aCL Levels Research Articles

Evolution of disease burden over five years in a multicenter inception systemic lupus erythematosus cohort

We describe disease activity, damage, and the accrual of key autoantibodies in an inception systemic lupus erythematosus (SLE) cohort. The Systemic Lupus International Collaborating Clinics (SLICC) International Research Network, comprising 27 centers from 11 countries, has followed an inception cohort of SLE patients yearly according to a standardized protocol. Of these patients, 298 were followed for a minimum of 5 years and constitute the study population. Disease activity was assessed using the SLE Disease Activity Index 2000 (SLEDAI-2K) and damage was assessed using the SLICC/American College of Rheumatology Damage Index (SDI). Antinuclear antibody (ANA), anti-DNA, and anticardiolipin antibody (aCL) levels and lupus anticoagulant were assessed yearly. Descriptive statistics were generated and repeated-measures general linear models were used to evaluate SLEDAI-2K and SDI over time between whites and nonwhites. Of the 298 patients, 87% were women, 55% were white, 12% were African American, 14% were Asian, 16% were Hispanic, and 2% were categorized as "other." At enrollment, the mean age was 35.3 years, the mean SLEDAI-2K score was 5.9, and the mean disease duration was 5.5 months. Mean SLEDAI-2K scores decreased in the first year and then remained low. SLEDAI-2K scores were significantly lower at each year in whites compared to nonwhites. Mean SDI scores increased progressively over 5 years; there was no significant difference between whites and nonwhites. As expected, ANA positivity was high and anti-DNA positivity was relatively low at enrollment, and both increased over 5 years. Although lupus anticoagulant increased slightly over 5 years, aCL positivity did not. Disease activity in newly diagnosed patients decreases over their first 5 years, while damage increases. Antibody positivity ran variable courses over this period.

Engraftment of peripheral blood mononuclear cells from systemic lupus erythematosus and antiphospholipid syndrome patient donors into BALB‐RAG‐2−/−IL‐2Rγ−/− mice: A promising model for studying human disease

To construct a humanized mouse model of systemic lupus erythematosus (SLE) that resembles the human disease in order to define the pathophysiology and targets for treatments. We infused peripheral blood mononuclear cells (PBMCs) from SLE patients into BALB- RAG-2-/- IL-2Rγ-/- double-knockout (DKO) mice, which lack T cells, B cells, and natural killer cells. PBMCs from 5 SLE patients and 4 normal donors were infused intravenously/intraperitoneally at a density of 3-5×10(6) cells per animal into nonirradiated 4-5-week-old mice. We evaluated the engraftment of human CD45+ cells and monitored the plasma levels of human IgG, anti-double-stranded DNA (anti-dsDNA) antibody, and anticardiolipin antibody (aCL), as well as proteinuria and kidney histology. There was 100% successful engraftment in 40 DKO mice infused with human PBMCs. In the PBMC fraction from SLE PBMC-infused DKO (SLE-DKO) mice and normal donor PBMC-infused DKO (ND-DKO) mice, an average of 41% and 53% human CD45+ cells, respectively, were observed at 4 weeks postengraftment, with 70-90% CD3+ cells. There were fewer CD3+CD4+ cells (mean±SEM 5.5±2.1%) and more CD3+CD8+ cells (79.4±3.6%) in the SLE-DKO mice as in the SLE patients from which the PBMCs were derived. CD19+ B cells and CD11c+ monocytic cells were found in the spleen, lung, liver, and bone marrow. There was no significant difference in plasma levels of human IgG and anti-dsDNA antibodies between SLE-DKO and ND-DKO mice. Levels of aCL were significantly higher in all SLE-DKO mice infused with PBMCs from an SLE patient who had high titers of aCL. SLE-DKO mice had proteinuria, human IgG deposits in the kidneys, and a shorter life span. In SLE-DKO mice engrafted with PBMCs from the aCL-positive patient, we found microthrombi and infiltration of CD3+, CD8+, and CD19+ cells in the glomeruli, recapitulating the human antiphospholipid syndrome in these mice. We established a novel humanized SLE-DKO mouse exhibiting many of the immunologic and clinical features of human SLE.

Ionising radiation triggers fat accumulation in white adipose tissue

Purpose: To investigate changes in gonadal white adipose tissue and lipogenesis-related gene expression induced by radiation exposure.Materials and methods: Groups of two-month-old C57BL/6 mice were exposed whole-body to 137Cs γ-rays at a single dose (5 gray [Gy]) or fractionated doses (1 Gy × 5 times, 0.5 Gy × 10 times, or 0.2 Gy × 25 times). Six months after irradiation, gonadal white adipose tissue was isolated from mice. Two and 25-month-old mice were used as young and old study references. Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was used to measure messenger RNA (mRNA) expression of genes related to: (i) Primary lipid metabolism (ATP-citrate lyase [ACL], malic enzyme1 [ME1] and glucose-6-phosphate dehydrogenase 2 [G6PD2]), (ii) glucose uptake (glucose transporter 4 [GLUT4]), (iii) fatty acid synthesis (sterol regulatory element binding transcription factor 1 [SREBP-1c], fatty acid synthetase [FAS] and acetyl-coenzyme A carboxylase beta [ACC]), (iv) triglyceride synthesis (diacylglycerol O-acyltransferase 1 [DGAT1] and diacylglycerol O-acyltransferase 2 [DGAT2]), and (v) adipose-derived hormones (leptin [LEP]).Results: The weight of gonadal white adipose tissue in the irradiated groups tended to increase compared to the non-irradiated group though the radiation-induced increase in white adipose tissue was only significant for the 5 × 1 Gy group. The mRNA levels of SREBP-1c, ACC, FAS, ACL, GLUT4, ME1 and G6PD2 were relatively lower in γ-irradiated groups than in non-irradiated groups. The mRNA levels of leptin and DGAT were relatively higher than non-irradiated groups. The changes in expression of these lipogenesis-related genes caused by γ-irradiation showed a very similar pattern to changes caused by ageing.Conclusions: A physical agent such as γ-rays can trigger biological responses resulting in fat accumulation of gonadal white adipose tissue in mice.

Frequency of anticardiolipin Ac in patients with hyperprolactinemia

Sir, Association between hyperprolactinemia and autoimmune diseases has been demonstrated.[12] We assessed the frequency of anticardiolipin (ACL IgG and IgM by ELISA) and thyroperoxidase (ATPO by chemiluminescence) antibodies, in 23 patients with hyperprolactinemia, subdivided into two groups: Group 1, untreated hyperprolactinemic patients (n = 14; 42.5 ± 14.7 years) and Group 2, treated hyperprolactinemic patients (n = 9, 39.4 ± 12.1 years). Group 3, control, consisted of 20 individuals without thyroid and autoimmune diseases (n = 20; 47.1 ± 13.6 years). Positivity of ACL was observed in none of the control, in two patients with treated hyperprolactinemia (one IgM and one IgG) and in one with treatment-free hyperprolactinemia (IgM) [Table 1]. ACL IgG levels were significantly higher in the group with hyperprolactinemia (2.1 ± 2.5 GPL) compared to the control group (0.7 ± 0.2 GPL), P = 0.018. ATPO was detected in 11/23 (47%) patients with hyperprolactinemia and in 1/20 (5%) of controls and the mean was significantly higher in the hyperprolactinemic group compared to control (P = 0.004).Table 1: Positivity and variation of the levels of anticardiolipin and thyroperoxidase in hyperprolactinemic and control groupsThe anticardiolipin antibody is organ-nonspecific, occurring in many autoimmune diseases such as rheumatoid arthritis and SLE, and in general population low levels of ACL (IgG < 4.3 μ/ml, IgM < 3.55 μ/ml and polivalent ACA < 4.55 μ/m) are described as well as positivity for IgM and IgG ACL around 4.6%.[3] In agreement we found no positivity of ACL in control group. Moreover, we detected positivity and mean level of ACL significantly higher in patients with hyperprolactinemia, treated or not, corroborating a previous study that reported positive results of ACL in 27% of women with hyperprolactinemia, with no symptoms of autoimmune diseases.[4] The result of the ACL presented here, as well as the knowledge that hyperprolactinemic individuals have significantly higher percentage of total lymphocytes and CD2-positive cells[2] and that levels of PRL in SLE patients are higher than in the general population[12] reinforce the immunomodulating role of prolactin, interacting with environmental and genetic factors for the development of autoimmune diseases. Increased levels of ATPO were detected in approximately half of patients with treated or untreated hyperprolactinemia. The presence of ATPO has already been linked to both hyperprolactinemia[4] and to the low reserve of PRL[5] and hyperprolactinemic women show higher prevalence of thyroid autoimmune disease than the general population.[4] Although some studies suggest that the presence of the ACL in thyroid autoimmune disease may be a non-specific marker for the activation of the immune system, this association is controversial and the influence of these antibodies in the course of thyroidopathy has not been totally explained yet. Data are conflicting regarding this issue, with reports of increased prevalence and no correlation between ACL and autoimmune thyroid disease.[6] The present findings of highest prevalence of ACL and ATPO in patients with hyperprolactinemia reinforce the concern over possible development of autoimmune diseases in prolonged hyperprolactinemia. However, the correlation between these factors remains unclear, suggesting the need for further studies.

Prevalence of anticardiolipin antibodies in type 1 diabetes and autoimmune thyroiditis

High levels of anticardiolipin (aCL) antibodies may predict vascular complications that could develop in type 1 diabetes and autoimmune thyroiditis (AIT). However, the clinical relevance of these antibodies in subjects with type 1 diabetes and AIT is unclear. The aim of the study was to determine the prevalence and significance of aCL antibodies in patients with type 1 diabetes and AIT. The study involved 74 patients with type 1 diabetes (mean age 12.9 +/-4.2 years), 64 patients with AIT (mean age 14.1 +/-3.7 years), and 35 healthy control subjects (mean age 12.8 +/-3.3 years). The levels of aCL immunoglobulin (Ig) G and aCL IgM antibodies were measured by enzyme-linked immunosorbent assays. Low-positive and medium/high-positive cut-off values were selected for aCL antibody positivity. The prevalence of aCL antibodies was higher in AIT patients compared with diabetic and healthy subjects with low positive levels (P <0.05), while the frequency of medium/high aCL positive levels in AIT and diabetic subjects was not statistically different from that observed in healthy subjects. Our study showed an increased prevalence of aCL antibody positivity in patients with AIT at a low-positive aCL cut-off level, while the frequency of aCL antibody positivity at a moderate/high aCL cut-off level was not significantly different between the groups. We believe that routine investigation of aCL levels may not have clinical relevance in children with type 1 diabetes or AIT.

Pioglitazone Attenuates Cystic Burden in the PCK Rodent Model of Polycystic Kidney Disease

Polycystic kidney disease (PKD) is a genetic disorder characterized by growth of fluid-filled cysts predominately in kidney tubules and liver bile ducts. Currently, the clinical management of PKD is limited to cyst aspiration, surgical resection or organ transplantation. Based on an observation that PPARγ agonists such as pioglitazone and rosiglitazone decrease mRNA levels of a Cl− transport protein, CFTR (cystic fibrosis transmembrane conductance regulator), and the Cl− secretory response to vasopressin in cultured renal cells, it is hypothesized that PPARγ agonists will inhibit cyst growth. The current studies show that a 7- or 14-week pioglitazone feeding regimen inhibits renal and hepatic bile duct cyst growth in the PCK rat, a rodent model orthologous to human PKD. These studies provide proof of concept for the mechanism of action of the PPARγ agonists and suggest that this class of drugs may be effective in controlling both renal and hepatic cyst growth and fibrosis in PKD.

Elevated anticardiolipin antibodies in schizophrenic patients before and during neuroleptic medication

The objective of this study was to examine the prevalence of IgG and IgM anticardiolipin antibodies (aCL) in schizophrenic patients and to determine the relation of aCL levels with neuroleptic medication and psychotic symptoms. Twenty-three patients with acute episodes of chronic schizophrenia, drug-free for at least 3 months before entering the study, were tested for aCL at admission (T1) and 42 days (T2) after neuroleptic treatment started. Blood samples were taken from 20 healthy volunteers as well. Diagnosis was performed according to DSM-IV. Serum samples were analysed for IgG and IgM autoantibodies against beta2-glycoprotein-1-cardiolipin complex by commercially available ELISA kits (Binding-site, UK). Significantly higher levels of aCL antibodies of both isotypes were found in schizophrenic patients versus controls. In patients IgM-aCL positivity was significantly more frequent than in controls. The elevated IgM-aCL and IgG-aCL values were not associated with neuroleptic treatment and psychotic symptoms, as measured by the Positive and Negative Syndrome Scale and the Pentagonal Structural Model of Schizophrenic Symptoms. The negative correlation of IgM-aCL and IgG-aCL with the positive symptoms scale and the autistic preoccupation scale (Pentagonal Structural Model) may indicate the consumption of these antibodies in the exacerbation of the disease.

Antiphospholipid antibodies in systemic sclerosis: a double oxidative hit?

In their paper regarding kidney function in systemic sclerosis (SSc) Wielosz et al. describe increased serum cystatin C and decreased glomerular filtration rate in SSc patients positive for antiphospholipid antibodies (aPL) measured as anti cardiolipin (aCL) and anti beta-2-glycoprotein I (β2GPI) compared to SSc patients negative for such aPL [1]. The authors found that serum IgG aCL positively predicted serum cystatin C and negatively creatinine clearance alongside IgG β2GPI. Moreover pulmonary arterial hypertension (PAH), proteinuria and scleroderma renal crisis were more frequent in aPL positive patients though none of the patients had clinical features of the antiphospholipid syndrome (APS) [1]. Other studies on SSc have described the occurrence of PAH more commonly in SSc patients positive for aPL [3–5] and for anti-phosphatidyl serine/prothrombin antibodies of IgM [6] and IgG isotype [7]. Altogether these are interesting data due to the interconnectedness of some vascular manifestation of SSc and the pathogenicity of aPL. Lipid peroxidation is the process through which arachidonic acid present in cell membranes and low-density lipoproteins transforms into cyclic compounds via a free radical process independent of cyclo-oxygenase. Of these cyclic compounds, 8-epiprostaglandin-F2alpha (8-epi-PGF2α) appears to be one of the most powerful vaso-active molecules existing [8] and is able to stimulate endothelin-1 (ET-1) production in pulmonary vascular cells [9]. Over-generation of 8-epiPGF2α has been found in SSc [10–13] particularly in relation to PAH [12] the pathogenesis of which in SSc is strongly dependent on ET-1 [14]. The same vaso-active compounds are implicated in the pathogenesis of the antiphospholipid syndrome: aPL induces endothelial cell production of ET-1 the serum level of which was particularly elevated in patients with arterial disease [15] whereas elevated serum 8-epi-PGF2α correlated to the titre of IgG aCL and to diastolic blood pressure [16]. Therefore SSc and APS share some pathogenetic pathways or putting it differently the pathogenicity of aPL adds to that of SSc worsening some clinical manifestations of the latter. However, the average serum level of aCL of the current and previous articles [3–5] are below the cut-off required for the diagnosis of APS Miyakis and very few of the SSc patients in these studies had thrombosis or miscarriages [3–7] though clinical overlaps may occur [17]. This leads to two important issues related to the significance of low titre aCL and to the treatment of SSc. With regards to the first issue are low titres aCL pathogenetic or not? Leaving aside the concepts of affinity and avidity of individual aPL, these SSc/aPL studies imply that on an appropriate oxidative background low titre aPL may worsen some vascular clinical manifestations through enhanced lipid peroxidation and ET-1 production. In a similar fashion, primary APS patients who also had elevated plasma homocysteine (that associates with increased lipid peroxidation) developed thrombosis at an earlier age than those primary APS patients who had normal plasma homocysteine: the average plasma IgG aCL of the former APS patients was lower than that of the latter [19]. The threshold of 40 GPL set by the expert committee relates to the occurrence of thrombosis and miscarriage to allow a diagnosis of APS [2] but should not necessarily Clin Rheumatol (2009) 28:881–882 DOI 10.1007/s10067-009-1210-3

Anticardiolipin Antibodies in HIV Infection Are Independently Associated with Antibodies to the Membrane Proximal External Region of gp41 and with Cell‐Associated HIV DNA and Immune Activation

The demonstration of in vitro cardiolipin reactivity with 2 human immunodeficiency virus (HIV)-specific, broadly neutralizing antibodies (2F5 and 4E10) has prompted reevaluation of autoimmune manifestations in HIV infection. We evaluated autoantibodies, particularly anticardiolipin (aCL), in 67 untreated, asymptomatic, HIV-infected individuals with slow progression of HIV disease and their correlation with 2F5-, 4E10-, b12-, and 2G12-like antibodies directed against epitopes involved in broad neutralization, as well as their correlation with immune activation and virological and clinical indicators. Fifty individuals with chronic HIV infection and standard disease progression were control patients. The majority of the study patients with slow progression of HIV disease were men (78%); their median age was 37 years, their median CD4+ cell count was 672 cells/mL, and their median plasma HIV load was 6200 copies/mL. The majority of the control patients were also men (76%), and most (62%) were receiving highly active antiretroviral therapy; their median age was 43 years, their median CD4+ cell count was 202 cells/mL, and their median plasma HIV load was 2265 copies/mL. aCL immunoglobulin G was detected at similar levels in 49% of patients with slow progression of HIV disease and in 58% of control patients. Viral load was positively associated with aCL in both groups (P < .001), independent of CD4+ cell counts. In patients with slow progression of HIV disease, aCL levels were also correlated with plasma HIV load and cell-associated DNA level (r = 0.486 and r = 0.516, respectively; P < .001), with the proportion of activated CD4+ cells, human leukocyte antigen-DR+ cells (r = 0.445; P = or < .001) but not activated CD8+ T cells, and with the level of B cell activation (quantified by soluble CD23; r = 0.354; P = .007). The level of aCL antibodies was associated with the level of antibodies to the membrane proximal region of gp41 (P = .003). aCL is frequently detected in HIV-infected patients, regardless of disease stage, and is strongly linked with the level of viral replication, the level of CD4+ T and B cell activation, and the level of antibodies to the membrane proximal external region of gp41, independent of CD4+ cell deficiency.

Antiphospholipid antibodies in young Indian patients with stroke

Stroke may be caused by antiphospholipid antibodies (APL), especially in young persons without other risk factors. The aim of this study was to determine the prevalence of two clinically significant APL-anticardiolipin antibody (ACL) and lupus anticoagulants (LA) in young patients presenting with sudden neurological deficit. A case-control study performed in a large tertiary care government hospital. Ten milliliters of blood was collected from 51 consecutive young patients (age less than 45 years) diagnosed as ischemic stroke and 50 healthy age- and sex-matched controls. Statistical analysis was done using Epi Info (TM) 6 software. Overall, the risk factor profile was: Smoking (23.5%), positive family history (13.7%), hyperlipidemia (8%), and diabetes mellitus (3.6%). APL (LA and ACL) were present in 29.4% of the samples and in 4% of controls. The 'P' value for ACL and LA was 0.03 and 0.02 respectively, but the maximum level of ACL was 25 GPL units only. One-fourth of the patients were smokers and one-sixth had a family history of thrombosis ( P = 0.048 and 0.036, respectively). APL, positive family history and smoking were significantly associated with stroke in the young. We advocate screening for APL in all young patients with stroke.

Performance of a New Global Chromogenic Assay for Protein C Pathway (HemosIL ThromboPath) in the Diagnosis of Lupus Anticoagulant and Antiphospholipid Antibodies.

Background: The HemosIL ThromboPath assay (Instrumentation Laboratory) is a new chromogenic assay designed to globally evaluate the functionality of the PC pathway. It is based on the ability of endogenous APC generated after activation of PC by a snake venom extract (Protac) to reduce the thrombin generation induced by a reagent containing tissue factor. Briefly, optical density is measured after addition of a thrombin-specific chromogenic substrate in the presence (OD A) or absence (OD B) of Protac. It is recommended by the test manufacturer to express results as the Protac-Induced Coagulation Inhibition percentage (PICI%) which corresponds to the ratio [OD B - OD A]/OD B x 100. Previous studies demonstrated a high sensitivity (over 96%) for PC pathway abnormalities i.e. PC/PS deficiency, and FV Leiden-related APC Resistance, but also for lupus anticoagulant (LA), known to be associated with acquired APC Resistance.The aim of the present study was to evaluate the sensitivity of that assay for antiphospholipid antibodies (APL), especially in connection with the occurrence of thrombotic complications. Actually, APL is a heterogeneous family of antibodies which have a significant impact on coagulation tests (LA) or could be detected using ELISA anticardiolipin assays (ACL).Methods: We retrospectively evaluated the frozen plasma samples from 178 patients previously diagnosed as positive for LA or as having high ACL levels. There were 48 M and 130 F with a mean age=43 years (range 14 – 87). None was on vitamin K-antagonist. Screening for LA, performed according to the ISTH criteria (Thromb Haemost 1995; 74:1185), was positive in 126 patients (LA+ patients) and negative in 52 patients, all of the latter having high ACL levels (LA- patients). Among LA+ patients, 41 had antiphospholipid syndrome (APS) i.e. 18 with a history of venous thrombosis (VT), 10 with arterial thrombosis (AT), 7 with obstetrical complication (OB) and 6 with combined vascular complications (CVC). The same applied to 39 LA- patients with high APL levels i.e. VT (n=13), AT (n=8), OB (n=12) and CVC (n=6). The control group consisted of 29 age- and sex-matched healthy subjects without a history of vascular or auto-immune disease. The HemosIL ThromboPath assay was performed by an operator blinded of the specific biological test results and of the clinical status of the patients.Results: Test result was significantly lower in LA+ patients than in LA- patients or in healthy controls (Table). Similarly, the percentage of abnormal test results i.e. PICI% below 85.0% as the cut-off value, was significantly higher in LA+ patients than in the two other groups (p<0.0001 in both cases). That cut-off value for the PICI% was determined, according to the recommendations of the reagent manufacturer, as the mean minus 1 SD of the values measured in the plasma of 29 healthy control subjects. Despite significantly lower PICI% in LA- patients than in controls (p<0.05), the proportion of abnormal test results was not significantly different (p<0.10) in these two groups.LA+ Patients (n=126)LA-Patients (n=52)Controls (n=29)Test Result (PICI%)74.5 ± 13.186.7 ± 9.490.3 ± 5.3PICI%<85% (n, %)99 (78.6%)15 (28.8%)3 (10.3%)Moreover, test result was not significantly different in LA+ patients with and without a history of vascular thrombosis (PICI%=74.4 ± 12.9, n=51 vs. 74.5 ± 13.5 n=75, p=0.91) and the same applied for the percentage of abnormal test results (n=41/51 (80.4%) vs. n=58/75 (77.3%); p=0.83). There was no significant difference between LA+ patients with venous, arterial thrombosis and obstetrical complications.Conclusion: The HemosIL ThromboPath assay was highly sensitive for LA (78.6%) but it did not allow to distinguish between LA+ patients those with APS. It was found to be weakly sensitive (28.8%) to high ACL levels without LA activity, despite a higher percentage of abnormal test results. The potential interest of the HemosIL ThromboPath assay as part of the screening strategy of LA deserves to be further investigated prospectively.

Higher serum clozapine level is associated with increased antiphospholipid antibodies in schizophrenia patients

Objectives This study was to evaluate the relationship between clozapine and aPL in schizophrenia patients. Methods 163 Participants were evaluated: 37 unmedicated schizophrenia patients, 50 clozapine-treated schizophrenia patients and 76 age- and sex-matched healthy controls. A fasting blood sample was taken for serum aPL and serum clozapine level. Serum aPL were measured by ELISA technique and HPLC method was used for the determination of serum clozapine level. Results The unmedicated schizophrenia patients showed higher IgG aCL level [mean ± SD: 1.51 ± 0.81 and 1.25 ± 0.13 U, respectively ( t = 2.77, df=111, p<0.01)] and IgM aCL level [mean±SD: 1.53 ± 0.54. and 1.33 ± 0.15 U, respectively ( t = −2.98, df = 111, p < 0.01)] compared with the healthy controls. The comparison of the clozapine-treated schizophrenia patients and the healthy controls showed significant difference in IgG aCL level [mean ± SD: 1.74 ± 0.90 and 1.25 ± 0.13 U, respectively ( t = −4.77, df = 124, p < 0.01)] and IgM aCL level [mean ± SD: 1.62 ± 0.83 and1.33 ± 0.15 U, respectively ( t = −4.35, df = 124, p < 0.01)]. In clozapine-treated schizophrenia patients, the results of Pearson correlation coefficients showed that there was a significant positive relationship between serum IgM aCL and serum clozapine level ( r = 0.461, p < 0.01), and serum IgG aCL were significantly correlated with serum IgM aCL (r = 0.279, p < 0.05). Stepwise multiple regression analysis was performed with various characteristics, such as duration of medication, daily dose and serum clozapine level as candidate factors for serum aCL (IgG and IgM isotypes) in clozapine-treated schizophrenia patients. Only serum clozapine level was able to enter into the regression model of IgM aCL (Model R 2 = 0.212, p < 0.05). Conclusions A higher serum clozapine level is associated with an increased aPL in schizophrenia patients.

Risk factors for a first thrombotic event in antiphospholipid antibody carriers. A multicentre, retrospective follow-up study

Objectives:To asses risk factors for a first thrombotic event in antiphospholipid antibody (aPL) positive carriers and evaluate the efficacy of prophylactic treatments.Methods:Recruitment criteria were age 18–65 years, no history of...

Antiphospholipid antibodies in adults with immune thrombocytopenic purpura

To determine the clinical significance of antiphospholipid antibodies (aPL) in patients with immune thrombocytopenic purpura (ITP), anticardiolipin (aCL) (IgG and IgM) and lupus anticoagulant (LA) were sought at diagnosis in 215 ITP adults with platelets <50 x 10(9)/l. aPL (aCL and/or LA) were detected in 55 patients (26%): aCL alone in 39 (18%), aCL and LA in 15 (7%) and LA alone in one (0.5%). LA was significantly associated with high IgG-aCL levels (P = 0.001). Among age, sex, initial platelet count, bleeding score, acute or chronic ITP outcome, only younger age was significantly associated with LA-positivity (mean age 29 +/- 14 years vs. 45 +/- 20 years, P = 0.002). After a median follow-up of 31 months, 14/215 (7%) patients developed thrombosis (four arterial, 10 venous and/or pulmonary embolism); four of them (29%) had high aCL levels and LA. Multivariate analysis significantly associated thrombosis events only with age [hazard ratio (HR) = 1.6; 95% confidence interval (CI): 1.2-2.4], LA (HR: 9.9; 95% CI: 2.3-43.4) or high IgG-aCL level (HR: 7.5; 95% CI; 1.8-31.5). Although the thrombosis rate was low, the significant associations between thrombosis and LA or high aCL level suggest that aPL should be tested at ITP diagnosis.

Early onset of autoimmunity in MRL/++ mice following immunization with beta 2 glycoprotein I.

Antiphospholipid antibodies (aPL) are associated with thrombosis, thrombocytopenia and recurrent fetal loss in humans and in some animal models. Immunization with beta 2 glycoprotein I (beta 2GPI) induced aPL production in normal rabbits and mice. However, the association of these antibodies with disease manifestations remains controversial. To determine whether induction of aPL by beta 2GPI immunization in an autoimmune strain of mice (MRL/++) would result in acceleration of clinical and serological autoimmune disease manifestations, three groups of 8-week-old female mice were studied. One group was immunized with beta 2GPI, and one with ovalbumin (OVA); the third was not immunized. After two booster injections, sera were analysed for the presence of anticardiolipin (aCL) and anti-DNA by ELISA and anti-nuclear antibody (ANA) by immunofluorescence. Mice were studied for thrombocytopenia, proteinuria, fecundity rates, litter sizes and the development of central nervous system dysfunction. Elevated levels of aCL, anti-DNA and ANA were detected in all beta 2GPI-immunized, in three OVA-immunized, and in none of the unimmunized mice. The anti-DNA antibodies were inhibited by CL micelles, suggesting cross-reactivity between aCL and anti-DNA. Platelet counts, fecundity rates and litter size were reduced in beta 2GPI-immunized but not in OVA-immunized or unimmunized mice. None of the mice developed neurological dysfunction or significant proteinuria over a 10-week period post-immunization. These findings suggest that beta 2GPI immunization induces aPL in MRL/++ mice associated with accelerated autoimmune manifestations resembling the antiphospholipid syndrome.

A protocol for determination of anticardiolipin antibodies by ELISA

The anticardiolipin (aCL) test has been widely used by physicians since the mid-1980s for diagnosing patients with antiphospholipid syndrome (APS). Establishment of this diagnosis has enabled effective management of patients with recurrent thrombosis or recurrent pregnancy losses. The test was first established in 1983 as a radioimmunoassay and soon thereafter converted into ELISA. There have been numerous efforts to standardize the aCL test, but precise reproducible measurement of aCL levels is difficult and the use of semiquantitative measurements (high, medium and low) is recommended as this is probably sufficient for clinical diagnosis. Using validated ELISAs for measuring aCL Abs offers greater reproducibility, would reduce interlaboratory variations and limit discrepancies in results between different laboratories. This article details a procedure that takes approximately 2 h and summarizes the information available on the aCL ELISA test.

High titer of serum antiphospholipid antibody levels in adult Henoch‐Schönlein purpura and cutaneous leukocytoclastic angiitis

To investigate a possible role of antiphospholipid (aPL) antibodies in adult Henoch-Schönlein purpura (HSP) and cutaneous leukocytoclastic angiitis (CLA). We reviewed the records of 30 HSP and 8 CLA adults with an initial cutaneous manifestation of palpable purpura on their lower extremities between 2003 and 2007. Eight microscopic polyangiitis (MPA) patients and 30 healthy persons were recruited as controls. Serum anticardiolipin (aCL), anti-phosphatidylserine-prothrombin complex (anti-PS/PT), and anti-beta(2)-glycoprotein I (anti-beta(2)GPI) antibody levels in HSP, CLA, MPA patients, and healthy controls were measured by enzyme-linked immunosorbent assay. Twenty-two HSP patients (73%) were positive for serum IgA aCL antibodies. Nineteen (63%) had IgA anti-PS/PT antibodies and 4 (13%) had IgA anti-beta(2)GPI antibodies. IgA aCL and anti-PS/PT antibodies showed a significant correlation (P = 0.007). Twenty (67%) HSP patients had IgM anti-PS/PT antibodies and 6 (20%) had IgG anti-PS/PT antibodies. Six (75%) CLA patients had IgM anti-PS/PT antibodies and 2 (25%) had IgG anti-PS/PT antibodies. In contrast, aPL antibodies were not found in any MPA patients or normal controls. Serum IgA aCL antibody levels in HSP patients showed a significant correlation with serum IgA and C-reactive protein (CRP) levels (P = 0.030 and 0.039, respectively). A positive correlation between CRP and serum IgA anti-PS/PT antibody levels was observed in HSP patients (P = 0.023). Serum IgA aCL antibody levels were also significantly associated with proteinuria according to urinalysis (P = 0.024). Serum levels of IgA aCL and anti-PS/PT antibodies were elevated in adult HSP, suggesting that serum IgA antibodies may play some role in adult HSP. IgA aCL and/or anti-PS/PT antibodies could serve as markers for adult HSP and should be monitored as an indicator of adult HSP activity. Small-vessel vasculitis could be dependently associated with the presence of IgM anti-PS/PT antibodies. These findings suggest that aPL antibodies are closely related to the pathogenic factors that trigger the development of vasculitis.

Anti-Cardiolipin Antibodies and Endothelial Function in Patients With Coronary Artery Disease

Endothelial dysfunction is considered an important marker in atherosclerosis, having a prognostic value. Antiphospholipid antibodies are considered prothrombotic and have recently been reported to be associated also with atherosclerosis. This study was conducted to investigate a possible association of endothelial dysfunction with various antiphospholipid autoantibodies in healthy subjects and patients with cardiovascular disease. In a single-center, prospective study, 2 groups were included. The study group included patients with cardiovascular diseases (coronary disease and/or cerebrovascular disease) and healthy subjects without apparent heart disease who were referred to the endothelial function laboratory for the assessment of endothelial function. Flow-mediated dilatation, which indicates endothelial function, and nitroglycerin-mediated vasodilatation, which indicates smooth-muscle function, were measured. The 2 groups were evaluated for autoantibodies, including anticardiolipin (aCL; immunoglobulin G [IgG], immunoglobulin M [IgM], and immunoglobulin A [IgA]), antinuclear antibody, anti-beta2-glycoprotein I (IgG, IgM, and IgA), and oxidized low-density lipoprotein. One hundred seven subjects were included in the study: 45 patients (42%) and 62 healthy controls (58%). Flow-mediated dilatation was significantly lower in patients compared with healthy controls (8.0 +/- 9.5% vs 8.0 +/- 13.5%, p = 0.012). In addition, nitroglycerin-mediated vasodilatation was nonsignificantly lower in patients than in healthy controls (8.0 +/- 13.4% vs 11.0 +/- 16.7%, p = 0.084). The mean levels of anti-beta2-glycoprotein I (IgG, IgM, and IgA), aCL (IgM and IgA), antinuclear antibody, and oxidized low-density lipoprotein were not different between groups. However, the mean level of IgG aCL was significantly higher in patients than in healthy controls. In conclusion, in accordance with previous reports of an association between aCL and atherosclerosis, patients with cardiovascular disease had endothelial dysfunction and elevated levels of aCL.

Are the Anticardiolipin Antibodies a Risk Factor for Coronary Artery Disease in Chronic Renal Failure Patients?

Objective. It has been proposed that anticardiolipin (aCL) antibodies are a risk factor for coronary artery disease (CAD) in recently studies. In this study, we aimed to investigate the existence of coronary artery disease in dialysis patients who were aCL positive and undergoing hemodialysis and peritoneal dialysis due to end stage renal failure and also to determine its relationship with risk factors in patients with coronary artery disease. Methods. This study has been conducted in the end stage renal failure in 140 hemodialysis patients, 18 peritoneal dialysis patients, and 38 healthy controls. The urea, creatinine, total cholesterol, HDL cholesterol, LDL cholesterol, triglyceride, total protein, and albumin values are obtained. In all cases, aCL levels are investigated with ELISA method. Results. In the HD and CAPD patients, no significant relationship could be found between the age, gender, dialysis time, total cholesterol, HDL cholesterol, LDL cholesterol, total protein, and albumin values (p > 0.05). HD and CAPD vs. controls (aCL), 9.2% (13/140), 11.1% (2/18) vs. 2.6% (1/38), p = 0.002. No significant difference was noted between aCL-positive and -negative patients in serum urea, creatinine, total cholesterol, HDL cholesterol, LDL cholesterol, triglyceride, total protein, and albumin levels. The coronary artery disease was determined in three patients out of 16 patients with aCL positivity. Conclusion. The prevalence of aCL antibodies positivity in our study was similar to the prevalence of aCL positivity in other studies. Therefore, we do not think aCL antibodies positivity is a risk factor for coronary artery disease.

Anti-β2-glycoprotein I in childhood immune thrombocytopenic purpura

Immune thrombocytopenic purpura (ITP) etiology is not clarified. Phospholipid antigen antibodies (aPls) occur in ITP patient sera. We studied predictive values of elevated anti-beta2-glycoprotein I (anti-beta2-GP1) or anticardiolipin antibody (aCl) concentrations for secondary ITP detection, comparing levels with steroid therapy responsiveness in three groups of children and adolescents. Participants' antinuclear antibodies, aCls (IgM, IgG) and anti-beta2-GPI (IgG) were assessed. Significantly higher aCl (IgM), aCl (IgG) and anti-beta2-GPI (IgG) mean concentrations occurred in chronic ITP cases compared with acute or control cases. Of chronic ITP cases, 77.8% showed elevated IgG aCl serum concentrations, and all presented increased IgG anti-beta2-GPI serum levels. Significant positive correlation between increased levels of IgG anti-beta2-GPI and increased IgG aCl serum concentrations was determined; these increased IgG concentrations significantly correlated with steroid therapy resistance. A total of 76.1% of ITP cases had positive aPls (all chronic ITP cases, five acute ITP cases). Elevated aCl or anti-beta2-GPI serum IgG isotype concentrations occurred in all nine splenectomized ITP children with positive aPls (three showed increased IgM aCl levels). Follow-up of the initially studied ITP children (2000-2004) revealed 16.7% developed clinical and laboratory criteria of systemic lupus erythrematosus (one acute ITP in remission, six chronic ITP); elevated IgG aCl serum concentrations were found at study start in these seven cases, and six had increased anti-beta2-GPI. IgG classes of both aCls and anti-beta2-GPI may be determinant cofactors for the developing risk of antiphospholipid syndrome or autoimmune diseases in ITP. Great attention should be paid to both assays as predictors for steroid therapy response.