binding was attained at IgG and prothrombin concentrations of 10 microg/mL and 4 nM, respectively. Adsorption to membranes containing 10-40 mol % PS revealed that membrane-bound rather than solution-phase prothrombin determines the adsorption kinetics. Depletion of prothrombin and LA IgG from the solution results in rapid desorption which is strongly inhibited by addition of prothrombin but not of LA IgG. Prothrombin-mediated adsorption of monovalent Fab1 fragments prepared from patient LA IgG was negligible, indicating that monovalent interaction between prothrombin and LA IgG is weak. The kinetics of adsorption and desorption indicate that divalent binding of LA IgG to prothrombin at the lipid membrane occurs.     

Some plasmin-induced antibodies bind to cardiolipin, display lupus anticoagulant activity and induce fetal loss in mice

The combined presence of anti-phospholipid Ab (aPL), thrombosis, and/or fetal loss is recognized as the antiphospholipid syndrome (APS). aPL include anti-cardiolipin Ab (aCL) and/or lupus anticoagulants (LAC, detected as Ig that prolong certain in vitro phospholipid (PL)-restricted blood clotting tests); both aCL and LAC are the diagnostic Ab for APS. Studies show that aPL represent a heterogeneous group of Ab, which recognize various PL, PL-binding plasma proteins, and/or PL-protein complexes. Recently, we found that five of seven patient-derived IgG monoclonal aCL react with thrombin, activated protein C, and plasmin. All three proteins are trypsin-like serine proteases (SP), and are highly homologous in their catalytic domains. Importantly, among these SP autoantigens, the reactive aCL bind to plasmin with the highest affinity, suggesting that plasmin may serve as a major driving autoantigen for some aCL in approximately 30% of APS patients who are positive for IgG anti-plasmin Ab. To test this hypothesis, we immunized BALB/c mice with human plasmin and analyzed immune sera for aCL activity and reactivity with relevant SP. We found that some immune sera displayed aCL activity and/or bound to test SP. Subsequently, eight mAb were obtained and studied. The results revealed that one mAb displayed the aCL and the LAC activities and induced fetal loss when injected into pregnant mice. Immunohistological analyses of placentas revealed extensive deposits of activated C3 components. Combined, these data demonstrate that plasmin may serve as a driving Ag for some pathogenic aPL.     

Familial systemic lupus erythematosus: a comparison of clinical manifestations and antibody presentation in three ethnic groups.

The serologic and clinical features of patients from pedigrees multiplex for systemic lupus erythematosus (SLE) were evaluated among three ethnic groups: Hispanics, African-Americans and European-Americans. Data were obtained from a registry of 123 pedigrees, composed of 4 Hispanic, 40 African-American and 79 European-American pedigrees. All patients met at least four criteria for the diagnosis of SLE per the American College of Rheumatology. Clinical information was obtained through review of the medical records and questionnaires completed by the participants. Ethnicity by self-identification was found to be an important factor influencing the prevalence of serologic results and clinical features. Anti-nRNP occurred more frequently in African-Americans (45.7%) than in European-Americans (7.5%) or Hispanics (0%) (p<0.0000001), as did anti-Sm (18.5% vs 1.6% and 0%, respectively) (p<0.000001). Malar rash, photosensitivity and oral ulcers were most frequent in the Hispanic population while proteinuria and leukopenia predominated in the African-American population. Arthritis and lymphopenia were present in a similar proportion in all ethnic groups. These results show that many of the ethnic differences known for isolated cases of SLE are also present in familial cases of SLE.     

Anti-beta 2 glycoprotein I antibodies in systemic lupus erythematosus: a marker of thrombosis associated with a circulating anticoagulant]

An ELISA technique for the detection of anti-beta 2 glycoprotein I (beta 2gp I) antibodies was developed. Among 47 systemic lupus erythematosus patients, 17 had anti-beta 2gp I antibodies. These antibodies were statistically associated with anticardiolipin antibodies, lupus anticoagulant and thrombosis. Out of 18 patients with anticardiolipin antibodies without anti-beta 2gp I antibodies or lupus anticoagulant, only one had thrombosis (due to nephrotic syndrome). Therefore the presence of anti-beta 2gp I antibodies is a new immunologic marker of lupus patients with thrombosis. In addition, we propose that anti-beta 2gp I antibodies may be directly responsible for lupus anticoagulant activity.     

Familial hyperaldosteronism

Primary aldosteronism (PAL) may be as much as ten times more common than has been traditionally thought, with most patients normokalemic. The study of familial varieties has facilitated a fuller appreciation of the nature and diversity of its clinical, biochemical, morphological and molecular aspects. In familial hyperaldosteronism type I (FH-I), glucocorticoid-remediable PAL is caused by inheritance of an ACTH-regulated, hybrid CYP11B1/CYP11B2 gene. Genetic testing has greatly facilitated diagnosis. Hypertension severity varies widely, demonstrating relationships with gender, affected parent's gender, urinary kallikrein level, degree of biochemical disturbance and hybrid gene crossover point position. Analyses of aldosterone/PRA/cortisol 'day-curves' have revealed that (1) the hybrid gene dominates over wild type CYP11B2 in terms of aldosterone regulation and (2) correction of hypertension in FH-I requires only partial suppression of ACTH, and much smaller glucocorticoid doses than those previously recommended. Familial hyperaldosteronism type II is not glucocorticoid-remediable, and is clinically, biochemically and morphologically indistinguishable from apparently sporadic PAL. In one informative family available for linkage analysis, FH-II does not segregate with either the CYP11B2, AT1 or MEN1 genes, but a genome-wide search has revealed linkage with a locus in chromosome 7. As has already occurred in FH-I, elucidation of causative mutations is likely to facilitate earlier detection of PAL and other curable or specifically treatable forms of hypertension.