IgG aCL Antibodies Research Articles

High titer of anti–phosphatidylserine‐prothrombin complex antibodies in patients with cutaneous polyarteritis nodosa

To investigate possible correlations between cutaneous polyarteritis nodosa (CPN) and antiphospholipid syndrome-associated antibodies. Sixteen patients were referred with CPN features. To investigate the possible role of antiphospholipid antibodies (aPL) in CPN, we measured serum lupus anticoagulant (LAC), IgG and IgM anticardiolipin (aCL) and anti-phosphatidylserine-prothrombin complex (anti-PS/PT) antibodies, and anti-beta(2)-glycoprotein I-dependent cardiolipin (anti-beta(2)GPI/CL) antibodies in the 16 CPN patients, 8 microscopic polyangiitis (MPA) patients, 33 systemic lupus erythematosus (SLE) patients, and 23 healthy controls. LAC was determined according to the Subcommittee on Lupus Anticoagulant/Phospholipid Dependent Antibody guidelines. Anti-PS/PT, aCL, and anti-beta(2)GPI/CL antibodies were measured by enzyme-linked immunosorbent assay. Anti-PS/PT antibodies and/or LAC were detected in all CPN patients, but not in any controls. Serum IgM anti-PS/PT antibody was found in 13 (81.3%) CPN patients. The mean +/- SD serum anti-PS/PT IgM level (19.9 +/- 12.4 units/ml) in CPN patients was significantly elevated compared with SLE patients (5.7 +/- 5.9 units/ml). IgG anti-PS/PT antibody was detected in 5 (31.3%) CPN patients, but not in any controls. The IgG PS/PT antibody titers were similar in CPN patients (12.3 +/- 12.0 units/ml) and SLE patients (13.8 +/- 14.3 units/ml). Three (18.8%) CPN patients were positive for IgG aCL antibody and 2 (12.5%) for IgM aCL antibody. No MPA patients had aPL. CPN skin manifestations included livedo reticularis (14 [87.5%]). Direct immunofluorescence (DIF) revealed C3 within the affected vessels in 7 (77.8%) of 9 CPN patients. Our study demonstrated that presence of anti-PS/PT antibodies and/or LAC could serve as markers in CPN patients. CPN could be dependently associated with the presence of anti-PS/PT antibody. Clinicians need to recognize these titers to permit early accurate diagnosis and treatment. We believe that anti-PS/PT antibodies will become widely recognized as a new factor when diagnosing CPN.

“Acute Phase Lipids” associated with phospholipids of Cardiolipins in sera of patients with Chronic Fatigue Syndrome (CFS) and other diseases

Interest in the study of lipids in CFS serum was initiated when it was shown that the lipids demonstrated an immunological reaction with MAb-CTX (monoclonal antibody to Ciguatoxin) associated with Ciguatera Fish Poisoning (CFP). CTX is a lipid marine toxin that is considered to be a neurotoxin. We have examined 328 CFS sera in a study with 17 CFP, 8 Gulf War, 24 Prostate Cancer, and 52 normal sera in the modified Membrane Immunobead Assay (MIA) procedure for CTX. Lipids from serum are extracted with 4 parts acetone to 1 part serum. The solution is shaken thoroughly and the suspension centrifuged at 1000 rpm for 10 minutes. The acetone phase is decanted into a tared 10 ml test tube and the acetone evaporated by a stream of air in a hood overnight. The dried lipid phase is weighed and recorded. The highest dilution showing color (+/−) with the MAb-CTX beads is scored as the end titre. A titre ≥ 1:40 is considered positive for “Acute Phase Lipids.” 328 CFS patient’s sera were examined by the modified MIA with purified MAb-CTX and 91% gave a titre ≥ 1:40.76% of the 17 CFP sera samples and 100% of the 8 Gulf War sera samples also had a titre ≥ 1:40.92% of 52 normal sera showed titres of 1:20 or less, while 4 gave titres of ≥ 1:40. In addition, 41 sera were examined for Anti-Cardiolipin (aCL) by a commercial ELISA procedure with 87.8% demonstrating IgM, IgM + IgA, or IgM +IgG aCL antibodies. These results showed mostly the IgM antibody in the samples. Preliminary chemical analyses have shown the lipids to be phospholipids associated with cardiolipin of the mitochondrial phospholipid. We designate this lipid, “Acute Phase Lipid” comparable to “Acute Phase Proteins” (CRP and SAA) in inflammatory conditions. [Supported, in part, by National CFIDS Fdn, Needham MA, and the Hokama-Yagawa Fund, UH Fdn]

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.

Antiphospholipid antibody ELISAs: Survey on the performance of clinical laboratories assessed by using lyophilized affinity-purified IgG with anticardiolipin and anti-β 2-Glycoprotein I activity

Lupus anticoagulant (LA) and anticardiolipin (aCL) antibodies are the classical tests used to diagnose the antiphospholipid syndrome (APS). Unfortunately, since these are nonspecific and standardization is lacking, the results of laboratory work-ups upon which diagnosis are made are often misleading. The performance of clinical laboratories in detecting LA using lyophilised affinity purified immunoglobulin has been previously reported. The same material was used to investigate the inter-laboratory variability of aCL and anti-β 2-Glycoprotein I (β 2-GPI) antibody measurements. Laboratories were asked to test normal plasma spiked with purified IgG or distilled water in order to obtain 3 samples positive for aCL and anti-β 2-GPI at different antibody concentration (A, B and C) and 3 samples of normal plasma. Thirty-five laboratories participated and interpreted their test results. All performed an ELISA for IgG aCL antibodies, while 17 also tested samples using IgG anti-β 2-GPI antibody ELISA. Sensitivity and specificity were calculated on the basis of the responses provided by each laboratory. Overall, 99/105 samples were correctly interpreted as positive and 97/101 as negative for the presence of IgG aCL, corresponding to a sensitivity and specificity of 94% and 96%, respectively. Likewise, 46/51 samples were correctly defined as positive and 50/51 as negative for the presence of IgG anti-β 2-GPI corresponding to a sensitivity and specificity of 90% and 98%, respectively. A wide variability in results pertaining to the positive samples was found for aCL-ELISA (coefficient of variation of 79%, 59%, and 53% for samples A, B, and C, respectively) as well as for aβ 2-GPI-ELISA (coefficient of variation of 85%, 95%, and 50% for samples A, B, and C, respectively). This was confirmed when the analysis was restricted to those centres using the same commercial kit. Median antibody concentrations reported by centres for positive samples were consistent with the prolongation of coagulation tests assessing lupus anticoagulant (LA). Among these, dRVVT showed a good sensitivity and linear correlation with aCL antibody concentration. In conclusion, on the whole this survey found correct interpretation of positive and negative samples by both ELISAs. Nonetheless the high variability of reported data remains a major problem that only a consensus on the part of laboratories and manufacturers to utilize standard, uniform materials and procedures can hope to overcome.

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 Relationship Between Anticardiolipin Antibodies and Vascular Access Occlusion in Patients on Hemodialysis

Vascular access occlusion is frequently seen in some patients on hemodialysis. There are different opinions about pathogenesis of recurrent access thrombosis. Anticardiolipin (aCL) antibodies have been suggested to be involved in thrombosis and can be found in a high proportion of patients with chronic renal failure. We investigated the relationship between vascular access occlusion and the level of aCL antibodies in hemodialysis patients. We measured serum IgG and IgM aCL antibodies and protein C levels in 50 patients on hemodialysis having no fistule thrombosis (group 1), in 33 patients on hemodialysis with fistule thrombosis (group 2), and 20 nondialyzed patients with chronic renal failure (group 3). There were no differences in age and duration on hemodialysis (p > 0.05). No significant correlation was found between protein C and platelet counts in all groups (p > 0.05). In group 1, aCL IgG and IgM were 2%. In group 2, aCL IgG and IgM were 6.06% and 0%, respectively. In group 3, aCL IgG and IgM were negative. We did not find any significant difference between aCL IgG and IgM in all groups (p > 0.05). No association was found between aCL antibodies and vascular access thrombosis in our patients on hemodialysis.

Thrombosis in systemic lupus erythematosus: Congenital and acquired risk factors

To investigate the thrombotic tendency in patients with systemic lupus erythematosus (SLE) by evaluating congenital or acquired abnormalities associated with an increased risk of venous and/or arterial thrombosis. A total of 57 patients with SLE were included in the study. Twenty-one patients (37%) had a history of arterial and/or venous thrombosis and 36 patients (63%) did not have such a history. Sera from 50 healthy controls were examined. Protein C, protein S, antithrombin, D-dimer, fibrinogen, homocysteine, anticardiolipin antibodies (aCL), lupus anticoagulant (LAC), prothrombin G20210A, and methylenetetrahydrofolate reductase (MTHFR) C677T gene mutation were evaluated. Protein C, antithrombin, fibrinogen, D-dimer, and homocysteine levels were significantly higher in patients with SLE than in controls. A prothrombin mutation was observed in 2 (4%) of 50 controls and in 6 (11%) of 57 patients. A significantly higher prevalence (P = 0.036) of MTHFR homozygous mutation was observed in patients with SLE (14 [25%] of 57) in comparison with controls (4 [8%] of 50). IgG-aCL and IgM-aCL levels were significantly higher in patients with SLE than in controls (P < 0.0001). The presence of medium-high (> or = 20 IgG phospholipid units/ml) IgG-aCL antibody titers was significantly higher (P = 0.005) in patients with thrombosis (11 [52%] of 21) than in patients without (5 [14%] of 36) thrombosis. LAC was present in 22 (38.5%) of 57 patients and in none of 50 controls. In this study, we confirm the association between thrombosis and IgG-aCL at medium-high titers and suggest that the coexistence of other risk factors can affect the expression of thrombosis in patients with SLE.

The Coinicidence of Venous and Arterial Thrombosis in Patients with Antiphospholipid Syndrome - Correlation with Laboratory Findings.

The antiphospholipid syndrome (APS) is one of the most common acquired causes of thrombosis on the venous or arterial site. The initial type of the thrombosis appears to be the most likely type of event to recur. In general, APS patients present more common venous thrombosis, especially deep vein thrombosis of the legs. Arterial thromboses are less common and mostly manifest with ischemia or infarction. It is not clear whether a combination of phospholipid antibodies or the additional presence of lupus anticoagulants in patients with anticardiolipin antibodies increase the risk of manifestation of APS.Methods: We investigated retrospectively 300 patients with elevated aCL antibodies. IgG and IgM aCL antibodies were tested by enzyme-linked immunosorbent assay (ELISA). LA were tested by more than 2 different methods according to the proposed criteria of the SSC of the ISTH.Results: Of these patients, 61 % suffered from manifestations of APS, 35 % from venous and 28 % from arterial thrombosis, 7 % of the patients had abortions. In 39 % no thromboembolic disease was found. The coincidence of venous and arterial thrombosis was found in 25/300 (8 %) of the patients. An increased titer of IgG aCL was found in 135 of 300 patients (45 %, median 49 GPL-U/ml, normal range: - 11,3 GPL-U/ml), and an increased titer of IgM aCL in 260 patients (87 %, median 13 MPL-U/ml, normal range: 5,6 MPL-U/ml). Lupus anticoagulants were additionally detected in 130/300 patients (43 %). The rate of clinical manifestations did not differ between LA-positive patients (78 of 130 patients, 60 %) and LA-negative patients (105 of 170, 62 %) patients with elevated aCL antibodies. Regarding the patients with the coincidence of venous and arterial thrombosis, we found a significantly higher rate of positive lupus anticoagulants than in the patients with APS manifestation of one site only (17/25 vs. 113/275, p < 0.05, OR 3.04; 95 % CI 1.31 – 7.06). An elevation of IgG-aCL titres were more frequently found, too.Table 1: Characteristics of the patients with a coincidence of venous and arterial thrombosis compared to patients with thrombosis of one site onlyConclusion: The additional presence of lupus anticoagulants in patients with anticardiolipin antibodies identifies a group of patients with high risk of recurrent manifestations of the antiphospholipid syndrome. Particularly the risk of manifestation of both, arterial and venous thrombosis in these patients should be early recognized to initiate a careful follow-up and antithrombotic therapy in these patients.Venous and Arterial ThrombosisThrombosis of One SiteNo APS Manifestationn25/300 (8 %)157/300 (59 %)118/300 (39 %)Age (yrs) median48.55046Sex (F/M)17/8 (2.1)62/157 (2.1)51/118 (2.3)LA17/25 (68 %)62/157 (39 %)51/118 (43 %)IgG-aCL15/25 (60 %)73/157 (46 %)47/118 (40 %)median titre108 GPL87 GPL37 GPLIgM-aCL24/25 (96 %)129/157 (82 %)104/118 (88 %)median titre13 MPL14 MPL14 MPL

Trends of anticardiolipin antibodies after low-dose methylprednisolone and cyclophosphamide treatment of systemic lupus erythematosus

The aim of the study is to analyze retrospectively the effect of low-dose methylprednisolone (MP) and cyclophosphamide (CYC) pulse therapy on anticardiolipin antibodies (aCL) serum levels in patients with systemic lupus erythematosus (SLE). For aCL determinations, a beta2-glycoprotein I-dependent enzyme-linked immunosorbent test (ELISA) was performed. Lupus anticoagulant was investigated by Russell venom time with platelet neutralization. Antinuclear antibodies were performed by standardized methods. All SLE patients (from a total of 137) with aCL determinations who were assayed before and after MP and CYC pulse therapy were included in the study. Nine patients had aCL determinations before and after MP-CYC pulse therapy. All active patients with SLE improved clinically without severe MP-CYC side effects; 21 had IgG-aCL determinations, and 19 IgM-aCL determinations (40 assays) were performed in all nine patients during the observation period (zero time to 21 months). Three patients had secondary antiphospholipid syndrome (APLS)-related clinical manifestations. In all patients, IgG aCL antibodies decreased significantly (p <0.05). Decrease of IgG aCL serum levels as a consequence of the MP-CYC therapy herein reported might help to redefine previous concepts with regard to modulation of antiphospholipid antibody (aPL) immune response by immunosuppressive therapy. These findings might also have prognostic and therapeutic implications in SLE, on pregnancy in SLE, and in antiphospholipid syndrome (APL) as well, although prospective studies are required.

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

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). 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. 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). 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.

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.

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.

Catastrophic Antiphospholipid Syndrome

Catastrophic Antiphospholipid Syndrome

Anticardiolipin antibodies and recurrent coronary events: a prospective study of 1150 patients. Thrombogenic Factors, and Recurrent Coronary Events Investigators.

The association of anticardiolipin (aCL) antibodies with coronary artery disease has been shown in several studies but remains controversial. We evaluated the association of aCL and anti-beta(2)-glycoprotein I (abeta(2)GPI) antibodies with the risk of recurrent cardiac events in postinfarction patients. The study population consisted of 1150 patients with acute myocardial infarction. Levels of IgG and IgM aCL and abeta(2)GPI antibodies were determined on sera collected before hospital discharge. There were 131 recurrent cardiac events (nonfatal myocardial infarctions or cardiac deaths) over a mean follow-up period of 24.6 months. Patients with elevated IgG aCL antibodies had a higher event rate than patients with low levels (P:=0.05). Multivariate Cox analysis after adjustment for relevant clinical covariates showed that elevated levels of IgG aCL (hazard ratio=1. 63; P:=0.01) and low levels of IgM aCL (hazard ratio of 1.76; P:=0. 02) antibodies contribute independent risks for recurrent cardiac events. Patients with elevated IgG aCL and low IgM aCL antibody levels had a 3-fold higher risk of recurrent cardiac events than patients with low IgG aCL and elevated IgM aCL antibody levels (P:<0. 001). There was no significant association of the abeta(2)GPI antibodies with recurrent cardiac events. In postinfarction patients, elevated IgG aCL and low IgM aCL antibodies are independent risk factors for recurrent cardiac events. Patients with both elevated IgG aCL and low IgM aCL antibodies have the highest risk. These findings shed additional light on the mechanistic role of aCL antibodies in coronary artery disease in patients without autoimmune diseases.

The prevalence of antibodies to anionic phospholipids in patients with the primary antiphospholipid syndrome, systemic lupus erythematosus and their relatives and spouses.

Antiphospholipid antibodies (aPL) have been associated with syndromes involving thrombosis, fetal loss and thrombocytopenia. Genetic and environmental conditions are among the factors attributed to the cause of autoimmune diseases such as the antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE). The aim of this study was to determine whether these factors determine the prevalence of aPL. Three groups of patients were tested for the presence of IgG, IgM and IgA anticardiolipin (aCL), antiphosphatidylinositol (aPI), antiphosphatidylglycerol (aPG) and antiphosphatidylserine (aPS) antibodies: (i) patients with primary APS (PAPS); (ii) patients with SLE and secondary APS; and (iii) patients with SLE without APS. First-degree relatives and spouses of patients with SLE/APS were also tested for circulating aPL. IgG aPL were particularly prevalent in patients with PAPS. IgG aPI and aCL were more prevalent in patients with PAPS than the IgM equivalents (P < 0.0001). Notably, none of the patients with PAPS had IgA aPL. A significantly higher number of relatives of patients with SLE/APS possessed IgG aPL than the normal controls. Except for aPG (P < 0.03), the prevalence of these antibodies in the relatives was not significantly different from patients with SLE/APS. The relatives also had significantly higher prevalence of IgG aPI, aPS and aCL antibodies than IgM aPL antibodies. In contrast, the prevalence of IgG aPL in the spouses was no different than in the healthy controls. Genetic factors, shared by patients and their relatives, seem to have some effect on the prevalence of aPL in the subjects studied, while environmental factors shared by spouses appear to have no influence.

A chimeric antibody with the human gamma1 constant region as a putative standard for assays to detect IgG beta2-glycoprotein I-dependent anticardiolipin and anti-beta2-glycoprotein I antibodies.

Thromboembolic manifestations or thrombocytopenia in association with anticardiolipin antibodies (aCL) or lupus anticoagulant are known as the antiphospholipid syndrome (APS). Efforts have been made to elucidate precise clinical features and adequate therapeutic options for treating patients with APS. However, the lack of a proper international standard for measurement of aCL makes it difficult to compare data derived from different laboratories. We attempted to design a chimeric antibody with human gamma constant regions and variable regions of WBCAL-1, a monoclonal antibody established from an APS-prone mouse which has a specificity similar to that of aCL in sera from humans with APS. Variable-region genes of WBCAL-1, which were cloned using reverse transcription-polymerase chain reaction, were inserted into plasmids containing human gamma1 and kappa constant-region genes. The construct was transfected to a mouse myeloma cell line. Stable transfectants that secreted a chimeric antibody, HCAL, into the culture supernatant were obtained. The reactivity of HCAL to cardiolipin and to beta2-glycoprotein I (beta2GPI) was studied using a solid-phase enzyme immunoassay. The binding of HCAL was compared with the binding of standards for IgG aCL and anti-beta2GPI antibody assays done in 18 independent laboratories. In the presence of beta2GPI, HCAL bound to the wells of cardiolipin-coated microtiter plates in a dose-dependent manner and reacted with beta2GPI on oxygenated polystyrene plates. The aCL activity of HCAL can be converted into GPL units (IgG phospholipid units), which is widely used to quantify IgG aCL activity, using the following formula: 1 GPL unit = 32.9 x (concentration of HCAL [in microg/ml])(0.503). The reactivity of HCAL to cardiolipin or beta2GPI was similar to the reactivity of standards for IgG aCL or anti-beta2GPI antibody assays done in collaborative laboratories. Because the reactivity of HCAL is similar to that of aCL in sera from humans with APS, HCAL will be useful as a standard for human IgG aCL and anti-beta2GPI antibody assays.

False-Positive Reactions for IgA Anti-Phospholipid and Anti-β2-Glycoprotein I Antibodies in Patients with IgA Monoclonal Gammopathy

We report here that measurements of IgA anti-cardiolipin (aCL) and anti-β2-glycoprotein I (β2GPI) antibodies are unreliable in patients with IgA monoclonal gammopathies (MGs). MGs are characterized by monoclonal immunoglobulins produced by a proliferating B-lymphocyte clone. Monoclonal gammopathy of undetermined significance (MGUS) is the most common type of MG (1); the monoclonal component (MC) is IgA in 15–25% of MGs (2). aCL antibodies, originally described in patients with systemic lupus erythematosus (3), have been detected in patients with other autoimmune diseases (4)(5) and in the antiphospholipid syndrome (6)(7) as well as in nonrheumatologic disorders (8) and in healthy individuals (9)(10)(11). In patients with connective tissue diseases and antiphospholipid syndrome, aCL antibodies are most frequently IgG, followed by IgM. Kalunian et al. (12), however, reported a high incidence of IgA, rather than IgG-aCL antibodies associated with thrombosis and fetal loss, and other reports have suggested that IgA-aCL antibodies may have a clinical meaning even in the absence of IgG- or IgM-aCL (13)(14)(15)(16)(17)(18)(19)(20)(21). Their prevalence in healthy subjects seems negligible; in a series of 389 healthy pregnant women, Lynch et al. (22) found only one positive case (0.3%). Therefore, to properly assess the risk of thrombosis, thrombocytopenia, and recurrent abortions in systemic lupus erythematosus patients, the determination of IgA-aCL antibodies has been recommended (18)(21). Very recently, the same recommendation was also made for anti-β2GPI antibody determination because anti-β2GPI restricted to the IgA isotype can be found in the sera of systemic lupus erythematosus patients with thrombosis (23). IgG- or IgM-aCL activity has been described occasionally in subjects with MG (24)(25)(26)(27), but …

Prevalence and Signification of Antinuclear and Anticardiolipin Antibodies in Patients with Epilepsy

PURPOSE:To determine the prevalence of autoantibodies in patients with epilepsy and to find a possible relationship between antinuclear antibodies (ANA) and/or anticardiolipin (aCL) antibodies and epilepsy.PATIENTS AND METHODS: One hundred sixty-three consecutive, unselected patients followed at the Centre Saint-Paul, a French medical center specialized in epilepsy, were included in the study. IgG and IgM class aCL antibodies were measured by an enzyme-linked immunosorbent assay (ELISA). IgG class ANA was detected by an indirect immunofluorescence technique with Hep2 cells as the substrate. Sera from 100 healthy blood donors, matched for age and sex, were used as controls.RESULTS: In 31 sera, IgG class aCL antibodies were detected at a value higher than 17 GPL unit (19%, P = 0.0003); 10 of them had a value higher than 35 GPL unit. IgM class aCL antibodies were not detected at a significant value. For 6 of the 31 sera, there was a β2-glycoprotein I dependence. None of the patients with aCL antibodies in the serum had a past history of deep venous or arterial thrombosis. ANA were detected in the sera from 41 patients (25%, P < 0.005). The presence of autoantibodies in the serum was not statistically dependent on the type of epilepsy, the kind of antiepileptic drug, or the age or sex of the patients.CONCLUSIONS: Our study suggests that there is a relationship between epilepsy and aCL antibodies, even in the patients without systemic lupus erythematosus. Large prospective studies are needed to define the role of the aCL antibodies and ANA in pathophysiology of epilepsy.

Association between IgM anticardiolipin antibodies and deep venous thrombosis in patients without systemic lupus erythematosus.

Patients with systemic lupus erythematosus (SLE) are at risk of developing deep venous thrombosis (DVT). Should anticardiolipin antibodies (aCL) be detectable, this risk is significantly raised, particularly when these autoanti-bodies are cofactor-dependent. We conducted a cross-sectional study of consecutive unselected outpatients referred for clinical suspicion of DVT, as an attempt to address the following questions: firstly, were aCL antibodies associated with DVT in non-SLE patients? Secondly, was this association related to the cofactor dependence? From March 1992 to February 1994, 208 patients were enrolled in the study. Venography was positive in 110 patients (DVT patients), while the diagnosis of DVT could not be confirmed in the remaining 98 (referred to as disease controls). ACL was measured by ELISA, for IgG and IgM isotypes in two ways: fetal calf serum or bovine serum albumin were used as blocking agents to distinguish between cofactor-dependent and cofactor-independent antibodies. Positive aCL was defined as optical density (OD) values greater than the 95th percentile of OD distribution of 60 healthy controls. We found a high frequency of positive IgG aCL antibodies in both DVT patients and in disease controls (25.5 vs 23.5%). We suggest an association between IgM aCL and DVT. This association was, however, not dependent on the cofactor requirement.

Elevated levels of anticardiolipin antibodies and epilepsy in lupus patients.

To examine the association between anticardiolipin (aCL) antibodies and epilepsy, we investigated the serum titers of aCL antibodies in a total 252 systemic lupus erythematosus (SLE) patients recruited in a prospective study. Twenty-one cases with epilepsy which were not attributable to any causes other than SLE were identified after being followed-up for five years. The clinical manifestations were recorded and blood samples were tested for the presence of aCL antibodies (IgG, IgM and IgA isotypes). Among 21 patients with epilepsy, 12 (57.1%), 2 (9.5%) and 2 (9.5%), respectively, had elevated baseline serum levels of IgG, IgM and IgA aCL antibodies. There was a dose-response relationship between risk of seizure and the baseline serum level of aCL antibodies (P < 0.01). The odds ratio of developing seizure were 3.7 for those who had a high level of aCL antibodies compared with those without a detectable level of aCL antibodies as the referent. Our results indicate that epilepsy as a primary neuropsychiatric event among lupus patients is associated with a high titer of aCL antibodies.