Positive aCL Research Articles

Anticardiolipin, other antiphospholipid antibody tests and diagnosis of the antiphospholipid syndrome

The frequent occurrence of false positive results in the anticardiolipin (aCL) enzyme linked immunosorbent assay (ELISA) hampers its application in identifying the antiphospholipid syndrome (APS), a condition characterized by a myriad of clinical presentations. This study highlights some of the pitfalls in the use of assays for antiphospholipid (aPL) antibody in clinical practice. The aCL ELISA, commercially prepared anti-beta2-gylcoprotein 1 (beta2-GP1) and antiphospholipid (APhL) assays were evaluated in the diagnosis of antiphospholipid syndrome (APS) in 94 pregnant women who had spontaneous abortion and a group of 177 healthy blood donors. Serological tests were used to rule out syphilis as the cause of false positive results in the aCL ELISA. The prevalences of positive aCL ELISA results (29/94, 31% v 26/177, 14%; p = 0.001) and aCL antibodies of the IgM isotype (19/94, 20% v 6/177, 3%; $p = 0.001$) were significantly higher in aborters compared to healthy subjects. The majority of the sera which were positive in the aCL ELISA were shown to be false positives as 93% (27/29) of aCL positive aborters and 67% (8/24) of aCL positive healthy subjects were negative in the anti-beta2-GP1 assay. Similarly, the sensitivity of the APhL ELISA was low and only 1% (1/94) of the sera of aborters and 6% (11/177) of healthy subjects were positive in this assay. The frequent occurrence of anticardiolipin antibodies of the authentic non-autoimmune variety and the low sensitivity of the other more specific aPL assays make the positive aCL ELISA difficult to interpret. We recommend that the diagnosis APS be made with strict adherence to the preliminary criteria for classification of APS.

Left-sided heart valve abnormalities and risk of ischemic cerebrovascular accidents in patients with systemic lupus erythematosus.

The aim of the study was to assess the relationship between ischemic cerebrovascular accidents (ICVAs), that is, transient ischemic attack (TIA) or stroke, and left-sided heart valve abnormalities (LHVAs) in patients with systemic lupus erythematosus (SLE). In total, 71 consecutive SLE patients were studied. At baseline, history, clinical and laboratory evaluations, as well as trans-thoracic echocardiography (TTE) were performed. From the original population, so patients were followed up for a mean time of 5.80 +/- 1.53 years. After a mean period of 5.39 +/- 1.42 years; 40 patients underwent a repeat TTE. Previous ICVA history was present at baseline in 16 patients (22.5%). Of these, 13 (81.2%) had evidence of LHVAs on TTE. Previous ICVAs were significantly associated to diagnosis of secondary anti-phospholipid syndrome (SAPS), positivity for anti-cardiolipin antibodies (aCl), and LHVAs. Multivariate analysis confirmed the correlation between previous ICVAs and LHVAs. LHVAs were not more commonly observed in patients with SAPS compared to patients without SAPS. At the end of follow-up, irrespective of any differences in antithrombotic treatment, ICVAs had occurred in 13 patients. During follow-up, ICVAs had recurred in seven patients, while a first event TIA occurred in one patient. Multivariate analysis confirmed the relationship between ICVAs and LHVAs, and a trend towards a positive correlation of the former with SAPS. This study demonstrates that LHVAs represent a compelling risk factor for the development of ICVAs in SLE patients. Conversely, SAPS and aCl positivity, although associated with ICVAs, did not clearly correlate with LHVAs in our study. These results provide insight on the pathogenesis of ICVAs and may give clues on the potential efficacy of preventive/therapeutic strategies in different SLE subpopulations.

Frequency of anticardiolipin, antinuclear and anti β2GP1 antibodies is not increased in unselected epileptic patients: a case-control study

In order to determine whether auto antibodies were restricted to some subtypes of epilepsy, we included 81 unselected epileptic patients and 81 controls, studied clinical data, EEG, neuroimaging, measured antinuclear (ANA), anticardiolipin (aCL) and β2GP1 antibodies. Results: Epilepsy was active in 74 patients, generalised in 78 and partial in 9. Auto antibodies were positive at the same frequency and the same level among patients and controls (ANA+ 17% vs. 11%; aCL+ 4% vs. 7%; β2GP1 antibodies+ 5% vs. 6%). There was no increased frequency of auto antibodies among subgroups of epileptic patients except ANA which were more frequent when patients had more than 10 seizures per year. Conclusions: Positivity of ANA, aCL and β2GP1 antibodies is not increased in all types of epilepsy and further studies are needed to determine exactly which kind of seizure is immune-mediated.

Symptomatic thrombotic events among Egyptian patients with systemic lupus erythematosus: special consideration for renal vein thrombosis.

To evaluate the prevalence of symptomatic thrombotic events among Egyptian patients with systemic lupus erythematosus (SLE), and to evaluate the frequency and the risk factors associated with renal vein thrombosis in those patients. Fifty-four patients with SLE, 51 (94.4%) females, were involved in this study. All of them were submitted for abdominal sonography, chest X-ray, echocardiography, and Doppler of renal, abdominal and lower limb veins, with examination of data on clinical and laboratory profile. Abdominal CT, brain MRI, MRI both hips, CT chest and pulmonary scintigraphy were used when needed. Sixteen patients (29.6%) were diagnosed with symptomatic thrombotic events. Eight patients had more than one type of thrombosis. Two patients (3.7%) were diagnosed by Doppler as having renal vein thrombosis (RVT). This was confirmed by abdominal CT. One of them presented with nephrotic syndrome, graded by renal biopsy as World Health Organization (WHO) class V, and had positive anticardiolipin antibodies (ACL). The other patient had RVT and inferior vena cava (IVC) thrombosis, nephrotic syndrome, positive ACL, and died before renal biopsy was performed. Both of them were without history of peripheral thrombotic events. One patient was diagnosed with IVC thrombosis, lupus nephritis grade II, positive ACL, and diagnosed by abdominal CT. One patient was diagnosed with portal vein thrombosis and had positive ACL. One patient with retinal vessel thrombosis and positive ACL. Four patients had deep vein thrombosis (DVT). Recurrent miscarriages were reported in 4 patients (7.4%), skin ulcerations in 3 (5.6%), avascular necrosis of the hips in 4 (7.4%), stroke in 1 (1.9%), and pulmonary hypertension in 2 patients (3.7%). Sixteen SLE patients (29.6%) were diagnosed with symptomatic thrombotic events. RVT was detected in 2 patients representing 3.7% of all patients, and 12.5% of patients with thrombosis. Both patients with RVT presented with nephrotic syndrome.

Analysis of risk factors and comorbid diseases in the development of thrombosis in patients with anticardiolipin antibodies.

Our objective was to identify the role of various disease states and additional risk factors in the development of thrombosis in patients with anticardiolipin antibodies (aCL). We undertook a retrospective chart review of patients with aCL (IgG or IgM titres > 20 GPL or 20 MPL by ELISA). Patients with a thrombotic event were compared to patients without thrombosis for potential risk factors: age, gender, ethnicity, hypertension (HTN), diabetes (DM), hyperlipidaemia, tobacco use and sequential aCL determinations. The role of systemic lupus erythematosus (SLE), human immunodeficiency virus (HIV), hepatitis C and renal disease was also analysed. Statistical analysis was performed using the t-test, the chi(2) test and multivariate analysis. Of the 107 patients who had moderately positive aCL (IgM and/or IgG), 53 had a thrombotic event. The patients with thrombosis were significantly older than patients without thrombosis (mean age 46.6 vs. 38.75 years, respectively, P=0.014). No significant differences in gender, race, HTN, DM, hyperlipidaemia, tobacco use or concomitant diseases were identified in the two groups. Thrombosis was more frequent in patients who were seropositive for both IgG and IgM ( P=0.027). Thrombosis was observed in equal frequencies in patients with aCL on both determinations and in patients with aCL on only one of the two determinations. In patients with aCL on two determinations a high-titre IgG aCL was associated with thrombosis. Patients with renal disease and aCL on only one of the two determinations had fewer thrombotic events ( P=0.0046). Mean aCL IgM titres were higher in thrombosis groups containing venous thromboses than in the thrombosis group with arterial thrombosis only. We concluded that risk factors for thrombosis with a single aCL determination include older age and both IgM and IgG aCL. With persistent aCL, high-titre IgG aCL was associated with thrombosis.

Does the anti-β 2-glycoprotein I antibody provide additional information in patients with thrombosis?

Objective: To investigate whether the anti-β 2-glycoprotein I (anti-β 2GPI) antibody may provide additional information in patients with thrombosis in conjunction with the lupus anticoagulant (LAC) or anticardiolipin (aCL) antibody. Methods: We selected 235 patients whose plasma were tested for the presence of all three antiphospholipid (aPL) antibodies (LAC, aCL, and anti-β 2GPI) and were positive for at least one aPL antibody from January 2000 to December 2001. The LAC test was performed using dilute activated thromboplastin time reagent (dAPTT) and dilute Russell viper venom time reagent (dRVVT). ACL (IgG/IgM) and anti-β 2GPI (IgG/IgM) were detected by enzyme-linked immunosorbent assay (ELISA). Clinical data were collected and analysed in all patients with aPL antibody. Results: Of the 235 patients with aPL, thrombosis was detected in 76 patients (28.0%). Of the 76 patients with thrombosis, 29 were positive for LAC, 9 for aCL, 7 for anti-β 2GPI, 3 for LAC+aCL, 9 for aCL+anti-β 2GPI, 11 for LAC+anti-β 2GPI, and 8 for LAC+aCL+anti-β 2GPI. The rate of thrombosis was significantly different ( p=0.01) among single positive patients (45/163, 27.6%), double positive patients (23/60, 38.3%), and triple positive patients (8/12, 66.7%). In single positive patients, the rate of thrombosis was highest in LAC positive patients (29/85, 34.1%). In double positive patients, the LAC+anti-β 2GPI positive group (11/24, 45.8%) and aCL+anti-β 2GPI positive group (9/22, 40.9%) had higher rates of thrombosis than the LAC+aCL positive group (3/14, 21.4%). Conclusion: Single positivity for anti-β 2GPI explained 9.2% of thrombotic events in the absence of LAC or aCL. Double or triple positivity for aPLs were associated with a higher rate of thrombosis than single positivity for aPL. Our results suggest that anti-β 2GPI provides additional information in patients with thrombosis in conjunction with LAC or aCL.

Personification of Death, as Seen in Adjective Check List Descriptions, among Funeral Service and University Students

One hundred twenty-nine undergraduate psychology students at a large urban university and 55 students at a college of funeral service completed the Death Anxiety Questionnaire (Conte, Weiner,&Plutchik, 1982), the Revised Death Anxiety Scale (Thorson&Powell, 1994), a nine question measure of belief in an afterlife (Daws, 1980), and used the 300-item Adjective Check List (ACL; Gough&Heilbrun, 1980) to describe what death might be like if personified as a human character in a play. Three Affective Meaning scores, five Transactional Analysis ego state scores, five Five Factor Model scores, and a Sex-Stereotype Index score were calculated based on ACL descriptions of the character of death. Lower death anxiety was associated with more positive ACL descriptions of death in both samples; however, belief in an afterlife was associated with differences in death personification only among university students. Men described death as higher on the Adult ego state than did women. In addition African Americans described death as a more positive character than did European Americans. Similarly, funeral service students described death as feminine, favorable, strong, but not active, more like a Nurturing Parent, and high on Extroversion, Agreeableness, and Emotional Stability; whereas, university students described death as masculine, neutral on Favorability, more like a Critical Parent, and low on Agreeableness and Emotional Stability.

The 27th International Stroke Conference San Antonio, Texas, February 7-9, 2002.

The 27th International Stroke Conference San Antonio, Texas, February 7-9, 2002.

Anticardiolipin antibody positivity in diabetic patients with and without diabetic foot

Anticardiolipin (aCL) antibodies may play a role in the enhancement of platelet aggregation and/or progression of the macrovascular diabetic complications. Also, aCL antibodies may cause or promote ischemia and thrombosis. Therefore, we aimed to investigate IgG aCL and IgM aCL antibodies positivity in type 2 diabetic patients with and without ischemic diabetic foot. In this case-control study, we examined 40 diabetic patients without diabetic foot problem and 35 diabetic patients with ischemic diabetic foot. Forty diabetic patients (19 females, 21 males) without diabetic foot served as Group 1 and 35 diabetic patients (17 females, 18 males) who had ischemic diabetic foot served as Group 2. In the control group, 35 nondiabetic healthy subjects (18 females, 17 males) were included in Group 3. The groups were similar in age and sex, which is not statistically significant ( P>.05). There was no difference in the IgG aCL antibodies positivity between Groups 1 and 3 ( P>.05). However, IgG aCL antibodies positivity in Group 2 was significantly higher than those of the other groups ( P<.05). IgG aCL antibodies were found positive in 10% (4/40) of Group 1, 34.3% (12/35) of Group 2 and 8.6% (3/35) of Group 3. When Groups 1 and 2 were compared, the odds ratio adjusted for age, gender, hypertension, coronary artery disease history, cigarette smoking, duration of diabetes mellitus, cholesterol, and haemoglobin A 1C (HbA1c) was 6.8 [95% confidence interval (CI), 1.41–32.66; P=.016] for aCL positivity. In conclusion, although available evidence does not prove a causal association between positivity of aCL and diabetic foot, we believe that a causal association is supported by the data obtained from this study.

Prevalence and clinical significance of anticardiolipin and anti-beta2-glycoprotein-I antibodies in patients with non-Hodgkin's lymphoma.

The association of antiphospholipid antibodies (APA) has been reported in several cases of patients with non-Hodgkin's lymphoma (NHL) with or without thromboembolic complications. The purpose of this study was to analyse systematically the prevalence of APA and its clinical significance in lymphoma patients. Sera of 90 consecutive unselected patients with NHL were tested for the presence of anticardiolipin (aCL) antibodies and anti-beta2-glycoprotein-I (anti-beta2-GPI) antibodies. The patients were followed up over a median period of 14 months to note the occurrence of thromboembolism. We found APA in 24 out of 90 NHL patients (26.6%). Elevated APA were more often detected in women and in the elderly. The presence of elevated APA was not correlated with the histology and the stage of the lymphoma. None of the 24 patients with elevated APA developed a thromboembolic event in the follow-up period. Thromboembolic events were observed in 12 patients (13.3%), all with negative APA. High APA titres and the combination of positive aCL- and anti-beta2-GPI antibodies, features which are known to be more strongly correlated with thrombosis among patients with antiphospholipid syndrome and systemic lupus erythematous (SLE), were very uncommon in our cohort of NHL patients (3.3%). Vessel compression by lymphoma but not elevated APA remains the main cause of thrombosis in NHL patients.

Recurrent stroke and vascular events in elderly patients with anticardiolipin antibodies: a prospective study.

The presence of anticardiolipin antibodies (aCL) is a recognized risk factor for ischaemic stroke and a predictor of recurrent ischaemic events in young patients, but the significance of positive aCL tests is uncertain in the elderly. We evaluated the frequency of aCL and the risk of recurrence of stroke and other vascular events in a series of 242 consecutive patients aged over 60 years, admitted for brain infarction. All underwent aCL immunoreactivity (ELISA; measured by IgG antiphospholipid, GPL, units) and transoesophageal echocardiography and were later examined or contacted by telephone (mean 2.33 +/- 1.25 years, max. 4). Fifty patients (21 %) had at least l0 GPL units aCL. There were no differences between these and the other patients in the results of transoesophageal echocardiography, including mitral or aortic valvular thickening, atrial thrombus, atrial spontaneous contrast, strands, and aortic plaques thickness. None had IgG higher than 80 GPL units or was positive for anti-beta2 glycoprotein I. Patients with at least 10 GPL units more often had a past history of cerebral infarction than patients lower aCL level. However, the incidence of recurrent stroke was 4.5 per 100 person-year in patients with more than 10 GPL units, and 2.7 per 100 person-year in those with more than 10 GPL units. Kaplan-Meier analysis for any vascular events showed no differences between the two groups. In contrast to young patients, elderly patients with 10 or more GPL units aCL and negative for anti-beta2 glycoprotein I do not seem to have a higher risk of vascular events.

Lipoprotein (a) and anticardiolipin antibodies are risk factors for clinically relevant restenosis after elective balloon percutaneous transluminal coronary angioplasty

Recent reports have shown the importance of new risk factors for cardiovascular disease. We investigated the relationship between Lp(a), fibrinolytic parameters and anticardiolipin antibodies (aCL) and the occurrence of clinical recurrence owing to restenosis after elective balloon percutaneous transluminal coronary angioplasty (PTCA) without stenting. In 167 patients, undergoing PTCA, Lp(a) plasma levels, aCL, euglobulin lysis time (ELT), plasminogen activator inhibitor-1 (PAI-1) activity and tissue-type plasminogen activator (t-PA) plasma levels were evaluated before the procedure. During follow-up 29 patients underwent clinical recurrence due to restenosis. Lp(a) levels were significantly higher in patients with restenosis in comparison to those without ( P<0.05); an earlier restenosis was observed in patients with Lp(a) values >450 mg/L. Kaplan–Meier survival estimate showed an earlier occurrence of restenosis in patients with base-line Lp(a)>300 mg/l associated with aCL positivity. High Lp(a) plasma levels play a role in the occurrence of clinical recurrence due to restenosis after elective balloon PTCA without stenting; the association with aCL accelerates the development of restenosis.

Anticardiolipin antibodies in patients with chronic hepatitis C virus infection: characterization in relation to antiphospholipid syndrome.

The antiphospholipid syndrome (APS) is usually defined by the association of clinical manifestations that comprise venous and/or arterial thrombosis, recurrent fetal losses, and thrombocytopenia, along with the presence of anticardiolipin (aCL) antibodies and/or lupus anticoagulant. Various infectious diseases can induce aCL; however, these antibodies are not usually associated with thrombotic events, as happens with autoimmune diseases, in which these antibodies need the presence of beta(2)-glycoprotein I. Levels of immunoglobulin G (IgG) and IgM aCL antibodies were determined by enzyme-linked immunosorbent assay for 243 patients with chronic hepatitis C virus (HCV) infection and 100 healthy controls. Clinical events of APS, the level of beta(2)-glycoprotein dependence of aCL, the presence of cryoglobulins and other autoantibodies, and cross-reactivity between purified aCL and HCV were evaluated. Positive results for aCL antibodies were found more frequently (3. 3%) for the patients with HCV infection than for healthy controls (0%). All positive aCL antibodies were beta(2)-glycoprotein I independent. No significant association was found between aCL antibodies and clinical manifestations of APS, neither was one found between the presence of other autoantibodies or cryoglobulins and that of aCL. Finally, no cross-reactivity between aCL antibodies and HCV antigens was observed. As previously reported, aCL antibodies seem to be an epiphenomenon, and they do not have clinical or laboratory significance in HCV patients.

Testing for the antiphospholipid syndrome: importance of IgA anti-beta 2-glycoprotein I.

Testing for the antiphospholipid syndrome (APS) using anticardiolipin antibodies (aCL) has been problematic. Titers may fluctuate or even become negative. Anti-beta 2-glycoprotein I assays (abeta2-GPI) may be more reliable for diagnosis. In a prospective, blinded study over a nine-month period we retested all patients seen for routine follow-up visits in our clinic who had previously been evaluated for aCL-associated illnesses. Patients were stratified into two groups: group A-patients previously positive for aCL; group B-patients previously negative for aCL. Both groups were further classified according to disease severity. Patients were retested for both aCL and abeta2-GPI (isotypes G, M, A for each) using uniform testing standards. 118 patients with previously positive aCL (group A) were retested. Repeat aCL were positive in 52/118 (44%), abeta2-GPI positive in 69/118 (58%) and 82/118 (69.5%) were positive for one or both assays. In patients with serious organ damage (92% with documented APS), 48.6% were aCL positive, 64% positive for abeta2-GPI, and 75.7% were positive for one or both assays. When only one assay was positive, abeta2-GPI was most frequent (P=0.0096). Overall, IgA abeta2-GPI was the most frequent isotype found (60.9%). On retesting of 73 aCL-negative patients (group B), 9/73 (12%) were aCL positive, 27/73 (36%) were abeta2-GPI positive, with 24/73 (32.9%) having isolated abeta2-GPI. Of those positive for abeta2-GPI, IgA abeta2-GPI was present in 74. 1%. Many of these patients had documented APS. Based on our data, abeta2-GPI assays are superior to aCL assays for diagnosis of APS. The combined use of both assays enhance positive testing results in up to 75% of patients with APS at any stage of illness. ACL negative patients suspected of having APS should be retested for both abeta2-GPI and aCL. IgA abeta2-GPI appears to be the most important isotype detected.

Evaluation of antibodies to beta2-glycoprotein 1 in the causation of coronary atherosclerosis as part of the antiphospholipid syndrome.

Anticardiolipin antibodies (aCL) are associated with accelerated coronary atherosclerosis. Beta2-glycoprotein 1 is a cofactor necessary for the binding of aCL. The aim of this study was to determine whether antibodies to beta2-glycoprotein 1 (anti-beta2GP1) predispose to coronary artery disease (CAD), and whether the measurement of anti-beta2GP1 will be more useful than aCL alone in the evaluation of coronary risk. Persons who had undergone coronary angiography were invited to participate, and risk factors for coronary atherosclerosis recorded. IgG aCL and anti-beta2GP1 were measured and fasting triglyceride (TG) and total cholesterol (TC) levels were determined. Angiographic score (AS) was defined as the number of diseased vessels (0, 1, 2, 3), (>50% stenosis). Ethics Committee approval was obtained. Statistical comparison used the Student's t test and Chi-squared test. Ninety-seven subjects (63 male) with age range 38-81 years (mean 66.0) participated. There were 31 subjects with AS=0, 27 with AS=1, 22 with AS=2, and 17 with AS=3. The three subjects with positive aCL all had CAD, as did three of the four subjects with positive anti-beta2GP1. Among patients with CAD, there was an equal incidence (4.5%, three/66) of aCL and anti-beta2GP1, and an incidence of either aCL or anti-beta2GP1 of 7.6% (five/66). Compared to the group with AS=0, those with AS=1, 2 or 3 comprised a higher mean age (p=0.001) however, there was no significant difference in the prevalence of other coronary risk factors between the two groups. There was no difference in the proportions of patients with either aCL or anti-beta2GP1 in the group with AS=1, 2, or 3, compared to the group with AS=0 (5/66 c.f. 1/31, chi2=0.146, p>0.5). Our study has not supported an association between anti-beta2GP1 and CAD. The measurement of anti-beta2GP1 (or aCL) in the investigation of premature CAD is not justified on the basis of our results.

Anticardiolipin antibodies in hemodialysis patients

END-STAGE renal disease (ESRD) patients are known to have a higher frequency of elevated anticardiolipin antibodies (aCL) compared with the general population. The prevalence of elevated aCL in hemodialysis (HD) patients exceeds that of ESRD patients who are on conservative treatment. The proportion of individuals with positive tests for aCL has been identified as significantly higher in patients on regular HD compared with those on continuous ambulatory peritoneal dialysis (CAPD). Many abnormalities of the hemostatic system have been described in patients with liver disease. One study found that aCL positivity was more common (22%) in a group of patients with chronic hepatitis C virus (HCV) infection than in healthy subjects. Elevated levels of aCL are reportedly associated with thrombotic events as well, including myocardial infarction, portal or hepatic vein thrombosis, deep venous thrombosis, and pulmonary embolism. The aims of this study were to assess the prevalence of IgG and IgM aCL positivity in HD and CAPD patients, to identify any existing correlation between aCL level and HCV infection, and to determine whether thrombotic events are correlated with aCL levels.

Abstracts of literature

Abstracts of literature

Anticardiolipin antibodies, free protein S levels and thrombosis: a survey in a selected population of rheumatoid arthritis patients.

To investigate plasma levels of natural anticoagulant proteins such as protein S, protein C and antithrombin III in a selected population of patients with rheumatoid arthritis (RA) with and without anticardiolipin antibody (aCL) positivity, and to evaluate the possible relationships with an increased risk of thrombotic events in RA. A total of 184 female RA patients attending our Extra-Articular Involvement RA Clinic were evaluated for aCL levels, total and free protein S, protein C and antithrombin III concentrations, and for the occurrence of thrombotic events. Patients were grouped as aCL positive (n = 35) and aCL negative (n = 149). Higher rates of venous and/or arterial thromboses were diagnosed in patients with RA compared to controls (P = 0.01). In particular, lower free protein S levels were found in aCL-positive patients with RA compared to both aCL-negative patients and controls (P = 0.001). Functional assays for protein C, antithrombin III as well as total protein S levels were found to be in the normal range in all patients and controls. The association observed between aCL positivity and decreased levels of free protein S in RA patients may represent one of the risk factors for thrombotic events.

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

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. 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). 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. 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.

IgA Anticardiolipin and Anti-β2-Glycoprotein I Are the Most Prevalent Isotypes in African American Patients with Systemic Lupus Erythematosus

BackgroundEthnicity plays a role in the prevalence, isotype distribution, and clinical significance of anticardiolipin (aCL) and anti-β2-glycoprotein I (anti-β2-GPI) antibodies in patients with systemic lupus erythematosus (SLE). Few studies have been done in the African American population MethodsSerum samples from 100 African American patients with SLE were tested for IgG, IgM, and IgA aCL and anti-β2-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). ResultsPositivity 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-β2-GPI antibodies. IgA was the most prevalent isotype for both antibodies; 24% of the patients in the aCL ELISA and 19% in the anti-β2-GPI ELISA were positive for IgA. Positivity for both aCL and anti-β2-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-β2-GPI antibodies (P = 0.02). No other manifestations of APS could be significantly correlated with the presence of these antibodies. ConclusionsOur 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.