IgM aCL Research Articles

Antiphospholipid antibodies in patients with autoimmune blistering disease

Our purpose was to determine the serum levels and frequency of antiphospholipid antibodies (aPLs) and confirm the clinical importance of these antibodies in patients with autoimmune blistering disease (ABD). IgG and IgM anticardiolipin antibodies (aCL), IgG anticardiolipin-beta(2) glycoprotein I complex antibody (aCL/beta(2)GPI), and IgG antiphosphatidylserine-prothrombin complex antibody (aPS/PT) were examined with an enzyme-linked immunosorbent assay in 71 patients with ABD, including pemphigus vulgaris, pemphigus foliaceus, and bullous pemphigoid. The prevalence of IgG aCL, IgM aCL, aCL/beta(2)GPI, and IgG aPS/PT was positive for 22.4%, 9.1%, 9.9%, and 25.4% of the ABD patients, respectively, whereas these antibodies were not detected in any of the normal control subjects. Ten of 20 patients with ABD who were attending our hospital in 2004 tested positive for aPLs, and thromboembolism was detected in 7 of 10 patients with aPLs. Follow-up studies, especially with a large patient group, will be needed to clarify the clinical relevance of aPLs in ABD. aPLs are frequently detected in patients with ABD. Careful examination and follow-up for thromboembolism may be necessary in ABD patients with aPLs.

Anti-prothrombin antibodies predict thrombosis in patients with systemic lupus erythematosus: a 15-year longitudinal study.

To evaluate the role of anti-prothrombin (anti-PT) antibodies in predicting thrombosis in patients with systemic lupus erythematosus (SLE). An inception cohort of 101 SLE patients (12 males, 89 females; mean age 30 +/- 8 years), was considered. Clinical and laboratory evaluations were regularly performed during a 15-year follow-up (median 108 months) with a special focus on thromboembolic events. Serum samples were collected at time of diagnosis and at least once a year thereafter. IgG and IgM anti-PT, anti-cardiolipin (aCL) and anti-beta(2)glycoprotein I (beta(2)GPI) antibodies were measured by enzyme-linked immunosorbent assay (ELISA); lupus anticoagulant (LAC) was assayed by the dilute Russell's viper venom time and activated partial thromboplastin time tests. The analytical specificity of anti-PT ELISA was investigated. The timing of thrombosis occurrence was calculated using the Kaplan-Meier method. In the 15-year follow-up, thrombosis occurred in 14 out of the 101 patients: venous thrombosis in nine cases and arterial thrombosis in five. IgG and/or IgM anti-PT, anti-beta(2)GPI and aCL antibodies, and LAC activity were detected in ten, nine, seven, and nine cases, with sensitivity for thrombosis of 71.4%, 64.3%, 50% and 64.3%, respectively. Thrombosis-free survival was 90% at 5 years and 85.8% at 10 and 15 years, respectively. Thrombosis was predicted by anti-PT (P = 0.001), anti-beta(2)GPI antibodies (P = 0.002) and LAC activity (P = 0.001). Moreover, the risk of thrombosis progressively increased with the number of positive antiphospholipid antibody tests. The presence of four positive antibody tests was associated with a risk of thrombosis thirtyfold higher than in their absence. This longitudinal study shows that IgG anti-PT antibodies are predictors of thrombosis in SLE patients.

Specificity and sensitivity of anti-β2-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.

Prevalence of Anticardiolipin and Anti-β2-Glycoprotein I Antibodies in Celiac Disease

The aim of this study was to evaluate the prevalence of anticardiolipin antibodies (aCL) and anti-beta(2)-glycoprotein I antibodies (abeta2GPI) in patients with celiac disease and to analyze the clinical features of antiphospholipid syndrome in these patients. We conducted a prospective case-control study based on the evaluation of IgG, IgM and IgA aCL, and IgG and IgA abeta2GPI in celiac disease patients and in controls. All patients were asked about any occurrence of thrombotic manifestations. In addition, women were asked about pregnancy morbidity. Fifty celiac disease patients and 50 healthy controls were studied. IgM aCL were not detected in study group or in controls. IgG aCL were found in two patients and in one control. IgA aCL were significantly more frequent in celiac disease patients compared with controls (13/50 (26%) vs. 2/50 (4%), p=0.004, OR [95% CI]=9.09 [1.81-50]). There was no statistically significant difference for the prevalence of IgG and IgA abeta2GPI between patients and controls. Clinical features of antiphospholipid syndrome were noted in two patients with negative antibodies. Prevalence of IgM and IgG aCL and of abeta2GPI were not increased in celiac disease. IgA aCL were more frequently detected in celiac disease. However, no clinical features of antiphospholipid syndrome were noted.

Antibodies to β 2-glycoprotein-I: Relation of anticardiolipin antibodies with clinical and laboratory parameters in patients with systemic lupus erythematosus

Objectives: There are controversial reports on the frequency of antiphospholipid antibodies (aPL) in patients with systemic lupus erythematosus (SLE). Thus, we aimed to determine the frequency and clinical importance of aPL isotypes in Turkish patients with SLE. Design and methods: Fifty-nine patients with SLE and 41 healthy controls were included. Serum aPL levels were measured both in patients and healthy subjects by ELISA. Results: Fifteen of the patients with SLE had the antiphospholipid syndrome (APS) (25.4%). The percentage of anticardiolipin antibody (aCL)-positive SLE patients among all patients was 56%. At least one isotype of anti-β 2-glycoprotein I (β 2-GPI) antibody was positive in 83% of patients. The positivity rates of aCL and anti-β 2-GPI antibodies in patients with or without APS were higher than the healthy controls. There were positive correlations between isotypes of IgM aCL, IgG and IgM anti-β 2-GPI and manifestations of APS. Conclusion: It seems that the isotypes of IgM aCL, IgG and IgM anti-β 2-GPI are correlated with manifestations of APS. They may play a role in pathogenesis and may be helpful in establishing the diagnosis.

Cross-sectional analysis of adverse outcomes in 1,029 pregnancies of Afro-Caribbean women in Trinidad with and without systemic lupus erythematosus

The objective of the study was to examine pregnancy outcomes in women with systemic lupus erythematosus (SLE) and population controls in Trinidad. We performed a cross-sectional analysis of adverse outcomes in pregnancies of Afro-Caribbean women with SLE and without SLE. One hundred and twenty-two female adult cases of SLE and 203 neighbourhood age-matched women without SLE were interviewed concerning details of their reproductive history, and the anticardiolipin antibody (ACL) status was established for women with SLE. A total of 1,029 pregnancies were reported (356 by women with SLE, 673 by women without SLE). In women with ≥ 1 pregnancy the total number of pregnancies was similar in women with a diagnosis of SLE and women without; however, a lower proportion of women with SLE had ever been pregnant compared with women without SLE (80% versus 91%, P = 0.002). In multivariate logistic regression analyses adjusted for maternal age, district of residence, pregnancy order and smoking, SLE pregnancies were more than twice as likely to end in foetal death than non-SLE pregnancies (odds ratio (OR), 2.4; 95% confidence interval (CI), 1.2–4.7). This effect was driven by a large increase in the odds of stillbirth (OR, 8.5; 95% CI, 2.5–28.8). The odds of early miscarriage (OR, 1.4; 95% CI, 0.6–3.1) and of mid-trimester miscarriage (OR, 1.9; 95% CI, 0.4–9.5) were higher, but were not statistically significantly different, in SLE pregnancies than in non-SLE pregnancies. The odds of ectopic pregnancy (OR, 7.5; 95% CI, 0.9–62.5) and of preterm birth (OR, 3.4; 95% CI, 1.2–10.0) were higher in SLE pregnancies conceived after diagnosis than in non-SLE pregnancies. There was no evidence of raised levels of IgG or IgM ACL among the majority (93/97 women, 96%) of SLE cases who reported sporadic mid-trimester miscarriage or stillbirth, although there was evidence of high levels of IgM and IgG ACL among women reporting three or more miscarriages and three consecutive miscarriages, and of raised IgG ACL among those experiencing ectopic pregnancy. In conclusion, we found evidence for a large increase in risk of stillbirth in the pregnancies of Afro-Caribbean Trinidadian women with SLE (not accounted for by high ACL status). There was some evidence of an increased risk of preterm delivery and ectopic pregnancy in pregnancies conceived after a diagnosis of maternal SLE.

Effects of short‐term infliximab therapy on autoantibodies in systemic lupus erythematosus

To analyze changes in autoantibodies occurring in patients with systemic lupus erythematosus (SLE) treated with 4 infusions of the chimeric anti-tumor necrosis factor alpha (TNFalpha) antibody infliximab. In an open-label safety study, 7 patients with SLE were treated with infliximab at weeks 0, 2, 6, and 10 in combination with azathioprine or methotrexate. Antibodies to double-stranded DNA (dsDNA) were determined by radioimmunoassay and the Crithidia luciliae indirect immunofluorescence assay; anticardiolipin antibodies (aCL) and antibodies to histone and chromatin were measured by enzyme-linked immunosorbent assay. Antihistone antibodies were also analyzed by immunoblotting. Peripheral blood mononuclear cells from healthy individuals and SLE patients were incubated for 2 weeks with or without TNFalpha. TNFalpha was removed by washing and by the addition of infliximab. Apoptotic cells were stained with annexin V and analyzed by flow cytometry. Autoantibodies to dsDNA increased in 5 of 7 patients. Histone, chromatin, and IgM aCL levels were increased in 4 of 7, 6 of 7, and 4 of 7 patients, respectively, peaking 4-10 weeks after the last infliximab infusion, but falling to baseline levels or lower thereafter. In the in vitro experiments, TNF withdrawal after long-term incubation with recombinant human TNF led to increased percentages of apoptotic cells. While TNF blockade was clinically effective, the majority of SLE patients treated with infliximab showed an increase in autoantibodies to nuclear antigens and phospholipids. These increases were transient and were not associated with disease flares. Increased availability of apoptotic antigens after TNF blockade may play a role in the autoantibody formation induced by TNF blockade.

Detection of Antiphospholipid Antibodies Using a Novel Multiplex Test Method: Correlation with ELISA Methods.

-Background: Laboratory criteria for the antiphospholipid antibody syndrome (APS) include detection of the lupus anticoagulant (LA) by coagulation based tests, or detection of either anti-cardiolipin (aCL), or anti-B2-glycoprotein I (aB2GPI) antibodies by enzyme-linked immunoabsorbant assay (ELISA). Multiplex testing enables simultaneous measurement of multiple serum antibodies with small beads coated with target antigens and small sample volumes (5 μL). We compared the concordance of a prototype multiplex method to standard ELISA methods for measuring IgG and IgM antibodies directed against CL or B2GPI.Methods: Samples from patients with suspected APS were tested for IgG and IgM aCL and aB2GPI antibodies using standard ELISA methods (ELISA, Bio-Rad Laboratories, Hercules, CA) and by a prototype multiplex bead set analyzed on the BioPlex 2200 (Bio-Rad Laboratories, Hercules, CA). The multiplex method used beads coated with either CL alone, B2GPI alone, or CL-B2GPI complex. Results were normalized using ratios (obtained result/upper limit of normal). A positive result was defined as a ratio of > 1. For CL, the multiplex test is considered positive if positive results are present using beads with either the CL alone or the CL-B2GPI complex.Results:Table 1Concordance of ELISA vs Multiplex tests for antiphospholipid antibody detectionMultiplex Test ResultsConcordance (%)ELISA Test ResultsPositiveNegativePositiveNegativeAll ResultsaCL-IgGPositive (n=52)302258-Negative (n=232)32200-8682aCL-IgMPositive (n=42)321076-Negative (n=241)34207-8584aβ2GPI-IgGPositive (n=34)201459-Negative (n=249)17232-9389aβ2GPI-IgMPositive (n=61)313051-Negative (n=219)22197-9081Conclusions: The overall concordance of multiplex results with ELISA results was good (81–89%). Negative multiplex results showed excellent correlation with ELISA (85–93%). Positive multiplex results had variable correlation with ELISA (51–76%). Evaluation of clinically significant positive results and clinical outcome measures is needed to determine clinical sensitivity and specificity of the multiplex test. Further refinement of the multiplex platform may provide an efficient and cost-effective assay for antibodies associated with the antiphospholipid syndrome.

IgG and IgM anticardiolipin antibodies following treatment with infliximab plus methotrexate in patients with early rheumatoid arthritis

To assess the occurrence of anticardiolipin antibodies (aCL) in patients with early rheumatoid arthritis (RA) receiving treatment with infliximab plus methotrexate (MTX) versus MTX alone. The first 299 patients enrolled in the randomized, Active-Controlled Study of Patients Receiving Infliximab for the Treatment of Rheumatoid Arthritis of Early Onset (ASPIRE) trial who had baseline (week 0) samples available for aCL testing were included in this study. Sera were collected at weeks 0, 30, and 54 from 110 patients taking infliximab 3 mg/kg plus MTX, 98 patients taking infliximab 6 mg/kg plus MTX, and 91 patients taking placebo plus MTX. IgG and IgM aCL were measured using an anticardiolipin assay. IgG and IgM aCL positivity at baseline was similar in all treatment groups. Most patients were negative for IgG aCL at baseline and remained so at the last followup evaluation. One percent (2 of 208) of patients who received infliximab plus MTX and were negative for IgG aCL at baseline were positive for IgG aCL at weeks 30 and 54. A slightly higher proportion of patients who received infliximab plus MTX and were negative for IgM aCL at baseline were positive for IgM aCL at weeks 30 and 54 (4.8% [10 of 208]) as compared with patients who received placebo plus MTX (1.1% [1 of 91]), but the difference was not significant. There was a low incidence of the development of aCL in patients with early RA who received infliximab in combination with MTX, and the difference was not significant compared with patients who received placebo plus MTX.

Elevated serum IgA anticardiolipin antibody levels in adult Henoch-Schönlein purpura

Henoch-Schönlein purpura (HSP) is a small-vessel vasculitis characterized by palpable purpura on the lower extremities and IgA-dominant immune complex deposition within the wall and lumen of dermal vessels in the lesions. This disorder is associated, to varying degrees, with joint, gastrointestinal and renal involvement. Antiphospholipid antibodies, including anticardiolipin antibodies (aCL Abs), are a heterogeneous group of circulating autoantibodies found in patients with autoimmune and infectious diseases. To investigate the possible role of aCL Abs in adult HSP, we measured levels of serum IgA, C-reactive protein (CRP), aCL Abs of the IgG, IgM and IgA isotypes and anti-beta(2)-glycoprotein I (beta(2)GPI)-dependent aCL Abs in adult patients with HSP. We evaluated the correlation between these biological parameters and the clinical manifestations. Adult patients with HSP with an initial cutaneous manifestation of palpable purpura on their lower extremities seen between 2001 and 2005 in our department were retrospectively reviewed. Patients with known connective tissue diseases were not included in the study. Histological examination of all patient skin biopsy specimens revealed leucocytoclastic vasculitis in the upper and mid-dermis. Direct immunofluorescence analysis showed prominent deposits of IgA in the capillary walls of all patients. Blood samples were taken at the time that the patient presented. Serum levels of aCL Abs and anti-beta(2)GPI-dependent aCL Abs were measured by enzyme-linked immunosorbent assay. Twenty adult patients with HSP (12 men and eight women), mean age 62.2 years (range 23-81) were enrolled. IgA aCL Abs were found in 15 of the 20 patients (75%). All were negative for IgG aCL Abs, IgM aCL Abs and anti-beta(2)GPI-dependent aCL Abs. The elevation of serum IgA aCL Abs in the 15 patients showed a significant correlation with serum IgA and CRP levels (r(s) = 0.91, P = 0.0007; r(s) = 0.80, P = 0.0026, respectively). Levels of serum IgA aCL Abs were also significantly associated with arthralgia (P = 0.022) and proteinuria according to urinalysis (P = 0.013). Serum levels of IgA aCL Abs are elevated in the initial active stage of adult HSP, suggesting that serum IgA aCL Abs may play some role in the onset of adult HSP. We believe that serum IgA aCL Abs might be an indicator of adult HSP activity.

Significance of antiprothrombin antibodies in patients with systemic lupus erythematosus: clinical evaluation of the antiprothrombin assay and the antiphosphatidylserine/prothrombin assay, and comparison with other antiphospholipid antibody assays

Antibodies against prothrombin are detected by enzyme immunoassays (EIA) in sera of patients with antiphospholipid syndrome (APS). However, there are two methods for antiprothrombin EIA; one that uses high binding plates (aPT-A), and another that utilizes phosphatidylserine bound plates (aPS/PT). We aimed to evaluate and compare aPT-A and aPS/PT in a clinical setting. We performed EIA for anti-PT, anti-PS/PT, IgG, and IgM anticardiolipin antibodies (aCL), and IgG β2-glycoprotein I-dependent aCL (aβ2GPI/CL) with serum samples from 139 systemic lupus erythematosus (SLE) patients (16 with history of at least one thrombotic episode) and 148 controls. We observed that: (1) although titers of anti-PT and anti-PS/PT were significantly related with each other (P < 0.0001, ρ = 0.548), titer of anti-PT and anti-PS/PT differed greatly in some samples; (2) odds ratio and 95% confidence interval for each assay was 3.556 (1.221–10.355) for aPT-A, 4.591 (1.555–15.560) for aPS/PT, 4.204 (1.250–14.148) for IgG aCL, 1.809 (0.354–9.232) for IgM aCL, and 7.246 (2.391–21.966) for aβ2GPI/CL. We conclude that, while all EIA performed in this study except IgM aCL are of potential value in assessing the risk of thrombosis, aPS/PT and aβ2GPI/CL seemed to be highly valuable in clinical practice, and that autoantibodies detected by anti-PT and anti-PS/PT are not completely identical.

Significance of antiprothrombin antibodies in patients with systemic lupus erythematosus: clinical evaluation of the antiprothrombin assay and the antiphosphatidylserine/prothrombin assay, and comparison with other antiphospholipid antibody assays

Antibodies against prothrombin are detected by enzyme immunoassays (EIA) in sera of patients with antiphospholipid syndrome (APS). However, there are two methods for antiprothrombin EIA; one that uses high binding plates (aPT-A), and another that utilizes phosphatidylserine bound plates (aPS/PT). We aimed to evaluate and compare aPT-A and aPS/PT in a clinical setting. We performed EIA for anti-PT, anti-PS/PT, IgG, and IgM anticardiolipin antibodies (aCL), and IgG β2-glycoprotein I-dependent aCL (aβ2GPI/CL) with serum samples from 139 systemic lupus erythematosus (SLE) patients (16 with history of at least one thrombotic episode) and 148 controls. We observed that: (1) although titers of anti-PT and anti-PS/PT were significantly related with each other (P < 0.0001, ρ = 0.548), titer of anti-PT and anti-PS/PT differed greatly in some samples; (2) odds ratio and 95% confidence interval for each assay was 3.556 (1.221–10.355) for aPT-A, 4.591 (1.555–15.560) for aPS/PT, 4.204 (1.250–14.148) for IgG aCL, 1.809 (0.354–9.232) for IgM aCL, and 7.246 (2.391–21.966) for aβ2GPI/CL. We conclude that, while all EIA performed in this study except IgM aCL are of potential value in assessing the risk of thrombosis, aPS/PT and aβ2GPI/CL seemed to be highly valuable in clinical practice, and that autoantibodies detected by anti-PT and anti-PS/PT are not completely identical.

Clinical manifestations and antiphosphatidylserine antibodies in patients with systemic lupus erythematosus: is there an association?

Antiphospholipid antibodies are a group of heterogeneous autoantibodies which have been reported in systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) in association with thrombosis, fetal loss, and thrombocytopenia. In this study, we aimed to reveal the prevalence and correlation of IgG, IgA, and IgM isotypes of antibodies to cardiolipin (aCL) and antiphosphatidylserine (aPS) with clinical and laboratory manifestations of SLE patients. Fifty-nine SLE patients and 41 healthy controls were included. Fifteen of patients (25.4%) had secondary APS. aCL and aPS antibody assays were performed by enzyme-linked immunosorbent assay. All isotypes of aCL and aPS antibodies except IgG were higher in patients with or without APS than those in the healthy controls (p<0.001). The most significant associations were found among migraine and IgA aCL (p<0.001), livedo reticularis and both IgM aCL and IgM aPS (p<0.001), migraine and IgM aCL (p<0.01), pulmonary involvement and IgM aCL (p<0.01), migraine and IgA aPS (p<0.01), and both thrombosis and migraine with IgM aPS (p<0.01). A relatively high prevalence of aCL and aPS antibodies was found in our SLE patients. It seems that isotypes of IgM aCL, IgM aPS, IgA aCL, and IgA aPS antibodies are correlated well with migraine and IgM aPS with thrombosis in SLE patients with secondary APS. The assessment of both IgM and IgA isotypes of aPS and aCL antibodies may be helpful in predicting these manifestations.

Presence of high avidity anticardiolipin antibodies in patients with autoimmune cholestatic liver diseases

We studied the prevalence and clinical significance of anticardiolipin antibodies (aCL) in primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) as similar data are missing. Ninety-nine PBC patients, 41 PSC, 228 HCV, 50 HBV, 111 with other non-viral and non-autoimmune liver disorders and 267 healthy were investigated. In order to evaluate the avidity of aCL, urea 2 M was used. IgG and/or IgM aCL were detected in 40% of PBC and PSC patients, in 26.2% of disease controls ( P < 0.05) and 2.25% of healthy ( P < 0.05). In PBC, IgG aCL associated with presence of cirrhosis, increased Mayo risk score and thrombocytopenia, while in PSC with longer disease duration and biochemical activity. Anti-β 2-GPI was detected in only three patients. Both in PBC and PSC, resistance of aCL to urea was high, similar to that observed in antiphospholipid syndrome (APS). We demonstrated a significantly higher prevalence of aCL in PBC and PSC compared to other liver diseases and healthy. aCL were associated with more severe disease in PBC and biochemical activity in PSC, but they rather seem to be “non-pathogenic” (co-factor-independent). However, their avidity was comparable with that of APS, indicating the need for prospective studies in order to address whether aCL in PBC and PSC may contribute to APS development or the progression of hepatic disease.

Antiphospholipid antibodies may be a new prognostic parameter in aggressive non‐Hodgkin's lymphoma

Patients with malignancies have an increased prevalence of antiphospholipid antibodies (APA). The aim of this study was to determine the prevalence of IgG, IgM, and IgA anticardiolipin antibodies (aCL) and anti-beta-2 glycoprotein I antibodies (anti-beta2-GPI) in patients with non-Hodgkin's lymphoma (NHL), and to investigate their clinical and prognostic significance. The study group included 86 patients with NHL. Enzyme-linked immunosorbent assay kits were used to measure the concentrations of aCL and anti-beta2-GPI, and coagulation tests, to measure lupus anticoagulant (LAC) activity. Blood was collected at diagnosis in all patients and at follow-up in 15. Median follow-up time was 1.9 yr. Elevated APA levels were found in 35 patients (41%) at diagnosis: one patient aCL IgG, five patients aCL IgM, five aCL IgA, one anti-beta2-GPI IgG, 14 anti-beta2-GPI IgM, and 19 anti-beta2-GPI IgA; LAC activity was found in three of 67 patients (4.5%). There was no significant correlation between elevated APA levels and patient's age or sex, disease stage or grade, bone marrow involvement, B symptoms, serum lactate dehydrogenase levels, serum beta2 microglobulin levels, International Prognostic Index (IPI) score, performance status, type of treatment, or response to treatment. There was a correlation between elevated APA and absence of extranodal disease (P = 0.045). A strong negative correlation was found between elevated APA at diagnosis and survival time. Two-year survival was 90 +/- 5% for patients without APA at diagnosis compared with 63 +/- 11% for patients with an elevated APA levels (P = 0.0025). APA added to the predictive value of IPI for event-free and overall survival. APA are elevated in 41% of NHL patients at diagnosis and are correlated with shortened survival. Their level may serve as an independent prognostic variable in aggressive NHL.

Complement-fixing activity of anticardiolipin antibodies in patients with and without thrombosis

We have analysed in vitro the complement-fixing activity of anticardiolipin antibodies (C-fix aCL) from patients with persistent and moderate/high titres IgG aCL antibodies: 21 with thrombosis and 11 without thrombosis. Titre and C-fix ability of aCL were measured by ELISA. APS and non-APS patients were similar with regard to mean levels of IgG aCL (46 +/- 24 versus 51 +/- 30 GPL, P = 0.7), frequency of IgM aCL (P = 0.7) and a comparable predominance of IgG2 aCL reactivity on ELISA (95% versus 100%, respectively, P = 1.0). Remarkably, a high frequency of C-fix aCL (71% versus 92%, P = 0.35) was observed in both groups. Similarly, no difference was observed in the mean level of C-fix aCL in APS and non-APS patients (7 +/- 6 versus 9 +/- 8 SDunits, P = 0.3). Analysis of 10 primary and 11 secondary APS also revealed a comparable IgG aCL mean titre (57 +/- 29 versus 37 +/- 11, P = 0.06), frequency of IgM aCL (P = 0.6) and of C-fix aCL (70% versus 73%, P = 0.99). Among APS patients six had exclusive arterial events and seven exclusive venous events. The IgG aCL mean titre (36 +/- 10 versus 36 +/- 11 GPL, P = 0.9) and the frequency of IgM aCL antibodies (P = 0.56) in these subgroups of patients were comparable. There was a trend of higher frequency of C-fix aCL in patients with exclusive venous events (100%) compared to 50% of those with exclusive arterial events (p = 0.07). Importantly, C-fix aCL titre was higher in the former group compared to the later one (8 +/- 5 SDunits versus 2 +/- 2 SDunits, P = 0.016). Our data support the notion of a high frequency of C-fix aCL in APS. Although it does not discriminate those patients without thrombotic events with persistent moderate/high levels of aCL, this property seems to be more relevant in venous events and may provide the basis for further understanding the distinct pathogenic mechanisms underlying arterial and venous occlusive disorders of APS.

The Behavior of Anticardiolipin Antibodies Levels in Patients with Venous Thromboembolism.

The aim of this study was to investigate anticardiolipin (aCL) (IgG and IgM) levels in patients with objectively confirmed venous thromboembolism (VTE). aCL IgG and IgM were measured using an in-house ELISA assay. When aCL levels were ≥10 U, a second measurement was performed using another sample at least 6 weeks after the first test. Patients tested twice with aCL levels ≥10 U were classified as having positive aCL and those with only one measurement ≥10 U had transitory aCL. aCL was evaluated in 282 outpatients with VTE, with median age of 39 years (range:15–94), 66.7% were women. We found 28 patients (9.9%) with positive aCL (IgG in 5.6%, IgM in 1.8% and IgG + IgM in 2.5%) and 29 (10.3%) with transitory aCL (IgG in 5.3%, IgM in 3.2% and IgG + IgM in 1.8%). The association of systemic disease with VTE had a significant effect on the occurrence of transitory aCL (OR= 3.6; 95%CI: 1.5–8.8), but not on positive aCL (OR= 1.7; 95%CI: 0.6–5.0). There was a significant correlation between the first and second measurements for IgG (rs= 0.58; p < 0.0001) and for IgM (rs= 0.49; p = 0.011). Patients with IgG < 30 GPLU showed a higher risk of having transitory aCL (OR= 4.9; 95%CI: 1.2–19.7; p= 0.027), and this effect was more pronounced in patients with IgM < 30 MPLU (OR=15; 95%CI: 1.2 – 113.6; p= 0.008). In conclusion, prevalence of transitory aCL was as high as positive aCL in patients with VTE, mainly among those with IgG or IgM < 30 U. Higher aCL levels were more frequently associated with repeatedly positive aCL. Transitory aCL was more frequent in the presence of systemic disease associated with VTE, which could reflect an epiphenomenon, whereas repeatedly positive aCL could play a more important role in the genesis of VTE.

Takayasu’s arteritis associated with antiphospholipid antibodies

The finding of elevated level of antiphospholipid antibodies (APLAs) in a proportion of Takayasu’s arteritis (TA) patients suggests a contribution of APLAs in vascular injury at least in some of TA patients [1–3]. However, these findings have not been confirmed in other series of TA [4]. The controversy regarding the APLAs in TA is in part due to the small number of reported TA patients with APLAs assayed, and therefore we present a TA patient with increased levels of APLAs and lupus anticoagulant (LAC). In 2001 a 27-year-old woman developed Raynaud’s phenomenon, claudication of both upper extremities and visual disturbances. The complains started during the last 3 months of her the only pregnancy and she delivered a healthy child. She presented at hospital in January 2003 with absence of radial and brachial pulses in both upper extremities and vascular bruits over the right carotid and both subclavian arteries (SCA). Femoral and dorsum pedis pulses were palpable and blood pressure was 160/95 mm Hg on both legs. Color Doppler sonography: occlusion of the left common carotid artery (ACC), internal carotid artery (ACI) and external carotid artery (ACE), concentric thickening of the right ACC, ACI and ACE, stenosis of both SCA. The flow through both verterbral arteries (VA) was normal with a poststenotic spectrum type. Descending aorta and renal arteries were normal. Transcranial Doppler sonography: poststenotic spectra in both middle and posterior cerebral arteries. Angiography (Fig. 1): occlusion of ACC and left SCA, circular narrowing of the right ACC and narrowing of the right SCA to the origin of VA. Collateral circulation with retrograde flow through the left VA to the left SCA. Funduscopy: left, optic disc atrophy; right, diffuse small hemorrhages and extravasations. Erythrocyte sedimentation rate (ESR) was 85 mm/h and C-reactive protein (CRP) level was 19.1 mg/l (normal <5 mg/l). Platlets count was normal. Antinuclear antibody, antiSmith antibody, and anti dsDNA were negative. C3 and C4 levels were normal. Circulating immunocomplex level was 7.3 lg/ml (normal <5). The patient possessed B8 and DR3 HLA alleles Lupus anticoagulant and anticardiolipin antibodies (aCLa) were positive in two subsequent measurements ( IgM aCL 157 and 172 IU/ml, normal <100; IgG aCL 95 and 93 IU/ml; normal <100). Therapy included methylprednisolone (pulses 1 g i.v./ 3 days, 1 mg/kg body weight/day/4 weeks followed by 6 mg/day orally), cyclophosphamide (1 g i.v. every 4 weeks), and methotrexate 10 mg weekly. Ethylbuscomate was given for positive LAC and aCL antibodies although there was no manifest thrombosis. In the course of therapy, a moderate improvement of carotid flow and laboratory test normalization (ESR 6 mm/h, CRP 4 mg/l) occurred. One month latter, at home, the patient suddenly lost consciousness with epileptic attack. She died few hours later, most likely due to ischemic brain insult; autopsy was not performed. In our patient, the diagnosis of TA (type III according to Ishisawa) relied on her clinical data meeting all American College of Rheumatology 1990 criteria [5], J. Morovic-Vergles Department of Clinical Immunology and Rheumatology, University Department of Medicine, School of Medicine, University of Zagreb, Zagreb, Croatia

Prevalence of antibodies against oxidised LDL in a cohort of 163 patients with positive anti-phospholipid antibodies and recent thrombosis

We evaluated the prevalence of anti-beta2-glycoprotein I (a-beta2-GPI), anti-phosphatidylserine/prothrombin (a-PP), anti-prothrombin (a-PT), and anti-oxidised low-density lipoprotein (a-oxLDL) antibodies in a cohort of patients with a recent thrombotic event. Among consecutive sera sent to an autoimmune laboratory for routine testing for anti-cardiolipin antibodies (aCL) 473 were found positive for IgG and/or IgM aCL. The referring physicians were requested for clinical information about thrombo-embolic events occurring within 6 months prior to testing. One hundred and sixty-three individuals of which 82 had suffered from cerebro-vascular infarction and 49 from deep venous thromboses or pulmonary emboli were included in the study. Ninety-four sera were positive for IgG aCL and 69 were negative. There was a strong correlation between the presence of IgG aCL and the three other phospholipid-related antibodies: a-beta2-GPI, a-PP, and a-PT. However, IgG a-oxLDL antibodies were almost equally distributed among sera positive and negative for IgG aCL. The presence of antibodies of all subgroups was most pronounced among patients with venous thrombo-embolic disease. In this cohort antibodies to beta2-GPI, PP, PT seem to coexist with aCL. However, a-oxLDL antibodies appear to define a subset of patients, who were older, had more arterial vascular disease, and with no apparent association to the presence of IgG aCL.

IgG and IgM isotypes of anti-cardiolipin and anti-β 2-glycoprotein i antibodies reflect different forms of recent thrombo-embolic events

We correlated the distribution and levels of serum anti-cardiolipin (aCL) and anti-beta(2)-glycoprotein-1 antibodies (anti-beta(2)-GPI) of the IgG and IgM isotypes to the clinical spectrum of recent (<6 months) thrombo-embolic events in a cohort of 162 patients. Clinical information was obtained by questionnaires from the referring physicians. Cerebro-vascular infarction (CVI) had taken place in 82 patients, deep venous thrombosis (DVT) in 34, pulmonary embolism (PE) in 14, myocardial infarction (MI) in four, and other thromboses in 28 patients. SLE was the most commonly associated rheumatic disease and accounted for 20 (12%) patients. In 124 (77%) patients no underlying rheumatic disease was identified. Isolated IgG aCL was found in 31 of 48 patients with DVT/PE (65%), but in only 21 of 82 patients with CVI (26%); p<0.0001. IgG anti-beta(2)-GPI were detected in 23 (48%) DVT/PE patients, but in only 13 (16%) CVI patients; p<0.001. The IgG class anti-beta(2)-GPI positive patients had significantly higher levels of IgG aCL (mean 65 units) compared to IgG anti-beta(2)-GPI negative patients (mean 29 units); p<0.0001. In contrast, isolated IgM aCL was found in nine (19%) patients with DVT/PE, but in 46 (56%) CVI patients; p<0.0001. Only ten patients had IgM anti-beta(2)-GPI. The present study shows that the IgG and IgM aCL isotypes seem to define different clinical subsets of patients with thrombo-embolic events with IgG aCL being most prevalent in the group having DVT/PE, IgM aCL being found primarily among CVI patients.