Value of IgA anticardiolipin and anti-beta2-glycoprotein I antibody testing in patients with pregnancy morbidity

OBJECTIVE: To study the prevalence of IgA antiphospholipid antibodies, particularly anticardiolipin antibodies (aCL) and anti-beta(2)-glycoprotein I (abeta(2)GPI), in a cohort of patients with pregnancy morbidity. PATIENTS AND METHODS: Serum samples from four groups of patients were studied by an in house enzyme linked immunosorbent assay (ELISA). Group I: 28 patients with primary antiphospholipid syndrome (PAPS) (median age 32.5 years, range 25-34). Twelve patients had a history of thrombosis. All were positive for IgG/M aCL or lupus anticoagulant (LA), or both. Group II: 28 patients with unexplained pregnancy morbidity (median age 35 years, range 23-48). Seven had history of thrombosis. Nine patients were positive for IgG/M aCL. None from this group fulfilled Sapporo criteria for APS. Group III: 28 patients with systemic lupus erythematosus (SLE) (median age 34 years, range 25-52). Eleven had a history of thrombosis. Twenty one patients had IgG/M aCL and/or LA, but only 19 fulfilled Sapporo criteria for APS. RESULTS: IgA aCL were found in 12, 6, and 14 patients from the groups with PAPS, unexplained pregnancy morbidity, and SLE, respectively. Most patients had these antibodies together with IgG/IgM aCL. Three patients from the group with unexplained pregnancy morbidity and two with SLE had IgA aCL alone. IgA abeta(2)GPI was present in one patient from each group. All IgA abeta(2)GPI were present together with IgG and/or IgM abeta(2)GPI. CONCLUSIONS: The prevalence of IgA aCL is high in patients with pregnancy morbidity, although IgA aCL are usually present together with IgG and/or IgM aCL. IgA abeta(2)GPI are not useful in identifying additional women with APS and pregnancy morbidity.     

A followup study of antiphospholipid antibodies and associated neuropsychiatric manifestations in 137 children with systemic lupus erythematosus

OBJECTIVE: To determine the prevalence of anticardiolipin antibodies (aCL), anti-beta(2)-glycoprotein I (anti-beta(2)GPI) antibodies, and lupus anticoagulant (LAC) in a large cohort of children with systemic lupus erythematosus (SLE), and to evaluate the associations with neuropsychiatric manifestations. METHODS: A single-center retrospective cohort study with longitudinal followup of antiphospholipid antibodies (aPL) in 137 children with SLE (25 boys and 112 girls, mean age at diagnosis 13.0 years) was performed. Patients were followed up for a mean of 31 months. RESULTS: At the time of diagnosis, 65% of the children were aCL positive, 41% had anti-beta(2)GPI antibodies, and 26% were LAC positive. Analysis of the association between presence of aPL and individual neuropsychiatric manifestations at diagnosis showed a statistically significant association of positive LAC with cerebrovascular disease (5 patients; P = 0.015). A persistently positive aCL was observed in 50%, anti-beta(2)GPI antibodies in 29%, and LAC in 16% of children over time. The prevalence of anti-beta(2)GPI antibodies, but not aCL and LAC, was found to be statistically significantly higher in children with neuropsychiatric disease compared with those without (P = 0.02). Comparison for specific neuropsychiatric manifestations showed a statistically significant association between a persistently positive LAC and chorea (2 patients; P = 0.02). CONCLUSION: The prevalence of anti-beta(2)GPI antibodies was found to be higher in the group of SLE patients with neuropsychiatric disease compared with those without. Our data suggest an association between LAC and cerebrovascular disease at the time of SLE diagnosis and chorea over the disease course, but not between aPL and other neuropsychiatric manifestations.     

Distribution of two common idiotypes of anticardiolipin antibodies in sera of patients with primary antiphospholipid syndrome, systemic lupus erythematosus and monoclonal gammopathies.

The frequency of two common idiotypes of anticardiolipin antibodies (aCL) was determined in sera from three groups of subjects, patients with systemic lupus erythematosus (SLE), with primary antiphospholipid syndrome (PAPS) and with monoclonal gammopathies (MG), as compared to normal population. The idiotype 1.10, which was derived from a patient with active SLE and antiphospholipid syndrome, was found more frequently among patients with PAPS (10.5%, 10.5% and 22.2% in MG, SLE and PAPS, respectively) than the idiotype H3, which was derived from a human hybridoma monoclonal aCL generated from a healthy subject immunized with tetanus and diphtheria. The latter idiotype was detected in 8.7%, 6.5% and 11.7% of patients with MG, SLE and PAPS, respectively. Incidental findings in this study include a high prevalence of aCL among patients with MG (23%) and a high prevalence of anti-dsDNA antibodies, detected only by a sensitive enzyme-linked immunosorbent assay, among patients with PAPS. Our results indicate that idiotypic diversity exists among aCL derived from different sources. Some of these cross-reactive idiotypes may be more pathogenic than others.     

Antiphospholipid antibody tests: spreading the net

OBJECTIVE: To examine the hypothesis that testing for new antiphospholipid antibody specificities may help to identify the antiphospholipid syndrome (APS) in patients with systemic lupus erythematosus (SLE) with thrombosis who are repeatedly negative for anticardiolipin antibodies (aCL) and/or lupus anticoagulant (LA). METHODS: Three groups of patients with SLE were studied: (a) SLE/APS (n = 56): 51 female, mean (SD) age 46 (11) years, fulfilling 1999 Sapporo criteria for the APS; (b) SLE/thrombosis (n = 56): 53 female, age 42.6 (12) years, all with a history of thrombosis and persistently negative for aCL and/or LA; (c) SLE only (n = 56): 53 female, age 40 (11) years, without a history of thrombotic events. aCL and LA were retested in all samples. All patients were tested for anti-beta(2)-glycoprotein I (anti-beta(2)GPI) and antiprothrombin antibodies (aPT) by coating prothrombin on irradiated plates or using phosphatidylserine-prothrombin complex as the antigen (aPS-PT). RESULTS: Anti-beta(2)GPI were only present in patients from the SLE/APS group, all of whom were also positive for aCL. aPT and aPS-PT were also more commonly found in SLE/APS than in SLE/thrombosis or SLE only groups (54% v 5%, p<0.0001 or v 16%, p<0.0001 for aPT and 63% v 2%, p<0.0001 or v 11%, p<0.0001 for aPS-PT, respectively). No differences were found between SLE/thrombosis and SLE only groups (p = 1.5 for beta(2)GPI, p = 0.1 for aPT, and p = 0.1 for aPS-PT). CONCLUSION: Testing for aPT in patients with SLE with thrombosis, but persistently negative for aCL and LA, may be helpful in some selected cases. Anti-beta(2)GPI are not present in patients who are negative for aCL.     

HLA-DPB1 alleles association of anticardiolipin and anti-beta2GPI antibodies in a large series of European patients with systemic lupus erythematosus

Our objective was to determine the HLA-DPB1 allele associations of anticardiolipin (aCL) and anti-beta2GPI (a(beta)2GPI) antibodies, and of clinical manifestations of the antiphospholipid syndrome (APS), in systemic lupus erythematosus (SLE). We studied 577 European patients with SLE. aCL and a(beta)2GPI antibodies were measured by ELISA. Molecular typing of HLA-DPB1 locus was performed by polymerase chain reaction-sequence specific oligonucleotide probe (PCR-SSOP) method. aCL showed positive association with -DPB1*1501 (P = 0.005, OR = 7.4), and -DPB1*2301 (P = 0.009, OR = 3.3). a(beta)2GPI showed positive association with -DPB1*0301 (P = 0.01, OR = 1.9), and -DPB1*1901 (P = 0.004, OR = 8.1). In addition, livedo reticularis was associated with -DPB1*1401, and Raynaud's phenomenon with -DPB1*2001. In conclusion, HLA-DPB1 locus may contribute to the genetic predisposition to develop antiphospholipid antibodies and clinical manifestations of the APS in patients with SLE.     

Raynaud's phenomenon and antiphospholipid antibodies in systemic lupus erythematosus: is there an association?

OBJECTIVE: To evaluate the association of IgG and IgM antibodies directed against different negatively charged phospholipids (that is, anticardiolipin (aCL), antiphosphatidylinositol, antiphosphatidylserine, and antiphosphatidic acid) and anti-beta(2)-glycoprotein I (abeta(2)GPI), with Raynaud's phenomenon in patients with systemic lupus erythematosus (SLE). METHODS: Ninety three patients with SLE (81 female), 40 with and 53 without Raynaud's phenomenon, were included in the study. IgG and IgM antiphospholipid antibodies and abeta(2)GPI were determined by enzyme linked immunosorbent assay (ELISA). RESULTS: Fifty patients (54%) were positive for IgG and/or IgM antibodies to one or more phospholipid antigens or to beta(2)GPI. The prevalence of all autoantibodies evaluated, either IgG or IgM, was higher in patients without than in those with Raynaud's phenomenon. A negative association was found between IgG aCL and Raynaud's phenomenon (p=0.038), whereas autoantibodies other than aCL were not significantly associated with Raynaud's phenomenon. CONCLUSION: Our results demonstrate no positive association between antiphospholipid antibodies and Raynaud's phenomenon in SLE and indicate that measurement of anti-negatively charged phospholipid antibodies other than aCL is not useful as a serological marker predictive for Raynaud's phenomenon.     

IgG anti-beta2-glycoprotein I antibodies in adult patients with systemic lupus erythematosus: prevalence and diagnostic value for the antiphospholipid syndrome

OBJECTIVE: To investigate the prevalence of serum anti-beta2-glycoprotein I (anti-beta2-GPI) antibodies and other antiphospholipid antibodies (aPL) in patients with systemic lupus erythematosus (SLE). To study their diagnostic value for the antiphospholipid syndrome (APS). METHODS: Anti-beta2-GPI and IgG anticardiolipin (aCL) were determined in sera from 102 consecutive patients with SLE using ELISA. Serum and plasma tests were also done for lupus anticoagulant (LAC), syphilis, and antibodies to dsDNA. Clinical and laboratory features of APS were observed. RESULTS: Prevalences were 23.5% for aCL and 18.6% for anti-beta2-GPI. Correlations between the presence of aCL and anti-beta2-GPI and between their titers were statistically significant (p<0.0001). No associations were found between anti-beta2-GPI and disease activity criteria (SLEDAI, ECLAM, dsDNA). Anti-beta2-GPI were significantly associated with LAC (p = 0.005), APS (p = 0.005), and a high aCL titer (aCL > 5 SD; p< or =0.001). LAC was the best diagnostic criterion for APS. CONCLUSION: These data suggest that determination of anti-beta2-GPI in addition to aCL and LAC is unlikely to improve the diagnosis of APS in patients with SLE.     

Anticardiolipin and anti-beta2glycoprotein-I antibodies in patients with systemic lupus erythematosus: comparison between Colombians and Spaniards

We studied the prevalence, isotype distribution, and clinical significance of anticardiolipin (aCL) and anti-beta2glycoprotein I (anti-beta2GPI) antibodies in two populations of patients with systemic lupus erythematosus (SLE), 160 Colombians and 160 Spaniards. All sera were tested in our laboratory by enzyme-linked immunosorbent assay (ELISA) for IgG, IgM, and IgA aCL, as well as IgG and IgM anti-beta2GPI. Positive results for at least 1 of the 3 aCL isotypes were found in 40 Colombians (25%) and 55 Spaniards (34%). IgG aCL was the predominant isotype in both populations. Positive results for at least 1 of the anti-beta2GPI isotypes were found in 34 Colombians (21%) and 29 Spaniards (18%). IgG anti-beta2GPI was the dominant isotype in Colombians, while IgM was predominant in Spaniards. Positivity for anti-beta2GPI in aCL-positive patients was present in 77% in the Colombian group and 50% in the Spaniard group. Among Colombians, IgG aCL and anti-beta2GPI correlated with thrombosis, fetal loss, and thrombocytopenia. Among Spaniards, IgG aCL and IgG anti-beta2GPI correlated with thrombosis, fetal loss, and livedo reticularis. For detecting thrombosis and fetal loss, aCL ELISA was more sensitive than anti-beta2GPI in Spaniards, and anti-beta2GPI ELISA was more specific than aCL in both populations.     

Anticardiolipin and anti-beta2GPI antibodies in a large series of European patients with systemic lupus erythematosus. Prevalence and clinical associations. European Concerted Action on the Immunogenetics of SLE

OBJECTIVE: To test the prevalences and the clinical associations of anticardiolipin (aCL) and anti-beta2GPI (abeta2GPI) antibodies in a large series of European patients with systemic lupus erythematosus (SLE). METHODS: 574 SLE patients from 7 European countries were tested for aCL and abeta2GPI by ELISA methods. RESULTS: aCL of IgG, IgM, and IgA isotypes were detected in 22.8%, 14%, and 13.9% of the patients, respectively. IgG and IgM abeta2GPI were detected in 20% of the patients. The presence of aCL was highly associated with the presence of abeta2GPI. Medium-high titer IgG aCL and abeta2GPI were associated with thrombosis, with similar sensitivity, specificity, and positive predictive value. When present at medium-high titer, IgG aCL were associated with thrombocytopenia, IgM aCL with hemolytic anemia, and cerebrovascular accidents. IgA aCL with livedo reticularis and Raynaud's phenomenon. CONCLUSIONS: aCL, when present at medium-high titer, are as important as abeta2GPI, as a risk factor for thrombosis. Medium-high titer aCL, but not abeta2GPI, are associated with other clinical features of the antiphospholipid syndrome.     

Clinical utility of laboratory tests used to identify antiphospholipid antibodies and to diagnose the antiphospholipid syndrome

The antiphospholipid syndrome (APS) is defined by thrombotic and/or obstetric events together with the presence of antiphospholipid antibodies in plasma of patients. The original laboratory criteria of APS included lupus anticoagulants (LA) and/or IgG/IgM anticardiolipin antibodies (aCL). They were recently updated with the addition of IgG/IgM anti-beta2 glycoprotein I antibodies (anti-beta2GPI), a better definition of "medium to high antibody titer," and the extension to 12 weeks of the "persistence in time." The revised criteria represent an improvement; however, the potential overdiagnosis of APS remains possible, thus putting patients at risk of overtreatment. To reduce this possibility, proposals have been made to implement strict guidelines for the performance of the LA assay, to exclude aCL measurements in their current application from the criteria, and to limit the measurement of anti-beta2GPI to the G isotype. This should also help in simplifying the laboratory workup of patients being investigated for APS.     

Antiphospholipid syndrome in autoimmune diseases

Classification criteria for antiphospholipid syndrome were first proposed in 1987, revised in 1999 (Sapporo criteria) and up-dated in 2006. The aim of the study was to analyze associations between clinical and laboratory symptoms of antiphospholipid syndrome in the group of patients with autoimmune diseases, based on recently up-dated classification criteria. 336 patients were enrolled into the study, with the majority (n=235) suffering from SLE. Laboratory determinations included: lupus anticoagulant (LA), anticardiolipin (aCL) and anti-beta2-glycoprotein I (abeta2GPI) (both of IgG and IgM class). Clinical and laboratory symptoms of antiphospholipid syndrome were quite common among patients studied. There was a significant association between laboratory and clinical features of antiphospholipid syndrome, according to recently modified classification criteria.     

血清C1q抗体水平与系统性红斑狼疮活动性和狼疮肾炎的关系

目的分析探讨血清C1q抗体水平与系统性红斑狼疮（SLE）活动性以及狼疮肾炎之间的关系。方法采用ELISA方法检测92例SLE患者C1q抗体水平。并与其他SLE活动性指标进行相关分析。结果SLE患者C1q抗体阳性率为67.4%。活动性狼疮组的C1q抗体阳性率及C1q抗体水平显著高于非活动性狼疮组（P〈0.001）。活动性狼疮肾炎组C1q抗体阳性率（P〈0.05）和C1q抗体水平（P〈0.01）显著高于非活动性狼疮肾炎组。联合抗dsDNA抗体检测,没有1例活动性狼疮肾炎患者的C1q抗体和抗dsDNA抗体同时阴性。结论血清C1q抗体与狼疮活动以及活动性狼疮肾炎关系密切,C1q抗体的检测有助于活动性狼疮的诊断,联合抗dsDNA抗体的检测是活动性狼疮肾炎的特异性检测指标。     

Correlation between beta2-glycoprotein I valine/leucine247 polymorphism and anti-beta2-glycoprotein I antibodies in patients with primary antiphospholipid syndrome.

OBJECTIVES: Beta2-Glycoprotein I (beta2GPI) exon 7 polymorphism leads to a valine leucine amino acid exchange at position 247 in domain 5 of beta2GPI, between the phospholipid binding site and the cryptic site of the epitopes for anti-beta2GPI antibodies. Therefore, position 247 polymorphism may affect the conformational change of beta2GPI and the exposure of the epitopes for anticardiolipin antibodies (aCL) (= anti-beta2GPI antibodies). In this study we analysed the genetic polymorphism of beta2GPI in a British cohort of well-defined antiphospholipid syndrome (APS) patients. METHODS: This study comprised 88 Caucasoid patients with APS [57 with primary APS and 31 with APS secondary to systemic lupus erythematosus (SLE)]. Polymorphism assignment was determined by polymerase chain reaction followed by allele-specific restriction enzyme digestion (PCR-RFLP). The presence of anti-beta2GPI antibodies was detected by ELISA utilizing irradiated ELISA plates. RESULTS AND CONCLUSIONS: Anti-beta2GPI antibodies were present in 28 of 57 primary APS patients (49%) and in 19 of 31 secondary APS patients (61%). The allele containing valine247 was significantly more frequent in primary APS patients with anti-beta2GPI antibodies than in controls (OR = 2.51, 95%, CI 1.03-6.13, P = 0.0396) or in primary APS patients without anti-beta2GPI antibodies (OR = 2.92, 95% CI 1.16-7.39, P = 0.0204). This tendency was not found in the secondary APS group. In conclusion, the beta2GPI polymorphism, valine/leucine247, is correlated with anti-beta2GPI antibody production in patients with primary APS, and valine247 may be important in the formation of beta2GPI antigenicity.     

IgA anticardiolipin and anti-beta2-glycoprotein I are the most prevalent isotypes in African American patients with systemic lupus erythematosus.

BACKGROUND: Ethnicity plays a role in the prevalence, isotype distribution, and clinical significance of anticardiolipin (aCL) and anti-beta2-glycoprotein I (anti-beta2-GPI) antibodies in patients with systemic lupus erythematosus (SLE). Few studies have been done in the African American population. METHODS: Serum samples from 100 African American patients with SLE were tested for IgG, IgM, and IgA aCL and anti-beta2-GPI antibodies by enzyme-linked immunosorbent assay (ELISA). Computerized clinical data on these patients were reviewed with a specific focus on clinical manifestations of antiphospholipid syndrome (APS). RESULTS: Positivity for at least one isotype of aCL antibodies was found in 33% of the patients, whereas 28% were positive for at least one isotype of anti-beta2-GPI antibodies. IgA was the most prevalent isotype for both antibodies; 24% of the patients in the aCL ELISA and 19% in the anti-beta2-GPI ELISA were positive for IgA. Positivity for both aCL and anti-beta2-GPI in the same patient was seen more frequently with the IgA isotype. Fewer than half of the patients positive for aCL antibodies had medium-to-high levels of antibodies. A few patients had presented thrombotic manifestations, and these patients were positive for aCL (P = 0.01) and anti-beta2-GPI antibodies (P = 0.02). No other manifestations of APS could be significantly correlated with the presence of these antibodies. CONCLUSIONS: Our results show that IgA is the most prevalent isotype among the African American patients with SLE studied. The predominance of the IgA isotype and the low prevalence of medium-to-high levels of aCL antibodies may account for the low frequency of clinical manifestations of APS in these patients.     

The persistence of anticardiolipin antibodies is associated with an increased risk of the presence of lupus anticoagulant and anti-beta2-glycoprotein I antibodies

OBJECTIVE: We studied antiphospholipid antibodies (aPL) in blood samples from a cohort of individuals followed for thrombosis to determine whether the persistent presence of anticardiolipin antibodies (aCL) is associated with a greater likelihood of having lupus anticoagulant and/or anti-beta2-glycoprotein I antibodies (LA/abeta2GPI). METHODS: Blood samples from 353 individuals who had been tested for aCL on at least two occasions were tested for abeta2GPI and LA. Two groups were defined: aCL-persistent, who tested aCL-positive on at least two occasions, and aCL non-persistent, who tested aCL-positive on fewer than two occasions. Multivariate logistic regressions were performed using LA/abeta2GPI, LA and abeta2GPI as outcome variables and the percentage of aCL-positive tests as the predictor variable, adjusted for age, gender, family history of cardiovascular disease (CVD), systemic lupus erythematosus (SLE), smoking and number of venous (VT) and arterial thromboses (AT). RESULTS: Sixty-eight (19%) individuals were aCL persistent and 285 (81%) were aCL non-persistent. LA/abeta2GPI was found in 36 (53%) of the aCL persistent group and 38 (13%) of the aCL non-persistent group. The two groups were similar for age, gender and smoking. Family history of CVD, SLE, VT and AT were more frequent in the aCL persistent group. Multivariate analyses revealed that odds ratios for LA/abeta2GPI, LA and abeta2GPI were 1.34 [95% confidence interval (CI) = 1.22-1.47], 1.36 (95% CI = 1.24-1.50) and 1.47 (95% CI = 1.31-1.65) respectively for each 10% increase in aCL-positive tests vs 0% positive tests. CONCLUSION: Persistence of aCL positivity is associated with an increased risk of LA/abeta2GPI.     

Antiphospholipid (Hughes') syndrome in African-Americans: IgA aCL and abeta2 glycoprotein-I is the most frequent isotype.

Antiphospholipid (Hughes') syndrome (APS) has not been reported in African-Americans (A-A) as frequently as in other ethnic groups. We describe eight A-A female patients with APS, including two cases of primary APS (PAPS), four with APS secondary to systemic lupus erythematosus (SLE), one with Sj?gren's syndrome, and one with overlap connective tissue disease (CTD). Their mean age was 34 y (range 24-47 y). Patients were followed for a mean of 6 y (range 0.3-11 y). During follow up, both anticardiolipin (aCL) and anti-beta2glycoprotein-I (abeta2GPI) antibodies were measured in stored sera by enzyme-linked immunosorbent assay (ELISA). IgA was the most frequent isotype of aCL and abeta2GPI, and co-occurred with the IgM isotype in three of four patients with neurologic manifestations.     

Longitudinal study of antinuclear and anticardiolipin antibodies in pregnant women with systemic lupus erythematosus and antiphospholipid syndrome

The objective of this study was to perform a longitudinal follow-up of antinuclear antibodies (ANAs) and anticardiolipin antibodies titers (aCL) throughout pregnancy in a group of patients with systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) patients during their therapy for the prevention of fetal loss and to examine their relationship with pregnancy outcome. Thirty patients and 15 controls were followed in the study. Fifteen patients had SLE (group I) and 15 had APS (group II, of which seven patients had primary APS and eight had APS secondary to SLE). All patients were receiving therapy for the prevention of fetal loss with prednisone and aspirin as part of an ongoing clinical trial in lupus pregnancy. If there was a history of previous thrombosis, heparin was added. Blood samples were taken at the 1st, 2nd, and 3rd trimesters (T) of pregnancy in order to assess the presence of IgG and IgM aCL antibodies (ELISA), anti-dsDNA ( C. luciliae) ANAs (HEp-2 cells), and immunospecific antibodies (antiextractable nuclear antigens). We collected 90 samples from patients and 45 samples from healthy controls. Group I (SLE) ANAs were positive in 100% during the 1st T, 67% in the 2nd T, and 67% in the 3rd T, with various immunofluorescence patterns. In five patients, aCL antibodies were detected without a history of APS (one in 1st T, three in 2nd T, and one in 3rd T). Fetal loss was observed in two patients, in one of whom it was associated with nephritis, high titers of ANAs, and anti-dsDNA. Another patient had pulmonary hemorrhage with anti-dsDNA and aCL. In group II, all but one patient with primary APS were negative to ANAs. In secondary APS, by contrast, 6/8 patients (75%) had positive ANAs at least during the 1st T. All seven patients with primary APS and 6/8 with secondary APS had aCL during pregnancy. In 9/15 (60%) patients from the APS group with a history of previous fetal loss, aCL became negative during pregnancy and they had live births. The disappearance of aCL was associated with improved fetal survival (relative risk, or RR, 0.67). ANAs in the control group were positive in 7% at low titers, and all of them were negative for aCL. Despite treatment, ANAs are prevalent during pregnancy in SLE patients and APS secondary to SLE. During pregnancy in SLE, aCL titers may appear. Decreasing titers and/or disappearance of aCL correlated with improved fetal prognosis in a subset of patients with APS.     

Antibodies to high-density lipoprotein and beta2-glycoprotein I are inversely correlated with paraoxonase activity in systemic lupus erythematosus and primary antiphospholipid syndrome

OBJECTIVE: To determine the prevalence of anti-high-density lipoprotein (anti-HDL) antibodies and to establish a possible relationship between anti-HDL, anticardiolipin antibodies (aCL), anti-beta(2)-glycoprotein I (anti-beta(2)GPI), and paraoxonase (PON) activity in patients with systemic lupus erythematosus (SLE) and primary antiphospholipid syndrome (APS). METHODS: Thirty-two patients with SLE and 36 with primary APS were enrolled in a cross-sectional study. Twenty age- and sex-matched healthy subjects were used as controls. Serum levels of IgG and IgM aCL, anti-beta(2)GPI, and antiprothrombin antibodies and IgG anti-HDL were measured by enzyme-linked immunosorbent assay. Total cholesterol, HDL cholesterol, HDL(2), and HDL(3) were determined by standard enzymatic techniques. PON activity was assessed by quantification of nitrophenol formation, and total antioxidant capacity (TAC) by chemiluminescence. RESULTS: Levels of total HDL, HDL(2), and HDL(3) were reduced in patients with SLE compared with controls (mean +/- SD 0.51 +/- 0.3, 0.37 +/- 0.3, and 0.14 +/- 0.1 mmoles/liter, respectively, versus 1.42 +/- 0.9, 1.01 +/- 0.7, and 0.40 +/- 0.2). Patients with SLE and primary APS had higher titers of anti-HDL antibodies and lower PON activity than controls. In the SLE population, PON activity was inversely correlated with IgG anti-HDL titers (r = -0.48, P = 0.005) whereas in the primary APS population, IgG anti-beta(2)GPI was the only independent predictor of PON activity (r = -0.483, P = 0.003). In the SLE group, anti-HDL was inversely correlated with TAC (r = -0.40, P < 0.02), and PON activity was positively correlated with TAC (r = 0.43, P < 0.02). CONCLUSION: IgG anti-HDL and IgG anti-beta(2)GPI antibodies are associated with reduced PON activity in patients with SLE and primary APS. Since the physiologic role of PON is to prevent low-density lipoprotein oxidation with its attendant atherogenic effects, the reported interactions may be relevant to the development of atherosclerosis in SLE and primary APS.     

Isotypes of anti-beta2-glycoprotein I antibodies: association with thrombosis in patients with systemic lupus erythematosus

OBJECTIVE: To evaluate the association between isotypes of anti-beta2-glycoprotein I antibodies (anti-beta2-GPI) and thrombosis and to identify antiphospholipid antibodies (aPL) that are most associated with thrombosis in patients with systemic lupus erythematosus (SLE). METHODS: IgG anticardiolipin antibody (aCL) and isotypes of anti-beta2-GPI were measured by ELISA, and clinical evidence of thrombosis was analyzed in 270 patients with SLE. RESULTS: IgG, IgM, and IgA anti-beta2-GPI were positive in 38.1, 13.7, and 34.8% of patients, respectively. Patients with a history of thrombosis were significantly more likely to have lupus anticoagulant (LAC), IgG aCL, and the 3 anti-beta2-GPI isotypes. Arterial thrombosis was associated with the presence of IgG aCL and the 3 anti-beta2-GPI isotypes, whereas venous thrombosis was associated with LAC, IgG aCL, and IgA anti-beta2-GPI. In stepwise multivariate logistic regression analysis, the variable that was associated with thrombosis was IgA anti-beta2-GPI. The occurrence of arterial thrombosis was associated with IgG aCL and that of venous thrombosis was related to IgA anti-beta2-GPI in stepwise multivariate analysis. The IgG, IgM, and IgA anti-beta2-GPI titers were closely correlated with IgG aCL titers. The IgA anti-beta2-GPI titers were also significantly correlated with those of IgG and IgM anti-beta2-GPI. CONCLUSION: The results suggest that anti-beta2-GPI isotypes are related to the occurrence of thrombosis, and measurements of IgA anti-beta2-GPI may be useful for predicting thrombotic episodes in patients with SLE.     

Specificity and sensitivity of anti-beta2-glycoprotein I as compared with anticardiolipin antibody and lupus anticoagulant in Thai systemic lupus erythematosus patients with clinical features of antiphospholipid syndrome

Antibodies to beta(2)-glycoprotein I (anti-beta(2)-GPI) have been reported to have stronger association with clinical antiphospholipid syndrome (APS) than anticardiolipin antibodies (aCL) and lupus anticoagulant (LAC). We investigated the sensitivity and specificity of ELISA for anti-beta(2)-GPI in Thai systemic lupus erythematosus (SLE) patients with clinical features of APS and compared the results with IgG/IgM aCL and LAC to find the test with the best association. The hospital records of 151 Thai SLE patients whose sera had been sent for either IgG/IgM anticardiolipin antibodies or lupus anticoagulant testing were reviewed. Sera of patients either without complete clinical records or those with APS-related manifestations other than vascular thrombosis and pregnancy morbidity (according to the international consensus statement on preliminary classification criteria for definite APS) were excluded. For the remaining subjects (112 patients), their sera were tested for anti-beta(2)-GPI antibody, IgG and IgM anticardiolipin, and lupus anticoagulant. The sensitivity and specificity of each method were compared by using the chi-square test. Among the 112 (74.2%) SLE patients in the study, 35 (31.3%) presented with preliminary clinical criteria for APS (i.e., vascular thrombosis and pregnancy morbidity) whereas 77 (68.7%) did not. The sensitivity and specificity of anti-beta(2)-GPI determination were 57.1 and 79.2%, respectively, whereas those of IgG aCL were 25.7 and 94.8%, of IgM aCL were 5.7 and 98.7%, and of LAC were 44.8 and 77.3%, respectively. The accuracy of the four tests showed similar association with clinical APS (accuracy of test = 72.3, 73.2, 69.6, and 68.3%, respectively). Concerning the sensitivity, specificity, and difficulty of the methods, the combination of anti-beta(2)-GPI and IgG aCL tests was the best for the diagnosis of APS in Thai SLE patients.