Antibodies to thromboplastin in systemic lupus erythematosus: isotype distribution and clinical significance in a series of 92 patients

Autoantibodies associated with reproductive failure

Autoimmune factors are involved in some of the cases of reproductive failure. These factors entail several autoantibodies, especially in patients having systemic lupus erythematosus (SLE) or the antiphospholipid syndrome (APS). These autoantibodies include mainly antibodies directed to phospholipid such as cardiolipin, phosphatidylserine, phosphatidylethanolamine or phospholipids binding glycoproteins such as b2glycoprotein-I, annexin V, prothrombin and protein-Z. There are also some other autoantibodies directed to laminin-I, thromboplastin, mitochondrial antibodies of the M5 type, corpus luteum, prolactin, poly (ADP-ribose), thyroglobulin and more, which were also found in SLE or APS patients with reproductive failure. Moreover, the presence of additional autoantibodies directed to actin, enolase, cubilin and others, needs further investigation to support a firm association to reproductive failure in women. Future studies are likely to help to determine and expand the number of autoantibodies screened in these patients, as well as by the use of proteomics technology, to determine peptides resembling the epitope specificities associated with the specific clinical manifestations.

Antiphospholipid antibody-mediated reproductive failure in antiphospholipid syndrome

The association of elevated titers of circulating antiphospholipid (anti-PL) Abs in antiphospholipid syndrome (APS) and reproductive failure is well established in the literature. The clinical features include recurrent abortions at various stages, including implantation, placentation in the first trimester, miscarriages in the second and third trimesters, intrauterine growth retardation, preeclampsia with placental insufficiency and growth restrictions, arterial and venous thrombosis, and possibly also infertility. APS-mediated recurrent pregnancy loss and other features of reproductive failure might result from diverse autoimmune factors, inflammation, involving different mechanisms, which encompass pathogenic anti-PL Abs. Herein, we discuss the association of anti-PL Abs with reproductive failure with special emphasis on antiphospholipid autoantibodies characterizing APS. This association is evident from either human studies or murine models.

Autoantibody explosion in systemic lupus erythematosus: more than 100 different antibodies found in SLE patients

OBJECTIVE

Description of the various autoantibodies that can be detected in patients with systemic lupus erythematosus (SLE).

METHODS

A literature review, using the terms "autoantibody" and "systemic lupus erythematosus", was conducted to search for articles on autoantibodies in SLE, their target antigens, association with disease activity, or other clinical associations.

RESULTS

One hundred sixteen autoantibodies were described in SLE patients. These include autoantibodies that target nuclear antigens, cytoplasmic antigens, cell membrane antigens, phospholipid-associated antigens, blood cells, endothelial cells, and nervous system antigens, plasma proteins, matrix proteins, and miscellaneous antigens. The target of autoantibody, the autoantigen properties, autoantibody frequencies in SLE, as well as clinical associations, and correlation with disease activity are described for all 116 autoantibodies.

CONCLUSIONS

SLE is the autoimmune disease with the largest number of detectable autoantibodies. Their production could be antigen-driven, the result of polyclonal B cell activation, impaired apoptotic pathways, or the outcome of idiotypic network dysregulation.

Multiple autoantibodies associated with autoimmune reproductive failure

PURPOSE

Autoimmune factors are involved in some of the cases of reproductive failure. The aim of this paper is to discuss the association between autoantibodies and reproductive failure.

METHODS

Literature review of autoantibodies associated with reproductive failure.

RESULTS

Several autoantibodies were found in association with such clinical manifestations, mainly in patients having systemic lupus erythematosus or the antiphospholipid syndrome. These autoantibodies include "classical" antiphospholipid antibodies such as anticardiolipin, anti-beta2-glycoprotein-I, antiphosphatidylserine, and antiphosphatidylethanolamine. There are also some "nonclassical" antiphospholipid antibodies directed to prothrombin, thromboplastin, or mitochondrial antibodies of M5 type, which were also found in patients with reproductive failure. Moreover, animal models as well as some human studies support a role for other autoantibodies in these clinical manifestations including antihyroglobulin, antilaminin-1, anti-corpus luteum, antiprolactin, anti-poly(ADP-ribose), and lymphocytotoxic antibodies.

CONCLUSIONS

Even though there is not enough data currently to support a firm association between some of these autoantibodies and reproductive failure, future studies are likely to help us determine and expand the number of autoantibodies screened in these patients.

Hughes (antiphospholipid) syndrome. Clinical features

Hughes (antiphospholipid) syndrome is a noninflammatory autoimmune disease. The most critical pathologic process is thrombosis, which results in most of the clinical features suffered by these patients. Recurrent thrombosis together with an adverse pregnancy history and the presence of antiphospholipid antibodies defines the syndrome.

Do antiphospholipid antibodies interfere with tissue factor pathway inhibitor?

This study was conducted to investigate whether antiphospholipid antibodies (APA) can interfere with the phospholipid-dependent inhibition of coagulation exerted by tissue factor pathway inhibitor (TFPI). Eleven patients with APA and eleven healthy controls matched for age and gender were enrolled. Blood samples were drawn before and 5 minutes after an intravenous injection of unfractionated heparin 5000 IE, which is known to cause TFPI release in healthy individuals. The preheparin samples showed significantly higher TFPI free antigen levels in the APA positive patients than in the controls (21.7 vs. 14.2 ng/ml, p = 0.03). TFPI activity as measured in a chromogenic substrate assay also was higher in patients, but this difference was not statistically significant (1.13 vs. 1.01 U/ml, p = 0.2). The TFPI levels showed a considerable rise in both patients and controls after heparin injection. In both assays, the postheparin levels were significantly higher in patients than in controls (TFPI antigen: 179 vs. 153 ng/ml, p = 0.05; TFPI activity: 3.26 vs. 2.51 U/ml, p = 0.03). A modified diluted prothrombin time assay (dPT) was used to measure TFPI anticoagulant activity. In this assay, samples from the patients with the strongest effect of lupus anticoagulants (LAs) on preheparin coagulation times showed little or no increase after heparin injection. This result may reflect an inhibition of TFPI anticoagulant activity by strong LAs. In conclusion, we have found that patients with APA have higher TFPI amidolytic activity/antigen level both before and after heparin stimulation of TFPI release. These observations do not explain the higher thrombotic risk in these patients but may reflect an upregulated tissue factor activity, which has been demonstrated in these patients. TFPI anticoagulant activity, however, as measured in a dPT assay, may be inhibited by strong LAs.