Avidity of selected autoantibodies - usefulness of their determination for clinical purposes.

Autoantibodies directed against various self-antigens comprise a heterogeneous group of immunoglobulins, which differ in their qualitative and quantitative features. An important qualitative characteristic of antibodies is affinity/avidity, which changes in the process of its maturation during the immune response.This study is aimed to summarize the knowledge about avidity of selected autoantibodies in certain autoimmune diseases. The avidity of various autoantibodies differs under distinct clinical situations. High-, moderate or low-avidity may be found in biological fluids in patients with autoimmune diseases.The avidity maturation associated with progression from low to high values typical for antibodies against exogenous antigens is not always uniform in autoimmune diseases; therefore, the avidity of each autoantibody should be judged individually. Some studies promise the possible benefit of avidity examination for the refinement of diagnosis and prediction of selected autoimmune diseases.Key words: affinity - anti-citrullinated protein antibodies - anti-glomerular basement membrane antibodies - anti-glutamate decarboxylase antibodies - anti-insulin antibodies - autoantibodies - avidity - onconeuronal antibodies.

Avidity of antiphospholipid antibodies - our current knowledge.

Antiphospholipid antibodies (APL), which represent serum markers of the antiphospholipid syndrome, comprise an extremely heterogeneous group of autoantibodies directed against various phospholipids and protein cofactors. The heterogeneity of APL includes not only their antigen-binding site specificity but also their avidity. The aim of this study was to summarize the current knowledge about commonly-used procedures for the avidity determination with a special interest in the antiphospholipid antibodies and to evaluate the clinical significance of APL avidity determination. The common techniques in clinical laboratories for avidity determination utilize the ELISAs in the presence of various chaotropic agents. The findings of clinical studies suggest that the high avidity APL are associated with thrombosis and antiphospholipid syndrom (APS). The determination of APL avidity might be a complementary laboratory marker applicable in the classification of APS.

Cerebrospinal fluid and serum antibodies against neurofilaments in patients with amyotrophic lateral sclerosis.

BACKGROUND: The aim of the study was to assess autoimmune involvement in amyotrophic lateral sclerosis (ALS). METHODS: We measured IgG antibodies against light (NFL) and medium (NFM) subunits of neurofilaments using ELISA in paired cerebrospinal fluid (CSF) and serum samples from 38 ALS patients and 20 controls. RESULTS: Serum levels of anti-NFL were higher in ALS patients than in controls (P < 0.005). Serum anti-NFL antibodies and intrathecal anti-NFM antibodies were related to patient disability (serum anti-NFL: P < 0.05; intrathecal anti-NFM: P < 0.05). Anti-NFL levels were significantly correlated with anti-NFM levels in ALS (P < 0.001) and the control group (P < 0.0001) in the CSF, but not in serum. Anti-NFL and anti-NFM antibodies significantly correlated between serum and CSF in the ALS group (anti-NFL: P < 0.0001; anti-NFM: P < 0.001) and in the control group (anti-NFL: P < 0.05; anti-NFM: P < 0.05). CONCLUSIONS: Autoimmune humoral response to neurocytoskeletal proteins is associated with ALS.

Relationship between ALS and the degree of cognitive impairment, markers of neurodegeneration and predictors for poor outcome. A prospective study.

INTRODUCTION: Amyotrophic lateral sclerosis (ALS) is a common neurodegenerative disease affecting motor neurons and may be associated with impaired cognition. Reliable prognostic factors for ALS patients are still missing. METHODS: We prospectively included 67 patients, 42 women and 25 men, with clinically defined ALS. The disease severity was assessed and the patients underwent SPECT, lumbar puncture with determination of tau, hyperphosporylated tau (p-tau) and beta-amyloid and a detailed neuropsychological assessment using a standardized test battery. In patients who died, a detailed neuropathologic evaluation was performed. RESULTS: The mean survival duration was 26.8 months. The delay between the first signs and confirmation of the diagnosis was 12.75 months. Cognitive impairment did not have an impact on the evolution of the disease. There was no correlation between neuropsychological and SPECT findings. Higher age at onset, more pronounced handicap and elevated beta-amyloid in the CSF were associated with shorter survival times. In brain tissue from nine of the deceased patients with ALS and dementia, all showed signs of comorbidity, six had hallmarks of frontotemporal lobar degeneration (FTLD) and three showed Alzheimer disease pathology. Brain tissues form 11 deceased ALS patients who did not show signs of dementia, had only changes compatible with a diagnosis of motor neuron disease. CONCLUSION: In our prospective study, age, disease severity and CSF beta-amyloid levels taken together were a risk factor suggesting shorter survival times. Dementia is relatively frequent in ALS and may be a consequence of either FTLD or result from co-existing Alzheimer disease.

Synergy of serum and cerebrospinal fluid antibodies against axonal cytoskeletal proteins in patients with different neurological diseases.

Autoantibodies against different axonal cytoskeletal proteins [the light (NFL) and medium (NFM) subunit of neurofilament and tubulin (TUB)] in serum and cerebrospinal fluid may be generated in response to the release of cytoskeleton from damaged neurons. We studied the relationships among these autoantibodies. Paired cerebrospinal fluid (CSF) and serum samples were obtained from 47 multiple sclerosis (MS) patients, 14 patients with neurodegenerative diseases, 21 patients with various neurological diseases and 16 normal control subjects. Levels of antibodies against NFL, NFM and TUB were related to each other in CSF in all groups, whereas close association of anti-cytoskeletal antibodies in serum was found in the MS group only. A concordant spectrum of anti-cytoskeletal antibodies is present in serum of MS patients, unlike in other neurological patients. The synergy between the spectrum of anti-cytoskeletal antibodies in serum and CSF might be one of the immunological features typical for the MS patients.

AADvac1, an Active Immunotherapy for Alzheimer's Disease and Non Alzheimer Tauopathies: An Overview of Preclinical and Clinical Development.

Neurofibrillary tau protein pathology is closely associated with the progression and phenotype of cognitive decline in Alzheimer's disease and other tauopathies, and a high-priority target for disease-modifying therapies. Herein, we provide an overview of the development of AADvac1, an active immunotherapy against tau pathology, and tau epitopes that are potential targets for immunotherapy. The vaccine leads to the production of antibodies that target conformational epitopes in the microtubule-binding region of tau, with the aim to prevent tau aggregation and spreading of pathology, and promote tau clearance. The therapeutic potential of the vaccine was evaluated in transgenic rats and mice expressing truncated, non mutant tau protein, which faithfully replicate of human tau pathology. Treatment with AADvac1 resulted in reduction of neurofibrillary pathology and insoluble tau in their brains, and amelioration of their deleterious phenotype. The vaccine was highly immunogenic in humans, inducing production of IgG antibodies against the tau peptide in 29/30 treated elderly patients with mild-to-moderate Alzheimer's. These antibodies were able to recognise insoluble tau proteins in Alzheimer patients' brains. Treatment with AADvac1 proved to be remarkably safe, with injection site reactions being the only adverse event tied to treatment. AADvac1 is currently being investigated in a phase 2 study in Alzheimer's disease, and a phase 1 study in non-fluent primary progressive aphasia, a neurodegenerative disorder with a high tau pathology component.

Cerebrospinal fluid antibodies to tubulin are elevated in the patients with multiple sclerosis.

BACKGROUND AND PURPOSE: The aim of this study was to compare the levels of anti-tubulin antibodies (anti-TU) in cerebrospinal fluid (CSF) and serum using bovine tubulin as the antigen in one enzyme-linked immunosorbent assay (ELISA) method (anti-TUb antibodies) and a synthetic neuron-specific octapeptide of tubulin in a second ELISA method (anti-TUs antibodies). METHODS: Paired CSF and serum samples were obtained from 34 multiple sclerosis (MS) patients, 13 patients with various other neurological diseases (control diseases) and 17 normal control patients (CN). RESULTS: CSF levels of anti-TUs and anti-TUb antibodies were significantly lower in the CN group when compared to those in the MS group. On the contrary, serum levels of anti-TU antibodies did not differ among groups. The intrathecal synthesis of anti-TUs antibodies in comparison with anti-TUb was significantly increased in all groups. Significant correlations between anti-TUb and anti-TUs antibodies were observed in the CSF of all three groups. However, with regard to serum, a similar relationship was only found in the MS group. CONCLUSIONS: The estimation of anti-TU in CSF can contribute to the overall assessment of axonal damage; on the contrary serum anti-tubulin antibodies were not useful for differential purposes in MS. The antibodies to the neuron-specific portion of tubulin seemed to be synthesised predominantly intrathecally.

Advanced oxidation protein products in obstructive sleep apnea.

Obstructive sleep apnea (OSA) is a risk factor of hypertension, coronary artery disease and stroke. OSA is also considered a cause of accelerated atherogenesis. Advanced oxidation protein products (AOPP) are among the biochemical indicators of higher risk of atherogenesis as an independent risk factor for coronary artery disease. 20 men suffering from OSA were examined using night polygraphy, the AOPP were determined from their morning blood samples. The mean AOPP concentration in the patients group was 91.8 (SD=42.3) micromol/l, in the control group 76.2 (SD=35.3) pmol/l, the difference was not significant. The AOPP were found correlated with the AHI (apnoe/hypopnoe index) (R=0.485, P=0.030). The results support the hypothesis that OSA increases the oxidative stress and atherogenesis.

Pregnancy-associated plasma protein-A in patients with cerebrovascular diseases--a pilot study.

Pregnancy-associated plasma protein-A (PAPP-A) was described as a novel marker of acute coronary syndrome. The aim of our study was to investigate how serum pregnancy-associated plasma protein-A (PAPP-A) levels change in patients with ischaemic stroke and intracerebral haemorrhage and to evaluate if PAPP-A might be a marker not only of myocardial infarction but also a useful parameter in cerebrovascular disorders. 43 patients with acute cerebrovascular events were divided into 3 groups--patients with ischaemic stroke (n=16), patients with intracranial haemorrhage (n=10) and patients with both ischaemic stroke and coronary artery disease (n=17). The control group consisted of 12 subjects. PAPP-A was measured by TRACE (Time Resolved Amplified Cryptate Emission) technology. PAPP-A levels in patients with intracranial haemorrhage and those with both ischaemic stroke and coronary artery disease were increased in comparison with the control group (p<0.005, p<0.01, respectively) as well as with patients with ischaemic stroke only (p<0.01, p<0.05, respectively). A positive correlation between PAPP-A and total cholesterol in patients with both ischaemic stroke and coronary artery disease (r=0.497, p<0.05) was observed. Serum PAPP-A levels in all studied patients correlated positively with serum creatinine (r=0.395, p<0.05). PAPP-A levels are increased in patients with intracranial haemorrhage and in the patients whose ischaemic stroke is associated with coronary artery disease. The atherosclerotic process may contribute to increased serum PAPP-A levels. PAPP-A may be a marker of increased risk of atherothrombotic events in general.

Antibodies against beta 2-glycoprotein I (beta 2-GP I) and their relationship to fetoplacental antigens.

Binding of beta 2-GP I to anionic phospholipids is thought to be the major antigen required in the reaction of anticardiolipin antibodies to phospholipids. The aim of this study was to investigate the changes of anti-beta 2-GP I IgG during the first and second trimester of pregnancy and the relationship between the levels of anti-beta 2-GP I and fetoplacental antigens and the correlation between anti-beta 2-GP I IgG and antibodies against oxidized low-density lipoprotein IgG (oLAb) in serum of pregnant women. We determined anticardiolipin antibodies (ACA) IgG and maternal serum levels of alpha 1-fetoprotein (AFP), human chorionic gonadotrophin (HCG) and trophoblast-specific beta 1-glycoprotein (SP1) in 204 pregnant women in the first and second trimester. From this group we selected 52 serum samples positive for ACA IgG and 16 samples negative for ACA IgG. In the samples of selected patients, the levels of anti-beta 2-GP I IgG and oLAb IgG were determined. Anti-beta 2-GP I IgG levels significantly decreased in the second trimester (6.2+/-9.3 U/ml, mean +/- S.D.) in comparison with the first trimester (8.3+/-10.4 U/ml) (p=0.05). Multiple of median (MoM) AFP correlated negatively but not significantly in the first trimester with anti-beta 2-GP I (r = -0.261, p = 0.12). In the second trimester this correlation was significantly negative (r = -0.278, p = 0.04). The Spearman correlation coefficients for MoM HCG and anti-beta 2-GP I were 0.158 for the first trimester and 0.174 for the second trimester. MoM SP1 also did not correlate significantly with anti-beta 2-GP I in both trimesters. The correlation between anti-beta 2-GP I IgG and oLAb IgG was not significant (r = -0.06). In the first trimester 40 % serum samples were positive for anti-beta 2-GP I IgG and negative for oLAb IgG or vice versa, while 60 % samples in the second trimester were positive only for one determined autoantibody. We can conclude that the levels of anti-beta 2-GP I IgG decrease during the second trimester probably as the result of the effects of some immunosuppressive agents associated with pregnancy. The finding of negative correlation between AFP and anti-beta 2-GP I suggests that anti-beta 2-GP I has an influence on fetus development.

Prevalence of various antiphospholipid antibodies in pregnant women.

Antiphospholipid antibodies (APAs) are characterized as a heterogeneous population of autoantibodies directed against different target antigens, predominantly anionic phospholipids or phospholipid-containing structures. The presence of APAs has been strongly associated with a variety of clinical disorders including adverse pregnancy complications such as spontaneous abortions, pregnancy-induced hypertension, preeclampsia and intrauterine growth retardation. The purpose of this study was to compare the prevalence of anticardiolipin antibodies (ACAs), which are routinely examined, with APAs directed against phosphatidylserine (APS), phosphatidylinositol (API), phosphatidylethanolamine (APE) and phosphatidylcholine (APC) in the sera of pregnant women. We examined 410 serum samples of pregnant women hospitalized in the department for pathological pregnancies. They underwent prenatal biochemical screening of fetal congenital abnormalities in the first and the second trimester of gravidity. Anticardiolipin IgG and IgM were measured using commercial ELISA kits (ImmuLisa Anti-Cardiolipin Antibody), whereas APS, APE, API and APC were determined by our modified ELISA kit. Among 410 pregnant women we found 21 patients (5.1%) positive for ACA IgG (>20 GPL) and 30 patients (7.3%) positive for ACA IgM (>10 MPL). It was found that 7.8% of pregnant women had at least one high-titer APA IgG and 9.8% high-titer APA IgM. One third of ACA IgG or IgM positive sera contained polyspecific autoantibodies reactive to at least two various phospholipids. In the group of IgG ACA positive women, 28.6% patients were positive for APS, 28.6% were positive or moderately positive for API, 23.8% for APC and 19% for APE. In the group of IgM ACA positive women, 33.3% were also positive for APS, 26.7% for APE, 26.7% for API and 23.3% for APC were present. IgG and IgM ACA negative patients exhibited a significantly lower incidence of other APA than the group of ACA positive pregnant women. It still remains to clarify if the routine examination of APA reacting with other anionic and zwitterionic antigens other than cardiolipin would improve the probability of identifying women liable to adverse pregnancy complications.

Antibodies against oxidized LDL--theory and clinical use.

Modification of low density lipoprotein (LDL) particles due to oxidation, glycation and binding of advanced glycation end-products (AGEs) or malondialdehyde (MDA, a final product of lipid peroxidation) is considered most important in the process of atherogenesis. Oxidatively modified LDL are distinguished by another receptor type, which was discovered on the surface of macrophages and was called the scavenger receptor. Uncontrolled intake of LDL converts macrophages to foam cells; their accumulation under the vascular endothelium is considered as the first stage of atherosclerosis. Oxidation of LDL is a complex process taking place in both the extra- and intracellular space. At the end of this oxidative process, modified LDL particles show chemotactic, cytotoxic and immunogenic properties. Oxidized LDL express a large number of epitopes and cause production of polyclonal autoantibodies against these products, especially against apoB100 modified by MDA and 4-hydroxynonenal. IgoxLDL (antibodies against oxidized LDL) can be demonstrated either directly in intimal lesions or as a component of circulating immune complexes. IgoxLDL do not form a homogeneous group but a varied mixture of antibodies-isoantibodies caused by HDL and LDL polymorphism, antibodies against the lipid phase of LDL and antibodies against modified apoB100 of the immunoglobulin class IgA or IgG. Antibodies against oxLDL were found in many diseases other than atherosclerosis such as diabetes mellitus, renovascular syndrome, uremia, rheumatic fever, morbus Bechtjerev or lupus erythematodes. Newborns have practically the same levels of IgoxLDL as their mothers; however, these values did not differ from those in the healthy population of non-pregnant women of the same age. The decrease in IgoxLDL titer was very slow and lasted many months; that is why this parameter cannot be considered suitable for describing the rapid changes during oxidative stress of the organism. Positive correlation of IgoxLDL with antiphospholipids and other antibodies was repeatedly demonstrated; their determination can thus be used as a marker for the description of total production of autoantibodies in various diseases. The changes and correlations of IgoxLDL, anti-beta-2-glycoprotein I IgG and antiphospholipid antibodies support the immunological link between thrombotic and atherosclerotic processes in the human body.

Antibodies against oxidized low density lipoproteins in pregnant women.

Oxidized low density lipoproteins (oxLDL) formed in vivo induce a humoral immune response. Oxidative modification of LDL renders it immunogenic and a heterogeneous population of specific anti-oxLDL antibodies is produced. These antibodies could represent a biological marker of oxidative stress and serve as markers of atherosclerosis. Autoantibodies against oxLDL (oLAb) have been detected in human subjects practically of every age. oLAb also appear in the blood of pregnant women. Some studies have shown that the levels of antibodies to oxLDL were elevated in women with established preeclampsia. The present study was aimed to estimate the oLAb IgG levels in the first and second trimester of pregnancy. Furthermore, we estimated the correlation between maternal serum (MS) levels of oLAb and alpha-1-fetoprotein (MS AFP), human chorionic gonadotrophin (MS HCG) and trophoblast-specific-beta-1-glycoprotein (MS SP1), because these proteins are determined as a part of prenatal biochemical screening for fetal congenital abnormalities. Our study deals with the oLAb changes in women with pregnancy-induced hypertension. We also investigated the correlation between oLAb IgG and anticardiolipin antibodies IgG (ACA) in the serum of pregnant women. We examined 40 pregnant women attending Institute for Mother and Child Care for their antenatal care as outpatients. Routine blood samplings between the 9-13th week of pregnancy and 16-18th week of pregnancy were performed as a part of biochemical prenatal screening for fetal congenital abnormalities (Group 1). Their mean age was 27 +/- 4.1 years. Furthermore, we examined 26 women in the second or third trimester with pregnancy-induced hypertension (Group 2). Group 2 was compared with 49 pregnant women in the second or third trimester who were normotensive (Group 3). We used commercial standardized ELISA kits for determination of oLAb IgG, ACA IgG, MS AFP and MS HCG, MS SP1 was analyzed by single radial immunodiffusion. We did not find any differences in the levels of oLAb IgG in the first and second trimester in the women of Group 1. The correlation between oLAb and ACA IgG was not statistically significant (Spearman coefficient r=0.22, p=0.1). The correlation between oLAb IgG with MS AFP, MS HCG and MS SP1 was not statistically significant. Weak negative correlation for AFP and HCG was suggested both in the first and in the second trimester. The levels of oLAb IgG in the group of women with pregnancy-induced hypertension were significantly lower than in the group of normotensive women (348 +/- 388 U/ml v.s. 579 +/- 400 mU/ml, p<0.01). We can conclude that the levels of oLAb do not differ in the first and second trimester of gravidity. However, we cannot exclude the possible influence of an inverse relationship between oLAb IgG titers and the synthesis of fetoplacental antigens. This finding is important especially in the context of the results of prenatal biochemical screening. Pregnancy-induced hypertension is associated with lower levels of oLAb. Weak cross-reactivity between oLAb and anticardiolipin antibodies may exist but there is a possibility that there are two different populations of antibodies reacting with various antigens.

Hyperlipoproteinemia impairs endothelium-dependent vasodilation.

Atherogenic lipoproteins can cause endothelial dysfunction in the initial stage of atherogenesis. In our study we examined 134 patients with defined hyperlipoproteinemia (non-HDL cholesterol>4.1 mmol/l or triglycerides>2.5 mmol/l or taking any of lipid lowering drugs)--94 men and 40 women. The subgroup of controls of comparable age contained 54 normolipidemic individuals--30 men and 24 women. Patients with hyperlipoproteinemia revealed significantly lower ability of endothelium-dependent flow-mediated vasodilation (EDV) measured on brachial artery (4.13+/-3.07 vs. 5.41+/-3.82 %; p=0.032) and higher carotid intima media thickness than normolipidemic controls (0.68+/-0.22 vs. 0.58+/-0.15 mm; p=0.005). In regression analysis, EDV correlated significantly with plasma concentrations of oxLDL (p<0.05) HDL-cholesterol (p<0.05), Apo A1 (p<0.05), ATI (p<0.01) and non-HDL cholesterol (p<0.05). Patients with hyperlipoproteinemia showed higher plasma levels of oxLDL (65.77+/-9.54 vs. 56.49+/-7.80 U/l; p=0.015), malondialdehyde (0.89+/-0.09 vs. 0.73+/-0.08 micromol/l; p=0.010) and nitrites/nitrates (20.42+/-4.88 vs. 16.37+/-4.44 micromol/l; p=0.018) indicating possible higher long-term oxidative stress in these patients.

Antibodies against phospholipids and oxidized LDL in alcoholic patients.

Antiphospholipid antibodies (APA) are a generic term describing antibodies that recognize various phospholipids. Hepatocyte damage is a cardinal event in the course of alcoholic liver injury and autoantibodies against phospholipids could play an important role in this process. APA in alcoholic patients seem to reflect membrane lesions, impairment of immunological reactivity, liver disease progression and they correlate significantly with disease severity. LDL oxidation is supposed to be one of the most important pathogenic mechanisms of atherosclerosis and antibodies against oxidized low-density lipoprotein (oxLDL) are some kind of an epiphenomenon of this process. The scope of our study was to determine some autoantibodies (IgG-oxLDL and antiphospholipid antibodies) and their possible changes in alcoholic patients. We studied IgG-oxLDL and four APA - anticardiolipin antibodies (ACA), antiphosphatidylserine antibodies (APSA) antiphosphatidylethanolamine antibodies (APE) and antiphosphatidylcholine antibodies (APCA) in 35 alcoholic patients with mildly affected liver function at the beginning of the abuse treatment. The control group consisted of 60 healthy blood donors. In the studied group, we obtained positive results concerning total ACA in 17.1 % of alcoholic patients (8.3 % in the control group), 11.4 % IgG-ACA (6.7 %), 8.6 % IgM-ACA (3.3 %), 14.3 % total APE (6.7 %), 14.3 % total APCA (8.3 %) and 20 % total APSA (8.3 % in the control group). The IgG-oxLDL (406.4+/-52.5 vs 499.9+/-52.5 mU/ml) was not affected in alcoholic patients. We conclude that the autoantibodies against oxLDL are present in sera of alcoholics and healthy blood donors. Based on our results which revealed a wide range of IgG-oxLDL titres in the healthy population, this parameter does not appear to be very promising for the evaluation of the risk of atherosclerosis. Alcoholics with only mild affection of liver functions did not exhibit a significantly higher prevalence of all studied antiphospholipid antibodies (ACA, APSA, APE, APCA) which could lead to membrane lesions in these patients.

Pregnancy-associated plasma protein A during hemodialysis with polyamide and diacetate cellulosic membranes.

Pregnancy-associated plasma protein A (PAPP-A) is a new prognostic factor of acute coronary syndrome in the general population. It is elevated in hemodialysis (HD) patients and at baseline, it was shown to be related to inflammation and oxidative stress. The aim of the study was to examine the relationship of PAPP-A and oxidative stress and inflammatory markers to HD treatment. Studied parameters were determined in 10 chronic HD patients treated with low flux polyamide (1st session) and diacetate cellulosic membranes (2nd session) at the beginning, after 15 minutes and at the end of the dialysis session. TRACE method (Time Resolved Amplified Cryptate Emission) was used for PAPP-A assessment. Results were evaluated with ANOVA. PAPP-A levels did not depend on the type of HD membrane but changed significantly with the time of the HD session. They increased significantly from the beginning of HD to 15 min and then decreased to the end of the HD session - p<0.05 15 min of HD vs start, p<0.01 end vs start, p<0.0001 end vs 15 min of HD for polyamide membrane and p=0.05 15 min of HD vs start, p<0.01 end vs start, p<0.0001 end vs 15 min of HD for diacetate cellulosic membrane. Changes in other parameters and differences between membranes were only minimal. We can conclude that PAPP-A as a marker of cardiovascular damage shows significant changes during the HD session. Its initial increase might be ascribed to its release from complexes or storage. During dialysis, it might be destroyed or cleaved and removed as free fragments. Its levels both before and after the HD session are higher than in healthy subjects.

[ELISA in the determination of antiphosphatidylserine antibodies]. / Metoda ELISA pro stanovení antifosfatidylserinových protilátek.

Antiphospholipid antibodies (APA) are a group of antibodies against various phospholipid antigens. In order to extend the spectrum of examined specificities of antiphospholipid antibodies the authors elaborated an ELISA method for assessment of antiphosphatidyl serine antibodies (APSA). As antigen they used phosphatidyl serine isolated from the white matter of cattle brain. The ELISA method was tested by examining APSA in 12 patients with rheumatic diseases, 24 women with reproductive disorders and 50 patients with testicular tumours and the results were compared with examinations of anticardiolipin antibodies. The concurrent presence of both types of antibodies was recorded in 20.8% women with reproductive disorders and in 14% of the patients with testicular tumours. In these groups antiphosphatidyl serine antibodies were found more frequently.

[Determination of antiphospholipid antibodies in serum using ELISA]. / Stanovení antifosfolipidových protilátek v séru metodami ELISA.

The authors compare two ELISA methods for the assessment of antiphospholipid antibodies, classes IgG and IgM, in serum: ELISA Pin Plate System ALPHA DIALAB Co. and the ELISA method developed in the Research Institute of Rheumatic Diseases. Both methods use cardiolipin as antigen. In the Pin Plate test the immunochemical reaction antigen/antibody does not take place at the surface of the pits of the microtitration plates but on the tip of the next plate. The results of examinations of antiphospholipid antibodies obtained by the tested methods are comparable, the Pin Plate test is quicker and more sensitive, but its price limits routine use.

[Antiphospholipid antibodies in women with reproductive disorders]. / Antifosfolipidové protilátky u zen s nekterými poruchami reprodukce.

The authors examined in serum of 121 women, using the ELISA method, anticardiolipine antibodies (ACA) class IgG and IgM. The examined women were divided into a group of women with a normal pregnancy (n = 14), a group of women with imminent abortion during the first trimester (n = 10) and a group of women treated for prolonged periods on account of sterility (n = 97). In women with a normal pregnancy only in one a positive titre in the IgG class was recorded. In the group with imminent abortion a positive ACA titre was found in three patients (30%); in women with negative results of the ACA examination, pregnancy continued. In sterile women positive ACA tests were recorded in 14.5%.

[Comparative study of the occurrence of beta-2-glycoprotein I antibodies (anti-beta-2-GPI) and anticardiolipin antibodies (ACA) in the blood of pregnant women]. / Srovnávací studie výskytu protilátek proti beta-2-glykoproteinu I (anti-beta-2-GPI) a antikardiolipinových protilátek (ACA) v séru tehotných zen.

OBJECTIVE: It is accepted now that most antiphospholipid antibodies (APA) are not directed against phospholipids alone but complexes of phospholipid-binding proteins and phospholipids. One of the phospholipid-binding proteins is beta 2-glycoprotein I (beta 2-GPI), a normal plasma glycoprotein, which under physiological conditions binds with negative charged phospholipids. Measurement of anti-beta 2-GPI antibodies requires specific tests, since ELISA for determination of anticardiolipin antibodies (ACA) may detect both antibodies directly binding cardiolipin and antibodies against cardiolipin-binding proteins. In this study a comparison of APAs against cardiolipin (CL), phosphatidylserine (PS), phosphatidylinositol (PI), phosphatidylethanolamine (PE) v.s. anti-beta 2-GPI were compared. SETTING: First Institute of Medical Chemistry and Biochemistry, First Medical Faculty, Charles University and Institute for Care of Mother and Child. DESIGN: Retrospective clinical study using stored sera for determination of APA. METHODS: One hundred twenty four women in the first and the second trimester, who undergo biochemical prenatal screening for chromosomal disorders by maternal serum alpha-fetoprotein (MS AFP), human chorionic gonadotrophin (MS HCG) and trophoblast-specific beta 1-glycoprotein (MS SP1) were studied. In serum samples antibodies against CL, PS, PE, PI (isotype IgG and IgM) were examined by solid ELISA. 19 women who were positive at least for one type of APAs were selected and in the serum samples the levels of anti-beta 2-GPI were measured. RESULTS: No pregnant woman with anti-beta 2-GPI had positive antibodies against other phospholipids except CL. There was no significant correlation between levels of ACA IgG and IgM v.s. anti-beta 2-GPI IgG and IgM. Eight percent of serum samples were positive for both anti-beta 2-GPI IgG and ACA IgG. In the second trimester a statistically significant decrease of ACA IgG was found (p = 0.014). The difference of ACA IgM and anti-beta 2-GPI IgG and IgM was not statistically significant. Levels of foetoplacental antigens in anti-beta 2-GPI positive pregnant women were normal. CONCLUSION: A correlation between anti-beta 2-GPI antibodies and ACA was not found in our study. Anti-beta 2-GPI antibodies and ACA may be two different subpopulations of APA.