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Biomedical subjects

M A Khamashta

Publications and source records attributed to M A Khamashta.

At least 91 records · Page 5Linked to original sources
PubMed2001

The value of IgA antiphospholipid testing for diagnosis of antiphospholipid (Hughes) syndrome in systemic lupus erythematosus.

OBJECTIVE: It is recognized that the presence of IgG and IgM anticardiolipin antibodies (aCL) and lupus anticoagulant (LAC) is associated with thrombosis in patients with antiphospholipid syndrome (APS). Some reports have shown that testing for IgA anticardiolipin and anti-beta2-glycoprotein antibodies (anti-beta2-GPI) provides extra diagnostic help in patients with APS, while other authors could not support this data. We designed this cross sectional study to determine the prevalence of IgA aCL, anti-beta2-GPI, and antiprothrombin antibodies and to study their clinical significance in a large cohort of patients with systemic lupus erythematosus (SLE). METHODS: This study comprised 134 SLE patients (126 women; median age 37.5 yrs, range 16-72). The median duration of the disease was 9 years, range 0.1-38. Of these, 55 (41%) had a history of thrombotic events: 22 (40%) presented an arterial event, 22 (40%) a venous event, and 11 (20%) both arterial and venous events. Of 49 women who had been pregnant, 18 (37%) gave a history of recurrent pregnancy loss. Thrombocytopenia was present in 14/127 patients (11%). Forty patients (30%) were diagnosed as APS secondary to SLE, 23 (17%) had IgG/M aCL and/or LAC without clinical features of APS, and 71 (53%) were SLE patients who were repeatedly negative for IgG/M aCL or LAC. IgG, IgM, IgA aCL and anti-beta2-GPI were detected by ELISA. Antibodies directed to prothrombin were detected by 2 ELISA using prothrombin coated on irradiated plates (aPT) and phosphatidylserine/prothrombin complex (aPS/PT) as antigen. RESULTS: IgA aCL were found in 18/134 (13%) patients. Of these, 3 (17%) had IgA aCL as well as IgG/M aCL, and 2 (11%) had IgG/M aCL and anti-beta2-GPI. Of the 18 patients positive for IgA aCL, 8 were also positive for LAC. Of these, one (5%) patient had IgA aCL as well as other isotype of aCL, and 7 (39%) patients had both aCL and anti-beta2-GPI. None of these patients had binding of IgA aPT or aPS/PT. Of the entire group of 18 patients, 5 (28%) had IgA aCL as the sole aPL. Four of 5 of these patients were diagnosed as SLE but had no antiphospholipid (aPL) related clinical manifestations. We found no association between the presence of IgA aCL and clinical manifestations of APS. IgA anti-beta2-GPI were found in 8/134 (6%) patients. Of these, one (12.5%) had IgA anti-beta2-GPI as well as IgG/M anti-beta2-GPI and aCL. Of the 8 patients positive for IgA anti-beta2-GPI, 6 (75%) were also positive for LAC. Of these, one (12.5%) patient presented with IgA anti-beta2-GPI along with other isotypes of aCL, and 4 (50%) patients with aCL and other isotype of anti-beta2-GPI. One patient (12.5%) had IgA anti-beta2-GPI along with LAC only, and one patient (12.5%) who was diagnosed as SLE had no aPL related clinical manifestation but had IgA anti-beta2-GPI as the sole aPL. CONCLUSION: IgA aCL and anti-beta2-GPI are found in SLE, usually along with IgG and/or IgM isotypes. Testing for IgA aCL and anti-beta2-GPI is not a helpful screening test and does not contribute to the recognition of APS in SLE. IgA aPT and aPS/PT are not present in patients with SLE, therefore there is no need to test for these antibodies.

Abortion, Habitual↗
PubMed2000

Antiphospholipid antibodies affect trophoblast gonadotropin secretion and invasiveness by binding directly and through adhered beta2-glycoprotein I.

OBJECTIVE: To investigate the in vitro ability of antiphospholipid antibodies (aPL) to bind human trophoblast cells and to affect gonadotropin secretion and invasiveness. METHODS: Antiphospholipid antibody IgG from women with recurrent miscarriages, beta2-glycoprotein I (beta2GPI)-independent IgG aPL human monoclonal antibody (mAb) (519), and IgM anti-beta2GPI human mAb (TMIG2) were investigated for their binding to trophoblasts cultured for various amounts of time, their ability to affect invasiveness of Matrigel-coated filters, and their release of human chorionic gonadotropin (hCG). RESULTS: Polyclonal IgG aPL, as well as mAb 519 and TMIG2, bound to trophoblasts, the highest binding being found when cells displayed the greatest amount of syncytium formation. TM1G2 binding was found to be betaGPI dependent. Both polyclonal and monoclonal aPL, but not the controls, significantly reduced hCG release and Matrigel invasiveness. CONCLUSION: These findings suggest that aPL recognition of both anionic PL and adhered beta2GPI on trophoblast cell structures might represent a potential pathogenetic mechanism for defective placentation in women with the antiphospholipid syndrome.

Anions↗
PubMed2000

Association of antiphosphatidylserine/prothrombin autoantibodies with HLA class II genes.

OBJECTIVE: To investigate the associations between HLA class II genes and antiphosphatidylserine/prothrombin antibodies (aPS/PT) in a group of British caucasoid patients with antiphospholipid antibodies (aPL). METHODS: This study included 82 patients with aPL. IgG aPS/PT were detected in sera using enzyme-linked immunosorbent assays. HLA-DQB1, DQA1, and DRB1 genotypes were determined by polymerase chain reaction using sequence-specific primers. All results were compared with 177 matched healthy control subjects. RESULTS: IgG aPS/PT were present in 41 of 82 patients (50%). The frequencies of DQB1*0301/4, DQB1*0604/5/6/7/9, and DRB1*1302 alleles were increased in patients with aPS/PT compared with controls. To minimize the interference of the association between anti-beta2-glycoprotein I (anti-beta2GPI) and HLA, patients with anti-beta2GPI were excluded from further analyses, and only HLA-DQB1*0301/4 remained significant compared with controls (odds ratio [OR] 2.75, 95% confidence interval [95% CI] 1.2-6.5, P < 0.03). In the haplotype analysis, HLA-DQB1*0301/4;DQA1* 0301/2;DRB1*04 was significantly increased in patients with IgG aPS/PT compared with controls (OR 4.75, 95% CI 1.72-13.10, P = 0.0063). CONCLUSION: The HLA-DQB1*0301/4;DQA1*0301/ 2;DRB1*04 haplotype and its components may influence the production of aPS/PT in the antiphospholipid syndrome, which partly explains the correlation between the lupus anticoagulant and DQB1*03.

Adolescent↗
PubMed2000

Natural immune response involving anti-endothelial cell antibodies in normal and lupus pregnancy.

OBJECTIVE: To determine whether immunoglobulins with affinity for the vascular endothelium displayed any distinguishing behavior during normal and systemic lupus erythematosus (SLE) pregnancy. We also attempted to verify whether isotype expression of anti-endothelial cell antibodies (AECA) would have any predictive value for pregnancy outcome. METHODS: Sera from 38 pregnant patients with SLE, 68 normal pregnant women, and 84 nonpregnant healthy controls were studied. IgM- and IgG-AECA were determined by cellular enzyme-linked immunosorbent assay using fixed cultured human umbilical vein endothelial cells. RESULTS: A significantly higher level of IgM-AECA was found during normal pregnancy compared with that in healthy nonpregnant controls (mean +/- SD 39 +/- 12% versus 21 +/- 12%; P < 0.0001). Most pregnant patients with SLE did not have increased titers of IgM-AECA, but instead had levels similar to those found in healthy nonpregnant controls (23 +/- 12%; P not significant). The lowest levels of IgM-AECA in lupus pregnancy were associated with preeclampsia (odds ratio 16, P < 0.005). Conversely, IgG-AECA levels were significantly higher in the serum of normal pregnant women and pregnant SLE patients than in the serum of healthy nonpregnant controls (24 +/- 7% and 24 +/- 14% versus 9 +/- 7%; P < 0.0001). CONCLUSION: Our results indicate that an active immune response occurs during pregnancy. This response involves increased activity of AECA, suggesting a role of autoantibodies as a possible contributing factor toward fetal tolerance. Our observations further indicate that impaired immune regulation, such as diminished levels of serum IgM-AECA detected in SLE patients, might contribute to the impaired reproductive function commonly found in SLE.

Adult↗
PubMed2000

Primary prevention of thrombosis in subjects with positive antiphospholipid antibodies.

A major cause of stroke, as well as other arterial and venous thromboembolic disease has been identified-the presence of antiphospholipid antibodies (aPL). Now it is possible to identify individuals positive for aPL and still free of thrombosis. The tests to measure aPL have been standardized (aCL by ELISA and LA by coagulometric assays) and they are routinely performed in patients with SLE and other connective tissue diseases and women with recurrent pregnancy loss. However, very little is known about the risk of thrombosis in individuals positive for aPL but still free of thrombosis. Should these individuals receive any treatment? If so, which one?

Animals↗
PubMed2000

Antiphospholipid antibodies and the endothelium.

This article reviews current understanding of the relationship between antiphospholipid antibodies and the endothelium. In vitro antiphospholipid antibodies produce endothelial cell activation. Clinical data in this area are scanty and worthy of future research, which could lead to new therapies in the management of antiphospholipid syndrome.

Antibodies, Antiphospholipid↗
PubMed2000

Impaired estrogen priming of progesterone receptors in uterus of MRL/MP-lpr/lpr mice, a model of systemic lupus erythematosus (SLE).

Estrogens exacerbate the autoimmune disease SLE and progesterone is immunoprotective. Estrogens increase synthesis of progesterone receptors (PR) and it is hypothesized that this physiological balance may be impaired in SLE. To test this, cytosolic PR were measured in hypothalamus, thymus and uterus from 6-week-old female ovariectomized BALB/c and MRL/MP-lpr/lpr mice 48 h after s.c. injection of estradiol benzoate (3.2 microg/0.1 ml; OB) in peanut oil or 0.1 ml peanut oil alone. PR were measured using [(3)H]ORG 2058, which does not bind to corticosteroid-binding globulin (CBG), and bound and free ligand were separated using minicolumns of Sephadex LH20 at 0 degrees C. PR were measured in cytosols from hypothalamus and uterus of oil-treated BALB/c mice, but were undetectable in thymus, whereas receptors were measurable in all three tissues of MRL mice. There was a significantly greater priming effect of OB on PR in uterus of BALB/c mice, but not in hypothalamus, and PR became detectable in thymus cytosols from BALB/c mice. Also, the apparent affinity of the binding reaction between [(3)H]ORG 2058 and PR was significantly higher than those measured in other tissues in hypothalamic cytosols of both strains. These results suggest that there is an impairment of estrogen priming of progesterone receptors in uterus and perhaps thymus of MRL mice.

Animals↗
PubMed2000

Antiphospholipid (Hughes) syndrome in systemic lupus erythematosus.

APS is found in 20% to 35% of patients with SLE. PAPS and secondary APS have similar features and aPL specificities. The clinical course of the secondary syndrome is independent of the activity and severity of lupus, but the presence of APS worsens the prognosis of patients with lupus. Some features of SLE may result from thrombosis in patients with APS; thus, these patients require anticoagulation rather than corticosteroids. Novel preliminary classification criteria for APS were formulated during a postconference workshop held in Sapporo, Japan, following the Eight International Symposium on Antiphospholipid Antibodies. Treatment of APS remains empirical because of limited controlled prospective data. There is strong evidence that patients with aPL-associated thrombosis are subject to recurrences and require prophylactic therapy. APS is a treatable cause of recurrent fetal loss in women with SLE. The treatment of choice is anticoagulation with heparin, either standard unfractionated heparin or LMWH. One of the main reasons for the improving outcomes in APS pregnancies is closer obstetric surveillance.

Antiphospholipid Syndrome↗
PubMed2000

Fine specificity of autoantibodies to calreticulin: epitope mapping and characterization.

Extracellular calreticulin (CRT) as well as anti-CRT antibodies have been reported in patients with various autoimmune disorders and CRT has been implicated in 'epitope spreading' to other autoantigens such as the Ro/SS-A complex. In addition, antibodies against parasite forms of the endoplasmic reticulum chaperone, CRT, have been found in patients suffering from onchocerciasis and schistosomiasis. In this study, we screened sera for anti-CRT antibodies from patients with active and inactive systemic lupus ertythematosus (SLE) and primary or secondary Sjögren's syndrome. Approximately 40% of all SLE patients were positive for anti-CRT antibodies. The antigenic regions of CRT were determined using full length CRT and fragments of CRT prepared in yeast and Escherichia coli, respectively. Synthetic 15mer peptides corresponding to the major autoantigenic region of CRT (amino acids 1-289), each one overlapping by 12 amino acids, were used to map the B cell epitopes on the CRT protein recognized by autoimmune sera. Major antigenic epitopes were found to be associated with the N-terminal half of the protein in 69% of the SLE sera from active disease patients, while the C-domain was not antigenic. Major epitopes were found to be reactive with antibodies in sera from SLE patients with both active and inactive disease, spanning different regions of the N and P-domains. Sera from both healthy and disease controls and primary Sjögren's syndrome patients were non-reactive to these sequences. Limited proteolysis of CRT with two major leucocyte serine proteases, elastase and cathepsin G, demonstrated that an N-terminal region of CRT is resistant to digestion. Interestingly, some of the epitopes with the highest reactivity belong to the fragments of the protein which bind to C1q and inhibit complement activation. Whether C1q association with CRT is a pathological or protective interaction between these two proteins is currently under investigation.

Adult↗
PubMed2000

The anti-phospholipid antibody syndrome (Hughes syndrome): therapeutic aspects.

Despite the enormous amount of work focused on the pathogenesis and clinical manifestations of the Hughes or anti-phospholipid syndrome (APS), there is little published on management. Usually, the diagnosis of APS is made after the first thrombotic event, when a thrombophilia screen is performed. These patients have a high risk of recurrent thromboses and current therapy centres on the use of thromboprophylaxis with warfarin. However, a number of clinical questions keep recurring: do arterial and venous thrombosis require the same intensity of anti-coagulation? When should warfarin be stopped? Should patients who develop thrombosis when other risk factors (oral contraceptive pill, prolonged resting etc.) are present be treated like those without any risk factors but the presence of anti-phospholipid antibodies (aPL)? How to manage a patient with recurrent thrombosis despite a high intensity anti-coagulation (International normalized ratio (INR) between 3.0-4.0)? Since many of the patients with aPL are fertile women, a substantial group of patients are diagnosed after recurrent pregnancy loss. Low-dose aspirin for those patients without previous thrombosis and aspirin plus heparin for patients with a history of thrombotic events are the current therapeutic options. However, some questions remain unanswered: does the addition of heparin to low-dose aspirin in women with first trimester recurrent miscarriage but without previous thrombosis improve foetal outcome over and above aspirin alone? Which is the best therapeutic regime during pregnancy for patients with aPL-associated stroke? When should high-dose intravenous gammaglobulin be considered? Finally, very little is known about the risk of thrombosis in individuals positive for aPL but still free of thrombosis. Should these individuals receive any treatment? If so, which one? In this review we attempt to address some of these questions taking into account available data from retrospective and prospective studies and our own clinical experience.

Abortion, Habitual↗
PubMed2000

Non-steroidal anti-inflammatory drugs as a possible cause for reversible infertility.

OBJECTIVE: To highlight the possible association between infertility and treatment with long-term non-steroidal anti-inflammatory drug (NSAIDs). NSAIDs act mainly through the inhibition of cyclooxygenase, the enzyme that catalyses the synthesis of prostaglandins, which are essential mediators of ovulation, implantation and placentation of the conceptus. METHODS: Case reports of four women suffering from severe arthritis, on long-term NSAIDs and undergoing extensive investigation and treatment for infertility. RESULTS: During the last 2 yr, four out of five women with severe arthritis and difficulty conceiving were counselled to stop NSAIDs, and they successfully conceived shortly after the withdrawal of NSAIDs. CONCLUSION: NSAIDs, used largely for the treatment of rheumatological conditions, may be responsible for some cases of infertility.

Adult↗
PubMed2000

Can neurologic manifestations of Hughes (antiphospholipid) syndrome be distinguished from multiple sclerosis? Analysis of 27 patients and review of the literature.

Hughes (antiphospholipid) syndrome (APS) can mimic multiple sclerosis (MS). We analyzed the clinical, laboratory, and imaging findings of MS-like expression in a cohort of patients with APS in an attempt to identify parameters that might differentiate the 2 entities. We studied 27 patients who were referred to our unit with the diagnosis of probable or definite MS made by a neurologist. All patients were referred to our lupus clinic because of symptoms suggesting an underlying connective tissue disease, uncommon findings for MS on magnetic resonance imaging (MRI), atypical evolution of MS, or antiphospholipid antibody (aPL) positivity. aPL, antinuclear antibody (ANA), anti-dsDNA, and anti-extractable nuclear antigen (ENA) antibodies were measured by standard methods. MRI was performed in every patient and compared with MRI of 25 definite MS patients who did not have aPL. An index severity score was calculated based on the size and number of increased signal intensity areas in MRI. In the past medical history, 8 patients with primary APS and 6 with APS secondary to systemic lupus erythematosus (SLE) had had symptoms related to these conditions. Neurologic symptoms and physical examination of the patients were not different from those common in MS patients. Laboratory findings were not a useful tool to distinguish APS from MS. When MRI from APS patients was compared globally with MRI from MS patients, MS patients had significantly increased severity score in white matter (p < 0.001), cerebellum (p = 0.035), pons (p < 0.015), and when all areas were taken together (p < 0.001). Patients with APS had significantly increased scores in the putamen (p < 0.01). No differences were noticed in the degree of atrophy. When taken individually, MRI from APS patients could not be distinguished from MRI from MS patients. Most of the patients with primary APS showed a good response to oral anticoagulant treatment. In patients with secondary APS, the outcome was poorer. Hughes syndrome (APS) and MS can be difficult to distinguish. A careful medical history, a previous history of thrombosis and/or fetal loss, an abnormal localization of the lesions in MRI, and the response to anticoagulant therapy might be helpful in the differential diagnosis. We believe that testing for aPL should become routine in all patients with MS.

Adolescent↗
PubMed2000

Determination of autoantibodies to annexin XI in systemic autoimmune diseases.

Annexin XI, a calcyclin-associated protein, has been shown to be identical to a 56,000 Da antigen recognized by antibodies found in sera from patients suffering from systemic autoimmune diseases. In this work hexahistidine-tagged recombinant annexin XI (His6- rAnn XI) was used as antigen in ELISA experiments for determination of autoantibodies to annexin XI in sera of patients with systemic rheumatic autoimmune diseases. Immunoblotting with HeLa cell extract and with His6-rAnn XI as antigen was used for confirmation of positive ELISA results. We found eleven anti-annexin XI positive sera (3.9%) out of 282 sera from patients with systemic rheumatic diseases. The highest number of annexin XI positive sera were found in primary antiphospholipid syndrome (3/17), and in subacute lupus erythematosus (1/6), while lower frequencies of positive sera were found in patients with systemic sclerosis (5/137), rheumatoid arthritis (1/21), and systemic lupus erythematosus (1/58). Sera from healthy donors and patients with chronic infections were negative, except for one Salmonella typhimurium antibody positive serum. Autoantibodies to annexin XI were found to relate to thrombosis, but not to other clinical or laboratory features. A relation between antibodies to annexins and thrombosis has so far only been known for annexin V.

Adult↗