Fluorinated steroids are not superior to any treatment to ameliorate the outcome of autoimmune mediated congenital heart block: a systematic review of the literature and meta-analysis

OBJECTIVES

Fluorinated steroids are largely the therapeutic approach of autoimmune mediated congenital heart block (CHB). We performed a meta-analysis to assess the efficacy of fluorinated steroids for the treatment of CHB.

METHODS

Studies evaluating the efficacy of fluorinated steroids versus no treatment in CHB patients were identified in electronic databases. Random-effects model was used to pool odds ratio (OR) (with 95% CI) of live births as the primary outcome. ORs of CHB progression, pacemaker implantation and extranodal disease were the secondary outcome. Subgroup analysis according to CHB grade and study type was performed.

RESULTS

Data from nine studies involving 747 patients were analysed. The overall live birth rates were 86.8% and 86.7%, respectively, in the fluorinated steroids exposed foetuses and in the non-exposed ones. Fluorinated steroids did not ameliorate overall survival in CHB (OR 1.02; 95% CI: 0.65-1.61) with any significant statistical heterogeneity between studies (I2 0%, p=0.45). No significant differences for the progression of CHB, the pacing and the presence of extranodal disease were observed. Subgroup analysis revealed a significant protective role of fluorinated steroids for survival in 3rd degree CHB and for pacing in monocentric studies, OR 4.07; 95% CI: 1.10-15.08 and OR 0.15; 95% CI: 0.02-0.99, respectively.

CONCLUSIONS

This meta-analysis shows that fluorinated steroids are not superior to any treatment in patients with CHB in terms of live birth, prevention of progression of incomplete CHB, pacemaker implantation and extranodal disease. Thus, considering their side effects, their use in CHB patients should be discouraged.

AB0378 UPGRADING THERAPY STRATEGY IMPROVES PREGNANCY OUTCOME IN ANTIPHOSPHOLIPID SYNDROME: A COHORT MANAGEMENT STUDY

Background:

While it is generally agreed that pregnant APS patients should receive personalized treatment, evidence-based guidelines for these patients continue to be lacking.

Objectives:

The current study was designed as a management cohort study aiming to evaluate the efficacy and safety of different treatment strategies for pregnant APS patients in the attempt to provide some practical suggestions for attending physicians.

Methods:

One-hundred-twenty-seven consecutive pregnancies were assessed; 87 (68.5%) with a history of pregnancy morbidity alone were treated with prophylactic low molecular weight heparin (LMWH)+low-dose aspirin (LDA, 100 mg) [Group I] and 40 (31.5%) with a history of thrombosis and/or severe pregnancy complications with therapeutic LMWH+LDA [Group II]. LMWH doses were increased throughout the pregnancies depending on the patients’ weight gain, and treatment was switched to a more intensive one at the first sign of maternal/fetal complications. The study’s primary outcome was live births.

Results:

There were no significant differences in live birth rate between Group I (95.4%) and Group II (87.5%). Even, fetal complication rate was similar in the two groups; the Group II nevertheless had a higher prevalence of maternal and neonatal complications (p=0.0005 and p=0.01, respectively) and registered a significantly lower gestational age at delivery and birth weight (p=0.0001 and p=0.0005, respectively). Two patients in Group I switched to Group II therapy, six patients in Group II switched to a more intensive treatment strategy (weekly plasma exchange+ fortnightly intravenous immunoglobulins in addition to therapeutic LMWH+LDA). Comparison of the clinical and laboratory characteristics between patients who had shifted to a more intensive therapy and those who did not showed a significant prevalence of history of thrombosis ± pregnancy morbidity (p=0.02, OR 5.96, 95% CI 1.33-26.62) previous pregnancy complications (p=0.02, OR 8.32, 95% CI 1.67-41.3), triple aPL positivity (p <0.0001, OR 97.13, 95% CI 10.6-890) and pregnancy complications (p<0.0001, OR 197,7, 95% CI 10.57-3699) in upgrading group, instead single aPL positivity significantly prevailed (p=0.003, OR 0.06, 95% CI 0.008-0.58) in non-upgrading group. Logistic regression analysis demonstrated that triple aPL positivity was an independent factor for switching to a more effective therapy protocol (p <0.0001, OR 98, 95% CI 10.7-897.54). All eight switched patients achieved a live birth.

Conclusion:

Using adjusted LMWH doses and upgrading therapy at the first signs of pregnancy complications led to a high rate of live births in a relatively large group of APS patients. The study outlines the criteria for prescribing appropriate therapy for various subsets of these patients and for switching/upgrading the treatment protocol when it is no longer sufficient. Unfortunately, for the moment there are no evidence-based guidelines on the ideal additional treatment in refractory to conventional therapy APS patients. The present results will hopefully help point the direction of future clinical trials investigating the efficacy and safety of the different therapies on large numbers of APS pregnant patients in order to identify the benefits and limits of different treatment strategies administered from the beginning of pregnancy.

Disclosure of Interests:

Ariela Hoxha Speakers bureau: Celgene, UCB, Novartis, Sanofi, Werfen, Maria Favaro: None declared, Antonia Calligaro: None declared, Teresa Del Ross: None declared, Alessandra Teresa Ruffatti: None declared, Chiara Infantolino: None declared, Marta Tonello: None declared, Elena Mattia: None declared, Amelia Ruffatti: None declared

Upgrading Therapy Strategy Improves Pregnancy Outcome in Antiphospholipid Syndrome: A Cohort Management Study

The current study evaluates the efficacy and safety of different treatment strategies for pregnant patients with antiphospholipid syndrome. One hundred twenty-seven consecutive pregnancies were assessed; 87 (68.5%) with a history of pregnancy morbidity alone were treated with prophylactic low molecular weight heparin (LMWH) + low-dose aspirin (LDA, 100 mg) (group I) and 40 (31.5%) with a history of thrombosis and/or severe pregnancy complications with therapeutic LMWH + LDA (group II). LMWH doses were increased throughout the pregnancies depending on the patients' weight gain, and treatment was switched to a more intensive one at the first sign of maternal/fetal complications. The study's primary outcome was live births. There were no significant differences in live birth rate between group I (95.4%) and group II (87.5%). Even fetal complication rate was similar in the two groups; group II nevertheless had a higher prevalence of maternal and neonatal complications (p = 0.0005 and p = 0.01, respectively) and registered a significantly lower gestational age at delivery and birth weight (p = 0.0001 and p = 0.0005, respectively). Two patients in group I switched to group II therapy, six patients in group II switched to a more intensive treatment strategy (weekly plasma exchange + fortnightly intravenous immunoglobulins in addition to therapeutic LMWH + LDA). The multivariate analysis uncovered that triple antiphospholipid antibodies positivity was an independent factor leading to a more intensive therapy. All eight switched patients achieved a live birth. Study results revealed that adjusted LMWH doses and switching therapy at first signs of severe pregnancy complications led to a high rate of live births in antiphospholipid syndrome patients.

Clinical value of anti-domain I-β2Glycoprotein 1 antibodies in antiphospholipid antibody carriers. A single centre, prospective observational follow-up study

BACKGROUND

There seems to be a clear correlation between antibodies against domain I (anti-DI) of β2Glycoprotein I and severe clinical profiles in antiphospholipid syndrome (APS) patients. We investigated the clinical significance of anti-DI antibodies in a cohort of aPL carriers.

METHODS

One hundred and five carriers persistently positive for IgG anti-β2Glycoprotein 1 antibodies (a-β2GPI) and/or IgG anticardiolipin (aCL) and/or lupus anticoagulants (LAC) were tested for the presence of anti-DI antibodies using the QUANTA Flash® Beta2GPI-Domain I chemiluminescence immunoassay.

RESULTS

Anti-DI antibodies were detected in 44 aPL carriers (41.9%) and they were significantly associated to triple aPL positivity (LAC plus IgG a-β2GPI plus IgG aCL antibodies). Isolated LAC and a-β2GPI antibodies were significantly associated to anti-DI negative aPL carriers. During a 82.2 month mean follow-up, ten aPL carriers (9.5%) developed a first thrombotic event so becoming APS patients. Anti-DI antibodies, triple aPL positivity, thromboembolic risk factors and autoimmune disorders significantly prevailed in carriers becoming APS. Logistic regression analysis showed that anti-DI positivity was an independent risk factor for thrombosis.

CONCLUSIONS

Anti-DI antibody positivity can be considered a new risk factor predictive of the first thrombotic event in aPL carriers, instead, negative anti-DI may be useful to identify low-risk aPL carriers.

Beyond thrombosis: Anti-β2GPI domain 1 antibodies identify late pregnancy morbidity in anti-phospholipid syndrome

Antibodies against β2 glycoprotein I (anti-β2GPI) have been identified as the main pathogenic autoantibody subset in anti-phospholipid syndrome (APS); the most relevant epitope is a cryptic and conformation-dependent structure on β2GPI domain (D) 1. Anti-β2GPI domain profiling has been investigated in thrombotic APS, leading to the identification of antibodies targeting D1 as the main subpopulation. In contrast, scarce attention has been paid to obstetric APS, hence this study aimed at characterizing the domain reactivity with regards to pregnancy morbidity (PM). To this end, 135 women with persistently positive, medium/high titre anti-β2GPI IgG, without any associated systemic autoimmune diseases and at least one previous pregnancy were included: 27 asymptomatic carriers; 53 women with obstetric APS; 20 women with thrombotic APS; and 35 women with both thrombotic and obstetric complications. Anti-D1 and anti-D4/5 antibodies were tested using a chemiluminescent immunoassay and a research ELISA assay, respectively (QUANTA Flash^® β2GPI Domain 1 IgG and QUANTA Lite^® β2GPI D4/5 IgG, Inova Diagnostics). Positivity for anti-D1 antibodies, but not anti-D4/5 antibodies, was differently distributed across the 4 subgroups of patients (p < 0.0001) and significantly correlated with thrombosis (χ2 = 17.28, p < 0.0001) and PM (χ2 = 4.28, p = 0.039). Patients with triple positivity for anti-phospholipid antibodies displayed higher anti-D1 titres and lower anti-D4/5 titres compared to women with one or two positive tests (p < 0.0001 and p = 0.005, respectively). Reactivity against D1 was identified as a predictor for PM (OR 2.4, 95% confidence interval [CI] 1.2-5.0, p = 0.017); in particular, anti-D1 antibodies were predictive of late PM, conveying an odds ratio of 7.3 (95% CI 2.1-25.5, p = 0.022). Positivity for anti-D1 antibodies was not associated with early pregnancy loss. Anti-D4/5 antibodies were not associated with clinical APS manifestations. As a whole, our data suggest that anti-D1 antibodies are significantly associated not only with thrombosis, but also with late PM, while positive anti-D4/5 antibodies are not predictive of thrombosis or PM.

Detection of autoantibodies to the p200-epitope of SSA/Ro52 antigen. A comparison of two laboratory assays

Background:

Anti-p200 antibodies have been receiving growing interest in view of findings associating their presence to risk of fetal autoimmune congenital heart block (CHB). The study compares and evaluates the performance of two assays currently being used for their detection.

Methods:

One hundred and sixteen pregnant women positive for anti-SSA/Ro52 antibodies were considered as the study population. Fifty women negative for anti-SSA/Ro52 antibodies were considered as the control population. Anti-p200 antibodies were analyzed using two home-made ELISA assays: one with biotinylated antigen and the other with free antigen.

Results:

The specificity of the p200-free assay was significantly higher with respect to that of the p200-biotin assay (p=0.023). Both methods showed a high area under curve (AUC), thus, a good accuracy. There was a significant prevalence of anti-p200 antibodies when the p200-free assay was used to analyze the sera of the pregnant women with CHB fetuses (p=0.007). Cohen’s κ and Spearman’s ρ coefficients showed a good concordance (0.71) and a high correlation (0.93), respectively.

Conclusions:

The p200-free assay with respect to the biotin-based method was more specific in detecting p200 antibodies in women positive for anti-SSA/Ro52 antibodies. In addition, only the p200-free method significantly found p200 antibodies in patients with fetal CHB.

Neem oil nanoemulsions: characterisation and antioxidant activity

The aim of the present work is to develop nanoemulsions (NEs), nanosized emulsions, manufactured for improving the delivery of active pharmaceutical ingredients. In particular, nanoemulsions composed of Neem seed oil, contain rich bioactive components, and Tween 20 as nonionic surfactant were prepared. A mean droplet size ranging from 10 to 100 nm was obtained by modulating the oil/surfactant ratio. Physicochemical characterisation was carried out evaluating size, ζ-potential, microviscosity, polarity and turbidity of the external shell and morphology, along with stability in simulated cerebrospinal fluid (CSF), activity of Neem oil alone and in NEs, HEp-2 cell interaction and cytotoxicity studies. This study confirms the formation of NEs by Tween 20 and Neem oil at different weight ratios with small and homogenous dimensions. The antioxidant activity of Neem oil alone and in NEs was comparable, whereas its cytotoxicity was strongly reduced when loaded in NEs after interaction with HEp-2 cells.

Antiphosphatidylserine/prothrombin antibodies as biomarkers to identify severe primary antiphospholipid syndrome

Background:

Anti-phosphatidylserine/prothrombin (aPS/PT) antibodies have begun to be considered potentional biomarkers for antiphospholipid syndrome (APS). This cohort study investigate the role of aPS/PT antibodies as a risk factor for severe APS by evaluating the association between those antibodies and clinical/laboratory profiles of APS.

Methods:

Plasma/serum samples from 197 APS patients, 100 healthy subjects and 106 patients with autoimmune diseases were collected. IgG/IgM aPS/PT antibodies were assayed using commercial ELISA kit.

Results:

Prevalences of IgG and IgM aPS/PT (p<0.0001 and p=0.0009, respectively) and their titres (p<0.0001 and p=0.0002, respectively) were significantly higher in thrombosis/pregnancy group with respect to pregnancy morbidity alone. Prevalences of IgG and IgM aPS/PT (p<0.0001 and p=0.0004, respectively) and their mean levels (p=0.0001 for both) were significantly higher in the prematurity linked to life-threatening obstetric complications group with respect to miscarriage group. There was a significant relationship between IgG and IgM aPS/PT (p=0.001 and p=0.0002) and their mean levels were higher (p=0.0004 and p=0.0002, respectively) in the thrombotic microangiopathy group, considered a milestone manifestation of catastrophic APS. The relationship between IgG and IgM aPS/PT was significant and mean levels were higher in triple positive antiphospholipid antibody patients than in double and single positivity ones (p<0.0001 for all).

Conclusions:

APS/PT antibodies were associated to severe thrombosis, severe pregnancy complications inducing prematurity, and vascular microangiopathy, all generally associated to high risk APS forms requiring strong therapy.

Low titer, isolated anti Ro/SSA 60 kd antibodies is correlated with positive pregnancy outcomes in women at risk of congenital heart block

Congenital heart block (CHB) is an autoantibody mediated disorder presumably caused by placental transmission of maternal autoantibodies to Ro/SSA 52 kd, p200, Ro/SSA 60 kd, La/SSB ribonucleoproteins. This study investigated the clinical significance of isolated anti-Ro/SSA 52 kd, anti-p200, anti-Ro/SSA 60 kd, and anti-La/SSB antibodies in positive pregnant patients. One hundred sixty-three pregnant women positive to anti-Ro/SSA 52 kd and/or anti-Ro/SSA 60 kd and/or anti-La/SSB antibodies were prospectively enrolled in the study. Anti-Ro52, anti-Ro60, anti-p200, and anti-La antibodies were assayed using home-made ELISA assays. Isolated antibody positivity was found in 25 women (15.3%), while multiple antibody positivity in 138 (84.7%). Twenty-four developed CHB, and the 139 had a favorable pregnancy outcome. The prevalence of isolated anti-Ro/SSA 60 kd antibodies was significantly higher (p < 0.046) as the prevalence of lower mean antibody titers (p < 0.0001) in the later group. Confirmation of these results by large-scale studies could lead clinicians to recommend less stringent fetal echocardiography monitoring in women with isolated anti-Ro/SSA 60 kd antibodies.

Relationship between antiphosphatidylserine/prothrombin and conventional antiphospholipid antibodies in primary antiphospholipid syndrome

BACKGROUND

Antiphosphatidylserine/prothrombin complex (aPS/PT) antibodies are emerging as an important marker for antiphospholipid syndrome (APS). We aimed to compare their performance with that of conventional antiphospholipid antibodies (aPL) such as lupus anticoagulant (LA), anticardiolipin (aCL), and anti-β2-glycoprotein I (anti-β2GPI) in APS and to assess their frequency in APS-negative (APS-ne) patients.

METHODS

We considered 160 APS patients and 128 APS-ne patients with clinical criteria for APS but tested negative for conventional aPL. Immunoglobulin (Ig)G/IgM aPS/PT, IgG/IgM aCL, and IgG/IgM anti-β2GPI were detected using ELISA assay and LA with a series of coagulation tests.

RESULTS

IgG aPS/PT were significantly associated with IgG aCL, IgG anti-β2GPI, and LA (p<0.0001 for all). IgM aPS/PT were significantly associated only with LA (p<0.0001) instead. There was a significant correlation between IgG aPS/PT and both IgG aCL and IgG anti-β2GPI levels (ρ=0.42 and ρ=0.40, respectively). Both IgG aPS/PT and IgM aPS/PT positivity significantly correlated with LA (ρ=0.44 and ρ=0.5, respectively). IgG and IgM aPS/PT were significantly more frequent in triple than in double and in single positivity (p<0.0001). According to multivariate analysis, IgG and/or IgM aPS/PT were independent risk factors for LA. APS/PT antibodies were found in 9.4% of the APS-ne patients vs. 2% of healthy control (p=0.043); those antibodies were significantly more frequent in the thrombosis with respect to the pregnancy morbidity subset (p=0.01).

CONCLUSIONS

Our data attribute a clinical relevance to both IgG and IgM aPS/PT antibodies. In particular, the significant prevalence of aPS/PT in APS-ne patients suggests including them as additional laboratory criterion for APS.

Maternal autoantibody profiles at risk for autoimmune congenital heart block: a prospective study in high-risk patients

Objective

This prospective study aimed to identify antibody profiles characterising mothers with fetuses developing congenital heart block (CHB) by comparing their antibody frequencies and levels with those in unaffected mothers.

Methods

Eighty-one consecutive pregnant patients positive to anti-Ro±anti-La antibodies, at high risk of developing fetal CHB were prospectively studied. The 16 patients with fetal CHB outcome were considered the study population and the 65 patients with normal pregnancy outcomes were considered the control cohort. Anti-Ro52, anti-Ro60, anti-p200 and anti-La antibodies were assayed using home-made ELISA assays.

Results

The prevalence of anti-p200 antibodies was significantly higher in the fetal CHB affected patients than in the controls (p=0.03). Combinations of anti-p200 with anti-Ro52 and anti-Ro60 antibodies were significantly more frequent in the women with fetuses developing CHB than in the controls (p=0.03 for all combinations). The women with fetal CHB had significantly higher mean anti-Ro52, anti-Ro60 and anti-p200 levels than the controls (p=0.003, p=0.0001 and p=0.04, respectively); mean anti-La/SSB level was not significantly different in the two cohorts (p=0.25).

Conclusions

Since anti-p200, anti-Ro52 and anti-Ro60 antibodies, especially at high level, seem to identify patients at increased risk of developing fetal CHB, their detection could recognise anti-Ro/La positive women at risk for having an infant with this rare, potentially dangerous disorder.

The clinical performance of a chemiluminescent immunoassay in detecting anti-cardiolipin and anti-β2 glycoprotein I antibodies. A comparison with a homemade ELISA method

BACKGROUND

Fully automated chemiluminescence immunoassays (CLIAs) are emerging technologies for the detection of anti-cardiolipin (aCL) and anti-β2 glycoprotein I (anti-β2GPI) antibodies for anti-phospholipid syndrome (APS) classification, which is commonly based on an enzyme-linked immunosorbent assay (ELISA) test result. CLIA and a homemade ELISA were used in this study to detect these antibodies, and their performances were compared.

METHODS

Sera were collected from 104 patients with primary APS, 88 seronegative subjects who met the clinical but not the laboratory criteria for APS, and 150 control subjects. IgG/IgM aCL and IgG/IgM anti-β2GPI antibodies were determined in the sera using a CLIA (HemosIL AcuStar®) and a homemade ELISA.

RESULTS

CLIA had a significantly lower comparative sensitivity for IgM aCL and IgG/IgM IgG anti-β2GPI antibodies; its comparative specificity was higher with respect to ELISA for IgM aCL and IgM anti-β2GPI antibodies. The two techniques showed a high, significant agreement (p<0.001) and a significant titer correlation (p<0.001). CLIA also detected IgG/IgM aCL and IgG anti-β2GPI antibodies in the seronegative patients. There was a significantly higher prevalence of IgG aCL and IgG anti-β2GPI antibodies (p<0.001 and p=0.01, respectively) in those patients with respect to that in the control population.

CONCLUSIONS

Despite a lower comparative sensitivity, CLIA showed a higher comparative specificity for some aPL and a good level of agreement and correlation with a homemade ELISA. CLIA also detected some aCL and anti-β2GPI antibodies in the seronegative patients not usually identified by homemade ELISA.

Inhibition of autophagy in EBV-positive Burkitt's lymphoma cells enhances EBV lytic genes expression and replication

Autophagy, an important degradation system involved in maintaining cellular homeostasis, serves also to eliminate pathogens and process their fragments for presentation to the immune system. Several viruses have been shown to interact with the host autophagic machinery to suppress or make use of this cellular catabolic pathway to enhance their survival and replication. Epstein Barr virus (EBV) is a γ-herpes virus associated with a number of malignancies of epithelial and lymphoid origin in which establishes a predominantly latent infection. Latent EBV can periodically reactivate to produce infectious particles that allow the virus to spread and can lead to the death of the infected cell. In this study, we analyzed the relationship between autophagy and EBV reactivation in Burkitt's lymphoma cells. By monitoring autophagy markers and EBV lytic genes expression, we demonstrate that autophagy is enhanced in the early phases of EBV lytic activation but decreases thereafter concomitantly with increased levels of EBV lytic proteins. In a cell line defective for late antigens expression, we found an inverse correlation between EBV early antigens expression and autophagosomes formation, suggesting that early after activation, the virus is able to suppress autophagy. We report here for the first time that inhibition of autophagy by Bafilomycin A1 or shRNA knockdown of Beclin1 gene, highly incremented EBV lytic genes expression as well as intracellular viral DNA and viral progeny yield. Taken together, these findings indicate that EBV activation induces the autophagic response, which is soon inhibited by the expression of EBV early lytic products. Moreover, our findings open the possibility that pharmacological inhibitors of autophagy may be used to enhance oncolytic viral therapy of EBV-related lymphomas.

Abstract 4568: Inhibition of autophagy in EBV-positive Burkitt's lymphoma cells enhances EBV lytic genes expression and replication

Autophagy, an important degradation system involved in maintaining cellular homeostasis, serves also to eliminate pathogens and process their fragments for presentation to the immune system. Several viruses have been shown to interact with the host autophagic machinery to suppress or make use of this cellular catabolic pathway to enhance their survival and replication. Epstein Barr virus (EBV) is a γ-herpes virus associated with a number of malignancies of epithelial and lymphoid origin in which establishes a predominantly latent infection. EBV lytic cycle characterized by the sequential expression of immediate early (IE), early and late antigens results in the production of infectious particles which allow the virus to spread. In this study we analyzed the relationship between EBV and autophagy after inducing the virus productive cycle in Burkitt's lymphoma (BL) cells. By monitoring autophagy markers and EBV lytic genes expression, we demonstrate that autophagy is enhanced in the early phases of EBV lytic activation but decreases thereafter concomitantly with increased levels of EBV lytic proteins. In a cell line defective for late antigens expression, we found an inverse correlation between EBV early antigens expression and autophagosomes formation indicating that early after activation, the virus is able to suppress autophagy. We report that inhibition of autophagy by Bafilomycin A1 or shRNA knockdown of beclin1 gene, enhance EBV lytic genes expression as well as intracellular viral DNA and viral progeny yield. Taken together, these findings indicate that viral replication induces an autophagic response which can inhibit the further expression of EBV early lytic products. Moreover, our findings open the possibility to utilize pharmacological modulators of autophagy to control EBV infection and treat EBV-related lymphomas.

Citation Format: Alessandra De Leo, Francesca Colavita, Fabiola Ciccosanti, Gian Maria Fimia, Paul Lieberman, Elena Mattia. Inhibition of autophagy in EBV-positive Burkitt's lymphoma cells enhances EBV lytic genes expression and replication. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4568. doi:10.1158/1538-7445.AM2015-4568

IgA anticardiolipin and IgA anti-β2 glycoprotein I antibody positivity determined by fluorescence enzyme immunoassay in primary antiphospholipid syndrome

BACKGROUND

Primary antiphospholipid syndrome (PAPS) is an autoimmune disease characterized by thrombosis and/or pregnancy morbidity as well as blood antiphospholipid (aPL) antibodies such as anticardiolipin (aCL), anti-β2 glycoprotein I (anti-β2GPI) antibodies of the IgG/IgM isotype and lupus anticoagulant (LA). The clinical significance of aCL and anti-β2GPI antibodies of the IgA isotype in PAPS is still a controversial issue.

METHODS

Sera and plasma were collected from 84 PAPS patients (54 with thrombosis and/or pregnancy morbidity and 30 with pregnancy morbidity alone), 66 seronegative patients (subjects with clinical manifestations of PAPS although with negative results on conventional antiphospholipid antibody testing), and 78 healthy blood donors. IgA aCL and IgA anti-β2GPI were determined using fluorescence enzyme immunoassay (FEIA), (EliATM, Phadia AB, Uppsala, Sweden). For comparison purposes, the sera were also tested for IgG/IgM aCL/anti-β2GPI antibodies using the same immunoassay method. LA was assayed following internationally accepted guidelines.

RESULTS

Present respectively in 19% and 50% of the PAPS patients studied, IgA aCL and IgA anti-β2GPI antibody frequencies were both statistically significant (p=0.001 and p<0.001, respectively). The mean titers of both IgA aCL and IgA anti-β2GPI antibodies were higher in the thrombotic patients, but only the latter were significantly associated with thrombosis. Isolated IgA anti-β2GPI antibody positivity was significantly prevalent (p=0.04) in seven (10.6%) of the seronegative patients.

CONCLUSIONS

Positivity to IgA anti-β2GPI antibody detected using FEIA was found to be clinically relevant in PAPS patients. Moreover the prevalence of isolated IgA anti-β2GPI antibody positivity was significant in the seronegative patients.

A contribution to detection of anticardiolipin and anti-β2glycoprotein I antibodies: Comparison between a home-made ELISA and a fluorescence enzyme immunoassay

BACKGROUND

Currently, ELISA for detection of anticardiolipin (aCL) and anti-β2glycoprotein I (anti-β2GPI) antibodies is not standardized. Recently, few studies have compared the performance of ELISA with that of fluorescence enzyme immunoassay (FEIA), but they have produced debatable results. The aim of this investigation was to compare ELISA with FEIA results in detecting aCL and anti-β2GPI antibodies.

METHODS

The study cohort included 94 primary antiphospholipid syndrome (PAPS) patients, 65 subjects with the clinical criteria for PAPS classification but ELISA negative for the laboratory criteria and 165 control subjects. Serum IgG/IgM aCL/anti-β2GPI antibodies were determined using FEIA-EliA™ and a home-made ELISA.

RESULTS

The sensitivities of the two methods were similar with the exception of IgM aCL which was found to be significantly higher in the PAPS patients using the ELISA method, even if IgM aCL was detected at a low level by both techniques. The two assays had a comparable specificity, a high/significant agreement and a significant correlation between the antibody levels. FEIA testing uncovered no significant prevalence of any antiphospholipid (aPL) antibody in the ELISA negative patients.

CONCLUSION

Our results suggest that FEIA is comparable to a home-made ELISA.

Resveratrol inhibits proliferation and survival of Epstein Barr virus-infected Burkitt's lymphoma cells depending on viral latency program

Resveratrol (3,4',5-trihydroxy-trans-stilbene), a polyphenolic natural product, shows chemopreventive properties against several cancers, heart diseases, inflammation, and viral infections. Epstein Barr virus (EBV), a γ-herpesvirus, contributes to the development of several human cancers including Burkitt's lymphoma (BL). In this study, we asked whether treatment with resveratrol would affect the viability of EBV-positive BL cells displaying different forms of latency. We report here that resveratrol, regardless of EBV status, induces caspase-dependent apoptosis by arresting cell-cycle progression in G(1) phase. However, resveratrol strongly induced apoptosis in EBV(-) and latency I EBV(+) cells, whereas latency II and latency III EBV(+) BL cells showed a survival advantage that increased with the extent of the pattern of viral gene expression. Resveratrol-induced cell-cycle arrest and apoptosis occurred in association with induction of p38 MAPK phosphorylation and suppression of ERK1/2 signaling pathway. Moreover, NF-κB DNA-binding activity was inhibited in all BL lines except EBV(+) latency III cells. LMP1 oncogene, which is expressed in latency III phenotype, is involved with the higher resistance to the antiproliferative effect of resveratrol because siRNA-mediated inhibition of LMP1 greatly increased the sensitivity of latency III BL cells as well as that of lymphoblastoid cell lines to the polyphenol. We propose that a combined resveratrol/siRNA strategy may be a novel approach for the treatment of EBV-associated B-cell malignancies in which the viral pattern of gene expression has been defined.

Epstein-Barr virus lytic cycle activation alters proteasome subunit expression in Burkitt's lymphoma cells

We have shown that Epstein-Barr virus (EBV) lytic cycle activation in Burkitt's lymphoma (BL) cells down-regulates chymotrypsin- and caspase-like activities of the proteasome. The aim of the present study was to evaluate whether EBV activation might also affect proteasome subunit composition. Our results indicate that, independently of the latency program established in the host cells, induction of the EBV lytic cycle reduces the expression of the proteasomal components β5, β1 and β2i, whereas it increases that of β2, β1i, PA28α and PA28β. The modulation of the composition and enzymatic activities of the proteolytic complex are indicative of a less efficient generation of viral immunoepitopes.

Inhibition of p38 MAP kinase pathway induces apoptosis and prevents Epstein Barr virus reactivation in Raji cells exposed to lytic cycle inducing compounds

Background

EBV lytic cycle activators, such as phorbol esters, anti-immunoglobulin, transforming growth factor β (TGFβ), sodium butyrate, induce apoptosis in EBV-negative but not in EBV-positive Burkitt's lymphoma (BL) cells. To investigate the molecular mechanisms allowing EBV-infected cells to be protected, we examined the expression of viral and cellular antiapoptotic proteins as well as the activation of signal transduction pathways in BL-derived Raji cells exposed to lytic cycle inducing agents.

Results

Our data show that, following EBV activation, the latent membrane protein 1 (LMP1) and the cellular anti-apoptotic proteins MCL-1 and BCL-2 were quickly up-regulated and that Raji cells remained viable even when exposed simultaneously to P(BU)₂, sodium butyrate and TGFβ. We report here that inhibition of p38 pathway, during EBV activation, led to a three fold increment of apoptosis and largely prevented lytic gene expression.

Conclusion

These findings indicate that, during the switch from the latent to the lytic phase of EBV infection, p38 MAPK phosphorylation plays a key role both for protecting the host cells from apoptosis as well as for inducing viral reactivation. Because Raji cells are defective for late antigens expression, we hypothesize that the increment of LMP1 gene expression in the early phases of EBV lytic cycle might contribute to the survival of the EBV-positive cells.

Inhibition of Poly(ADP-ribose)polymerase impairs Epstein Barr Virus lytic cycle progression

BACKGROUND

Poly(ADP-ribosylation) is a post-translational modification of nuclear proteins involved in several cellular events as well as in processes that characterize the infective cycle of some viruses. In the present study, we investigated the role of poly(ADP-ribosylation) on Epstein-Barr Virus (EBV) lytic cycle activation.

RESULTS

Inhibition of PARP-1 by 3-aminobenzamide (3-ABA) during EBV induction, diminished cell damage and apoptosis in the non-productive Raji cell line while markedly reducing the release of viral particles in the productive Jijoye cells. Furthermore, incubation with 3-ABA up-regulated the levels of LMP1 and EBNA2 latent viral proteins. At the same time, it slightly affected the expression of the immediate early BZLF1 gene, but largely down-regulated the levels of the early BFRF1 protein. The modulation of the expression of both latent and lytic EBV genes appeared to be post-transcriptionally regulated.

CONCLUSION

Taken together the data indicate that PARP-1 plays a role in the progression of EBV lytic cycle and therefore, PARP inhibitors might represent suitable pharmacological adjuncts to control viral spread in EBV productive infection.

Down-regulation of proteolytic complexes following EBV activation in BL cells

In Burkitt's lymphoma cells, Epstein Barr virus (EBV) latency products interact with the ubiquitin-proteasome system to promote episomal maintenance and immunological evasion while the tripeptidylpeptidase II (TPPII) functions as an alternative protease. In the present study, we have examined the activities and levels of the proteasome and TPPII complex in Raji and in Akata cells after induction of EBV lytic cycle. The results show that the chymotrypsin-like and caspase-like activities of the proteasome were substantially reduced in Raji and Akata cells. Similarly, TPPII activity was diminished in both cell lines but was recovered in Akata cells at longer time after induction. Protein levels of the alpha/beta subunits of the 20S proteasome and TPPII concentration decreased to different extents after EBV activation, whereas the ubiquitin binding S6' subunit of the 19S regulatory complex increased three to fourfold along with the levels of ubiquitin-conjugates. Collectively, these observations demonstrate impairment of two major cellular proteolytic systems at the onset of EBV lytic infection.

Inhibition of Epstein Barr Virus LMP1 gene expression in B lymphocytes by antisense oligonucleotides: uptake and efficacy of lipid-based and receptor-mediated delivery systems

Epstein Barr Virus (EBV), is associated with an increasing number of lymphoid and epithelial malignancies. Among the genes expressed by EBV during latency, LMP1 plays a key role for growth transformation and immortalization of B lymphocytes. We have previously shown that antisense oligonucleotides (ONs) directed to LMP1 mRNA, effectively suppressed LMP1 gene expression and substantially reduced proliferation of the infected cells. The use of antisense phosphodiester oligonucleotides as therapeutic agents is limited by inefficient cellular uptake and intracellular transport to the target mRNA. We tested the ability of three cationic carriers internalized by different pathways, to increase the delivery of anti-LMP1-ON to their site of action in EBV-infected B lymphocytes. We report here that liposomes, dendrimers or transferrin-polylysine-conjugated ON were internalized by the cells at an extent several fold higher than that of the naked oligomers. However, only the delivery system exploiting the transferrin receptor pathway of internalization, was able to vectorize biologically active antisense LMP1-ON.

Antisense to Epstein Barr Virus-encoded LMP1 does not affect the transcription of viral and cellular proliferation-related genes, but induces phenotypic effects on EBV-transformed B lymphocytes

It is generally accepted that Epstein-Barr virus (EBV) latent genes EBNA-2, EBNA-3A, -3C, EBNA-LP and LMP1 are essential for growth transformation and immortalization of B lymphocytes. Among these genes, LMP1 plays a key role in the survival and dissemination of the infected B cells by inducing anti-apoptotic genes and surface expression of several activation antigens and adhesion molecules. We have previously shown that antisense oligodeoxynucleotides directed to LMP1 mRNA, effectively suppress LMP1 gene expression and substantially reduce B95.8 cell proliferation. In this study, we have used antisense LMP1 oligomers to investigate whether LMP1 suppression might influence the expression of latent EBV genes with oncogenic potential, anti-apoptotic genes, or affect the phenotype of EBV-infected B95.8 cells. Our data show that LMP1 suppression does not affect the transcription of EBNA-2, EBNA-3A, -3B and -3C genes, or that of bcl-2 and mcl-1 anti-apoptotic genes. In contrast, consistent modifications in the expression of CD39, CD54, CD23, CD11 and CD10 molecules were observed in B95.8 cells after treatment with antisense LMP1. Our findings support the possibility for using LMP1 antisense oligomers as therapeutics in EBV-associated tumors.

Interactions of Epstein-Barr virus origins of replication with nuclear matrix in the latent and in the lytic phases of viral infection

Eukaryotic DNA is organized into domains or loops generated by the attachment of chromatin fibers to the nuclear matrix via specific regions called scaffold or matrix attachment regions. The role of these regions in DNA replication is currently under investigation since they have been found in close association with origins of replication. Also, viral DNA sequences, containing the origins of replication, have been found attached to the nuclear matrix. To investigate the functional role of this binding we have studied, in Raji cells, the interaction between Epstein-Barr virus (EBV) origins of replication and the nuclear matrix in relation to the viral cycle of infection. We report here that both the latent (ori P) and the lytic (ori Lyt) EBV origins of replication are attached to the nuclear matrix, the first during the latent cycle of infection and the second after induction of the lytic cycle. These findings suggest that the binding of the origins of replication with the nuclear matrix modulates viral replication and expression in the two different phases of infection.

Differentiation-specific nuclear matrix proteins cross-linked to DNA by cis-diammine dichloroplatinum

DNA-protein cross-linkages were performed in intact undifferentiated and differentiated-HL60 cells by the action of cis-diammine dichloroplatinum. Total nuclear matrix proteins and DNA cross-linked nuclear matrix proteins were resolved by two-dimensional gel electrophoresis. The comparison of the electrophoretic patterns allowed the identification of a set of differentiation-induced nuclear matrix proteins cross-linked to DNA. One of these proteins binds cloned histone SAR sequences. Our results outline an experimental strategy for isolating and characterizing nuclear matrix components that may play a fundamental role in the overall control and coordination of gene expression during differentiation.

Induction of nuclear lamins A/C during in vitro-induced differentiation of F9 and P19 embryonal carcinoma cells

Lamin B is the major constituent of the nuclear lamina of undifferentiated mouse embryonal carcinoma cells. The full complement of the three major lamins A, B, and C, found in somatic mammalian cells, is acquired after induction of differentiation in vitro by certain drugs. In this study we have examined the time course of lamin A/C expression in the two embryonal carcinoma cell lines F9 and P19. We show here that lamins A/C are detectable in these cell lines, at the mRNA level and at the protein level, after 3 days of growth in media containing retinoic acid or retinoic acid + 3-isobutyl-1-methylxanthine. The data reported here indicate that the expression of lamins A/C is mainly regulated at the transcriptional level and occurs when the cells, by morphological and functional criteria, have differentiated along their developmental pathway.

Binding of matrix attachment regions to lamin B1

Eukaryotic chromatin is organized into topologically constrained loops that are attached to the nuclear matrix. The regions of DNA that interact with the matrix are called matrix attachment regions (MARs). We studied the spatial distribution of MAR-binding sites in the nuclear matrix from rat liver cells, following a combined biochemical and ultrastructural approach. We found that MAR-binding sites are distributed equally over the internal fibrogranular network and the peripheral nuclear lamina. Internal and peripheral binding sites have similar binding characteristics: both sets of binding sites show specific and saturable binding of MARs from different organisms. By means of a DNA-binding protein blot assay and in vitro binding studies, we identified lamin B1 as a MAR-binding protein, which provides evidence for a specific interaction of DNA with the nuclear lamina.

Role of protein synthesis in the accumulation of ferritin mRNA during exposure of cells to iron

The iron-induced biosynthesis of ferritin is regulated at the translational level via multiple mechanism. A prolonged exposure of cells to iron leads to a marked increase in ferritin mRNA levels caused by stabilization of the message. Here we show that this stabilization requires the synthesis de novo of an iron-inducible protein factor.

Multiple post-transcriptional regulatory mechanisms in ferritin gene expression

We have investigated the mechanisms involved in the regulation of ferritin biosynthesis in K562 human erythroleukemia cells during prolonged exposure to iron. We show that, upon addition of hemin (an efficient iron donor) to the cell culture, the rate of ferritin biosynthesis reaches a maximum after a few hours and then decreases. During a 24-hr incubation with the iron donor the concentrations of total ferritin heavy (H) and light (L) subunit mRNAs rise 2- to 5-fold and 2- to 3-fold, respectively, over the control values, while the amount of the protein increases 10- to 30-fold. The hemin-induced increment in ferritin subunit mRNA is not prevented by deferoxamine, suggesting that it is not directly mediated by chelatable iron. In vitro nuclear transcription analyses performed on nuclei isolated from control cells and cells grown in the presence of hemin indicate that the rates of synthesis of H- and L-subunit mRNAs remain constant. We conclude that iron-induced ferritin biosynthesis is governed by multiple post-transcriptional regulatory mechanisms. We propose that exposure of cells to iron leads to stabilization of ferritin mRNAs, in addition to activation and translation of stored H- and L-subunit mRNAs.

Regulation of intracellular iron distribution in K562 human erythroleukemia cells

Following a pulse with 59Fe-transferrin, K562 erythroleukemia cells incorporate a significant amount of 59Fe into ferritin. Conditions or manipulations which alter the supply of iron to cells result in changes in the rate of ferritin biosynthesis with consequent variations in the size of the ferritin pool. Overnight exposure to iron donors such as diferric transferrin or hemin increases the ferritin level 2-4- or 6-8-fold above that of the control, respectively. Treatment with the anti-human transferrin receptor antibody, OKT9 (which reduces the iron uptake by decreasing the number of transferrin receptors) lowers the ferritin level by approximately 70-80% with respect to the control. The fraction of total cell-associated 59Fe (given as a pulse via transferrin) that becomes ferritin bound is proportional to the actual ferritin level and is independent of the instantaneous amount of iron taken up. This has allowed us to establish a curve that correlates different levels of intracellular ferritin with corresponding percentages of incoming iron delivered to ferritin. Iron released from transferrin appears to distribute to ferritin according to a partition function; the entering load going into ferritin is set for a given ferritin level over a wide range of actual amounts of iron delivered.

Quantitative determination of intracellular, ferritin-associated radioactive iron by high-performance liquid chromatography and immunoprecipitation

Antibodies raised against ferritin preparations of diverse origin provide an uncertain reagent for quantitation of the ferritin present in specific cell lysates. Utilizing K562 cells, a human leukemic cell line, techniques are described to resolve and to quantitate the ferritin-bound cytosolic iron. Processing the cell lysates by HPLC employing an anion-exchange or hydrophobic interaction column resulted in recovery of a single, ferritin-containing radioactive peak widely separated from the bulk of the non-ferritin-bound iron. Comparison of the yield obtained by chromatography with that by immunoprecipitation confirmed both the specificity and the quantitation of the antibody technique.

Hemin, chelatable iron, and the regulation of transferrin receptor biosynthesis

We have examined the mechanism by which hemin regulates the expression of the human transferrin receptor. Previous work led to the suggestion that the regulatory signal is provided by heme (Ward J. H., Jordan, I., Kushner, J. P., and Kaplan, J. (1984) J. Biol. Chem. 259, 13235-13240). We demonstrated that hemin regulates the expression of the receptor via alterations in the rate of receptor biosynthesis. However, this effect can be completely abolished by addition of desferrioxamine, an intracellular iron chelator. Competition curves demonstrate that desferrioxamine and hemin affect the same intracellular iron pool. Since the chelator cannot remove iron from heme, we propose that hemin acts simply by delivering iron to a chelatable iron pool and that levels of chelatable iron provide the regulatory signal for expression of the transferrin receptor gene.

Isolation of chitin synthetase from Saccharomyces cerevisiae. Purification of an enzyme by entrapment in the reaction product

Chitin synthetase, in the zymogen form, was extracted with digitonin from a particulate fraction from Saccharomyces cerevisiae and converted into active form by treatment with immobilized trypsin. When the activated enzyme was incubated with UDP-GlcNAc and other components of an assay mixture, a chitin precipitate formed, trapping a large portion of the synthetase. The enzyme was easily extracted frm the chitin gel with a recovery of approximately 50% and an enrichment of approximately 100-fold. Further purification was obtained by repeating the chitin step. After polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, the purified synthetase showed a major band corresponding to Mr 63,000, a weaker band at Mr 74,000, and some other minor bands. Under nondenaturing conditions, an Mr of 570,000 was calculated for the enzyme from Stokes radius and sedimentation coefficient determinations. After electrophoresis in a nondenaturing gel and incubation with the components of the standard assay, chitin was formed and precipitated in the gel, yielding an opaque band. Soluble oligosaccharides were not precursors for insoluble chitin, suggesting that synthesis of chitin chains takes place by a processive mechanism. N-Acetylglucosamine stimulated the purified synthetase only slightly and did not participate as a primer in the reaction. The same chain length, somewhat more than 100 units of GlcNAc, was determined in samples of chitin that had been synthesized either in vivo, or with a membrane preparation or with purified synthetase. These results suggest that chitin synthetase itself is capable both of initiating chitin chains without a primer and of determining their length.

Biosynthetic regulation of the human transferrin receptor by desferrioxamine in K562 cells

Treatment of K562 cells with the iron chelator desferrioxamine results in the gradual increase in total cell receptors for transferrin. Receptor number rises 2.5-4.5-fold over 24 h and remains at the elevated level if the chelator is continuously present. Preincubation of the chelator with ferric chloride abolishes the effect. The drug has no effect on the 7-h half-life of the receptor. The increased number of receptors can be accounted for by a specific increase in the rate of receptor biosynthesis which reaches 3-4 times that seen in untreated cells by 6 h after the addition of the chelator. Isolation of mRNA from treated cells reveals that, after 8 h in the presence of desferrioxamine, there is a 3-fold increase in the specific translation of transferrin receptor over untreated cells. Total protein synthesis is not changed under these conditions.