Beta-2-glycoprotein-I, infections, antiphospholipid syndrome and therapeutic considerations

Antiphospholipid antibodies in patients with stroke during COVID-19: A role in the signaling pathway leading to platelet activation

Background

Several viral and bacterial infections, including COVID-19, may lead to both thrombotic and hemorrhagic complications. Previously, it has been demonstrated an "in vitro" pathogenic effect of "antiphospholipid" antibodies (aPLs), which are able to activate a proinflammatory and procoagulant phenotype in monocytes, endothelial cells and platelets. This study analyzed the occurrence of aPL IgG in patients with acute ischemic stroke (AIS) during COVID-19, evaluating the effect of Ig fractions from these patients on signaling and functional activation of platelets.

Materials and methods

Sera from 10 patients with AIS during COVID-19, 10 non-COVID-19 stroke patients, 20 COVID-19 and 30 healthy donors (HD) were analyzed for anti-cardiolipin, anti-β2-GPI, anti-phosphatidylserine/prothrombin and anti-vimentin/CL antibodies by ELISA. Platelets from healthy donors were incubated with Ig fractions from these patients or with polyclonal anti-β2-GPI IgG and analyzed for phospho-ERK and phospho-p38 by western blot. Platelet secretion by ATP release dosage was also evaluated.

Results

We demonstrated the presence of aPLs IgG in sera of patients with AIS during COVID-19. Treatment with the Ig fractions from these patients or with polyclonal anti-β2-GPI IgG induced a significant increase of phospho-ERK and phospho-p38 expression. In the same vein, platelet activation was supported by the increase of adenyl nucleotides release induced by Ig fractions.

Conclusions

This study demonstrates the presence of aPLs in a subgroup of COVID-19 patients who presented AIS, suggesting a role in the mechanisms contributing to hypercoagulable state in these patients. Detecting these antibodies as a serological marker to check and monitor COVID-19 may contribute to improve the risk stratification of thromboembolic manifestations in these patients.

Anticardiolipin and anti-beta 2-glycoprotein I antibodies in patients with unexplained articular manifestations

OBJECTIVE

To determine the frequency of antiphospholipid antibodies (aPL) in patients with unexplained articular manifestations.

MATERIAL AND METHODS

Three hundred thirteen patients suffering from arthritis or arthralgia without evident cause and 266 healthy blood donors (HBD) were included in the study. Anticardiolipin antibodies (aCL) and anti-beta 2-glycoprotein I antibodies (aβ2GPI) were measured by ELISA.

RESULT

Out of the 313 patients, 250 were females and 63 were males. The mean age of patients was 49 ± 14 years (17-87 years). One hundred eleven patients have arthralgia and 202 have arthritis. The frequency of aCL and/or aβ₂ GPI (24.9%) was significantly higher in patients than in HBD (10.9%). The frequency of aβ2GPI was 23.6% in patients and 9.4% in the control group (p < 10^-3 ). aβ2GPI-IgA was significantly more frequent in patients than in the control group (20.4% vs. 7.5%, p < 10^-3 ). aβ2GPI was most commonly observed than aCL in patients (23.6% vs. 6.4%, p < 10^-6 ). IgA isotype of aβ2GPI was the most frequent in 20.4% of patients while IgG and IgM were detected in 5.4% and 2.9% respectively.

CONCLUSION

This study showed that aPL were common in patients with articular manifestations and were mainly directed against β₂ GPI. The role of these antibodies remains to be specified.

Zonal cortical scarring and tubular thyroidization in kidney biopsies of patients with SLE-histologic indicator for antiphospholipid antibodies

Antiphospholipid antibody syndrome (APS) is an acquired prothrombotic autoimmune disease caused by the presence of antibodies against anionic phospholipids or plasma proteins bound to phospholipids on cell membranes. It can be a primary disease or secondary to other autoimmune diseases, most commonly systemic lupus erythematosus (SLE). Laboratory testing for antiphospholipid antibodies (aPL) may be only transiently positive, so APS could be missed until a catastrophic thrombotic episode or pregnancy morbidity occurs. In the kidneys, this manifests as thrombotic microangiopathy (TMA), and patients present with hypertensive urgency and acute kidney injury. However, APS may not always have a catastrophic presentation but instead a more smoldering course. Kidney biopsy may not show obvious active TMA lesions but rather only chronic injury in the form of zonal cortical scarring and tubular thyroidization. Still, it may warrant anticoagulation therapy. So it is important to recognize this pattern of injury in the biopsy. Herein, we retrospectively study the correlation between presence of this histologic feature in kidney biopsies of SLE patients and positive aPL testing results (anticardiolipin antibodies and/or lupus anticoagulant). Kidney biopsies of SLE patients from 2004 to 2015 ( n = 186) were screened for presence or absence of zonal cortical scarring. Their electronic medical records were reviewed for aPL results. Our study showed low sensitivity (33%) but higher positive predictive value (62%), specificity (89%) and negative predictive value (71%). This histologic finding is therefore not a sensitive screening tool, but if present, greatly increases the likelihood of underlying aPL. We want to emphasize that recognition of this histologic feature in the biopsies of SLE patients is important so as not to miss the opportunity to treat with anticoagulation therapy and possibly slow down the chronic renal damage.

Protective Effects of Reduced Beta 2 Glycoprotein I on Liver Injury in Streptozotocin (STZ)-Diabetic Rats by Activation of AMP-Activated Protein Kinase

Background

Protective effects of reduced beta 2 glycoprotein I (Rβ2GPI) against vascular injury of diabetes mellitus have been extensively investigated. However, the effects of Rβ2GPI on liver injury in diabetic animals have not been reported.

Material/Methods

A diabetic rat model of was produced by systemic injection of streptozotocin (STZ). Rats were divided into a normal control group, a model group, and an Rβ2GPI treatment group (N=6 in each group). After treatments, blood serum and liver tissue were collected to test the protection of Rβ2GPI. AMP-activated protein kinase (AMPK) was detected by immunohistochemistry and Western blotting.

Results

Our results revealed that Rβ2GPI reduced blood glucose, serum creatinine, and urea nitrogen levels, as well as serum inflammation cytokines, including interleukin (IL)-6, tumor necrosis factor (TNF)-a and C-reactive protein in the diabetic rats. Importantly, Rβ2GPI prevented liver injury in the diabetic rats as confirmed by hematoxylin-eosin (H&E) staining, alanine transaminase, aspartate transaminase, and gamma-glutamyl transferase. Reactive oxygen species (ROS) were promoted by diabetic modeling and were attenuated by Rβ2GPI administration. Moreover, Rβ2GPI significantly reduced liver catalase, malondialdehyde, and superoxide dismutase levels in the diabetic rats. Rβ2GPI reduced liver glycolipid storage in STZ diabetic rats. Both immunohistochemistry and Western blotting demonstrated that Rβ2GPI promoted AMPK phosphorylation in the diabetic rats.

Conclusions

Our data proved that Rβ2GPI prevented liver injury in diabetic rats, likely through activating the AMPK signaling pathway.

Effects of reduced β2 glycoprotein I on high glucose‑induced cell death in HUVECs

Reduced β2 glycoprotein I (β2GPI) has been demonstrated to exhibit a beneficial effect in diabetic atherosclerosis and retinal neovascularization. However, the effect of reduced β2GPI on vascular disorders in diabetic mellitus (DM) remains to be elucidated. The present study established a high glucose‑induced injury model using human umbilical cords veins (HUVECs) and evaluated the protective effects of reduced β2GPI against the injury. The data demonstrated that a low concentration of reduced β2GPI (0.5 µM) mitigated high glucose‑induced cell loss, decreased nitric oxide (NO) production and resulted in calcium overloading. Mechanically, reduced β2GPI additionally reversed high glucose‑induced phosphatase and tensin homolog (PTEN) accumulation, decrease of protein kinase B phosphorylation and nitric oxide synthase activity, and increase of cyclooxygenase‑2 activity. It was further confirmed that PTEN inhibitor‑bpV (1 µM) exhibited similar effects to those resulting from reduced β2GPI. Overall, the data revealed that reduced β2GPI exerts protective effects from glucose‑induced injury in HUVECs, potentially via decreasing PTEN levels. The present study suggests reduced β2GPI may act as a novel therapeutic strategy for the treatment of vascular disorders in DM.

The environment and antiphospholipid syndrome

The etiology of autoimmune diseases is multifactorial. The degree to which genetic and environmental factors influence susceptibility to autoimmune diseases is poorly defined. It is believed that versatile clinical presentations of autoimmune diseases stem from various combinations of the genetic and environmental factors. One of the newly diagnosed autoimmune diseases is the antiphospholipid syndrome (APS). APS is characterized by vascular thrombosis, and/or pregnancy morbidity associated with anticardiolipin (aCL), anti-β2-glycoprotein-I (anti-β2GPI) and lupus anticoagulant (LAC).

The role of anti-phospholipid antibodies in autoimmune reproductive failure

Anti-phospholipid antibodies (aPL) are autoantibodies that are associated with thrombosis and a range of pregnancy complications including recurrent pregnancy loss and pre-eclampsia. The three clinically relevant, well-characterized aPL are anti-cardiolipin antibodies, lupus anticoagulant and anti-beta-2-glycoprotein I (β2GPI) antibodies. aPL do not bind directly to phospholipids but instead bind to a plasma-binding ‘cofactor’. The most extensively studied cofactor is β2GPI, whose role in pregnancy is not fully elucidated. Although the pathogenicity of aPL in recurrent pregnancy loss is well established in humans and animal models, the association of aPL with infertility does not appear to be causative. aPL may exert their detrimental effects during pregnancy by directly binding trophoblast cells of the placenta, altering trophoblast signalling, proliferation, invasion and secretion of hormones and cytokines, and by increasing apoptosis. Heparin is commonly used to treat pregnant women with aPL; however, as thrombotic events do not occur in the placentae of all women with aPL, it may exert a protective effect by preventing the binding of aPL to β2GPI or by acting through non-thrombotic pathways. The aim of this review is to present evidence summarizing the current understanding of this field.

β2-Glycoprotein I-Dependent Anti-Cardiolipin Antibodies Associated With Periodontitis in Patients With Systemic Lupus Erythematosus

BACKGROUND

It was reported that patients with systemic lupus erythematosus (SLE) exhibited increased levels of anticardiolipin (anti-CL) antibodies, a class of antiphospholipid antibodies associated with thrombosis. β2-glycoprotein I (β2GPI) has been considered as the actual target antigen for anti-CL antibodies. This study investigates the association of periodontal infection with anti-CL antibodies in patients with SLE.

METHODS

Fifty-three SLE female patients and 56 healthy female volunteers were recruited in this case-control study. All participants received periodontal examinations. The presence of Porphyromonas gingivalis and Treponema denticola in saliva and plaque samples was detected by polymerase chain reaction. Levels of serum anti-CL and anti-β2GPI antibodies were examined using enzyme-linked immunosorbent assay.

RESULTS

Patients with SLE exhibited more periodontal attachment loss and increased titers of serum anti-CL and anti-β2GPI antibodies compared with healthy controls. Patients with active SLE who harbored P. gingivalis or P. gingivalis together with T. denticola intraorally exhibited significantly higher anti-CL and anti-β2GPI antibodies than those without these bacteria. Anti-CL and anti-β2GPI antibody levels correlated positively with clinical attachment level. Furthermore, increased anti-β2GPI antibody levels were significantly associated with C-reactive protein and erythrocyte sedimentation rate.

CONCLUSIONS

Elevated anti-CL and anti-β2GPI antibody levels were associated with periodontopathic bacteria and periodontal breakdown in patients with SLE. Periodontitis might be a modifiable risk factor for SLE.

Diet, microbiota and autoimmune diseases

There is growing evidence that the commensal bacteria in the gastrointestinal tract (the gut microbiota) influence the development of autoimmunity in rodent models. Since humans have co-evolved with commensals for millennia, it is likely that people, who are genetically predisposed to autoimmunity, harbor gut microbial communities that similarly influence the onset and/or severity of disease. Beyond the current efforts to identify such disease-promoting or -preventing commensals ("pathobionts" or "symbionts"), it will be important to determine what factors modulate them. Dietary changes are known to affect both the composition and function of the gut microbial communities, which in turn can alter the innate and adaptive immune system. In this review, we focus on the relationships between diet, microbiota, and autoimmune diseases. We hypothesize that the beneficial and life-prolonging effects of caloric restriction on a variety of autoimmune models including lupus might partly be mediated by its effects on the gut microbiome and associated virome, the collection of all viruses in the gut. We give recent examples of the immunomodulatory potential of select gut commensals and their products or diet-derived metabolites in murine models of arthritis, multiple sclerosis, and type 1 diabetes. Lastly, we summarize the published phenotypes of germ-free mouse models of lupus and speculate on any role of the diet-sensitive microbiome and virome in systemic lupus and the related antiphospholipid syndrome.

Evaluation of serum anti-cardiolipin antibodies after non-surgical periodontal treatment in chronic periodontitis patients

The present study investigated the effect of non-surgical periodontal therapy on serum level of anti-cardiolipin antibodies (aCLA), which are potentially involved in the pathogenesis of cardiovascular diseases in periodontal patients. Twenty volunteers (11 females and 9 males) with the mean age of 40.55 years participated in this study. Generalized chronic periodontitis was diagnosed through clinical periodontal examination at baseline visit. This examination included measuring the probing pocket depth and clinical attachment loss. Plaque index and gingival index were also recorded. After baseline examination, all the subjects received full-mouth non-surgical periodontal treatment. Subjects returned for a final visit 6 weeks after the last session of scaling for reevaluation of the periodontal parameters. At baseline and final visits 2 ml of venous blood was collected from each patient and an available commercially enzyme-linked immunosorbent assay was used for analyzing aCLA (IgM and IgG). The collected data were analyzed using the paired sample t test. Mean levels of both forms of aCLA, before and after treatment, showed statistically significant difference (P = 0.003 for IgM and P = 0.001 for IgG). In addition, study results showed significant reductions in periodontal parameters after non-surgical periodontal therapy (P < 0.001). The results of this study suggested that successful periodontal therapy can improve the serum level of one of the inflammatory biomarkers involved in the cardiovascular problems.

Free radicals and endothelial dysfunction: potential positive effects of TNF-α inhibitors

OBJECTIVES

During the last decade many new biological immune modulators have entered the market as new therapeutic principles. Tumor necrosis factor (TNF)-α is a pro-inflammatory cytokine known to a have a key role in the pathogenic mechanisms of various immune-mediated or inflammatory diseases. However, TNF-α also plays a key role in endothelial dysfunction and, thus, in the development and progression of atherosclerosis. What, then, is the potential therapeutic role of TNF-α inhibitors?

METHODS

We analysed the current literature concerning the administration of TNF-α inhibitors and their potential benefits upon endothelial function.

RESULTS

TNF-α inhibitors decrease the serum levels of inflammatory markers such as TNF-α itself, CRP, IL-6, and increased the tissue expression of endothelial NO synthase and the vasodilatory response to bradykinin.

DISCUSSION

TNF-α inhibitors may change the progression of endothelial dysfunction and, thus, slow down the atherosclerotic process.

Sex-specific environmental influences on the development of autoimmune diseases

Sex differences in autoimmune diseases are evolutionarily tied to the fact that the female immune system is confronted with intense alterations during menstrual cycles, pregnancy and childbirth. These events may be associated with breaches in the mucosal epithelial layers that are shielding us from environmental factors. Associations between environmental agents and autoimmune diseases have been described extensively in prior studies. Little evidence, however, exists for sex-specific environmental effects on autoimmune diseases. In this review, we summarize studies involving this often-neglected aspect. We give examples of environmental factors that may influence the sex bias in autoimmunity. We conclude that most studies do not give insight into sex-specific environmental effects due to the influence of gender-selective social, occupational or other exposures. Prospective studies are needed in order to determine true sex-biased environmental influences. Finally, humanized murine models might aid in better understanding the mechanisms involved in sex-specific environmental effects on autoimmune diseases.

Evidence on the pathogenic role of auto-antibodies in acute cardiovascular diseases

Atherothrombosis is the major determinant of acute ischaemic cardiovascular events, such as myocardial infarction and stroke. Inflammatory processes have been linked to all phases of atherogenesis In particular, the identification of autoimmunity mediators in the complex microenvironment of chronic inflammation has become the focus of attention in both early and advanced atherogenic processes. Auto-antibodies against self-molecules or new epitopes generated by oxidative processes infiltrate atherosclerotic plaques and were shown to modulate the activity of immune cells by binding various types of receptors. However, despite mounting evidence for a pathophysiological role of autoantibodies in atherothrombosis, the clinical relevance for circulating autoantibodies in cardiovascular outcomes is still debated. This review aims at illustrating the mechanisms by which different types of autoantibodies might either promote or repress atherothrombosis and to discuss the clinical studies assessing the role of auto-antibodies as prognostic biomarkers of plaque vulnerability.

Infections and vaccines in the etiology of antiphospholipid syndrome

PURPOSE OF REVIEW

To present scientific evidence supporting the infectious origin for the antiphospholipid syndrome (APS) by molecular mimicry between pathogens, infection and vaccination with β2-glycoprotein I (β2-GPI) molecule.

RECENT FINDINGS

APS is characterized by the presence of pathogenic autoantibodies against β2-GPI. The infection etiology of APS was well established. Likewise, a link between vaccination such as tetanus toxoid may trigger antibodies targeting tetanus toxoid and β2-GPI, due to molecular mimicry between the two molecules. During the years, the pathogenic potential of anti-tetanus toxoid antibodies cross reactive with β2-GPI were found to be pathogenic in animal models, inducing experimental APS.

SUMMARY

Accumulated evidence supports that the presence of anti-β2-GPI antibodies is associated with a history of infections and the main mechanism to explain this correlation is molecular mimicry. The relationship between tetanus toxoid vaccination and APS reveals a novel view on the autoimmune/autoinflammatory syndrome induced by adjuvants (ASIA).

Endothelial dysfunction in rheumatic autoimmune diseases

Rheumatic autoimmune diseases have been associated with accelerated atherosclerosis and various types of vasculopathies. Atherosclerosis is an inflammatory condition which starts as a "response to injury" favoring endothelial dysfunction which is associated with increased expression of adhesion molecules, pro-inflammatory cytokines, pro-thrombotic factors, oxidative stress upregulation and abnormal vascular tone modulation. Endothelial dysfunction in rheumatic autoimmune diseases involves innate immune responses, including macrophages and dendritic cells expression of scavenger and toll-like receptors for modified or native LDL as well as neutrophil and complement activation, and dysregulation of adaptive immune responses, including proliferation of autoreactive T-helper-1 lymphocytes and defective function of dendritic and regulatory T cells. Specific differences for endothelial function among different disorders include: a) increased amounts of pro-atherogenic hormones, decreased amounts of anti-atherogenic hormones and increased insulin resistance in rheumatoid arthritis; b) autoantibodies production in systemic lupus erythematosus and antiphospholipid syndrome; c) smooth muscle cells proliferation, destruction of internal elastic lamina, fibrosis and coagulation and fibrinolytic system dysfunction in systemic sclerosis. Several self-antigens (i.e. high density lipoproteins, heat shock proteins, β2-glycoprotein1) and self-molecules modified by oxidative events (i.e. low density lipoproteins and oxidized hemoglobin) have been identified as targets of autoimmune responses. Endothelial dysfunction leads to accelerated atherosclerosis in rheumatoid arthritis, systemic lupus erythematosus and spondyloarthropaties whereas obliterative vasculopathy is associated with systemic sclerosis. In this paper, we will briefly review the most relevant information upon endothelial dysfunction and inflammatory mechanisms in atherosclerosis and we will summarize the similarities and differences in vascular disease patterns underlying different rheumatic autoimmune diseases.

The significance of autoantibodies against β2-glycoprotein I

The antiphospholipid syndrome (APS) is defined by the persistent presence of antiphospholipid antibodies in patients with a history of thrombosis and/or pregnancy morbidity, including fetal loss. APS is an autoimmune disease with a confusing name because the pathologic auto-antibodies are shown to be directed against the plasma protein β(2)-glycoprotein I and not against phospholipids. In fact, auto-antibodies that recognize phospholipids themselves are not associated with thrombosis but with infectious diseases. One of the intriguing questions is why autoantibodies against β(2)-glycoprotein I are so commonly found in both patients and the healthy. Several potential mechanisms have been suggested to explain the increased thrombotic risk in patients with these autoantibodies. In this overview, we will summarize our knowledge on the etiology of the autoantibodies, and we will discuss the evidence that identify autoantibodies against β(2)-glycoprotein I as the culprit of APS.

Case report: cytomegalovirus-induced thrombosis in an immunocompetent patient

Thrombotic manifestations of cytomegalovirus infection in immunocompetent individuals are rare. However, it has been postulated that cytomegalovirus infection can be both directly cytopathic and capable of inducing antiphospholipid antibodies due to shared "molecular mimicry" between cytomegalovirus virus antigens and antiphospholipid antibodies. The case of a previously well 30-year-old woman with primary cytomegalovirus infection complicated by splenic infarction and massive pulmonary embolus is described. The patient is unusual given the development of thromboses affecting both the arterial and venous circulation, associated with both transient anticardiolipin antibodies and persistently positive anti-β(2) glycoprotein I antibodies. The temporal relationship between the primary infection and thrombosis was suggestive of a pathogenic role for cytomegalovirus.

Superior vena cava syndrome – changing etiology in the third millennium

Superior vena cava syndrome (SVCS), is diagnosed following different degrees of central venous system obstruction, which traditionally was caused by infections, tumors or fibrosing mediastinitis. Recently the role of SVC thrombosis secondary to indwelling central venous devices or pacemaker leads as well as different hypercoagulable states have drawn much attention. In the current review we present a 58-year-old female patient who underwent recurrent pacemaker replacements due to recurrent infections. The patient was hospitalized with superior vena cava syndrome and multiple thrombi in the upper body circulation. Additionally the evaluation was conducted for thrombophilia, which revealed the presence of high titers of antiphospholipid antibodies, suggesting the concurrent diagnosis of the antiphospholipid syndrome (APS). This case reflects the changes in the etiology of SVCS, and the need for a comprehensive evaluation of patients, in the search for additional factors that may complicate a pacemaker insertion, such as the presence of antiphospholipid antibodies. We review the relevant literature and highlight the importance for an interdisciplinary approach in the treatment of SVCS nowadays.

Oxidative stress in cardiovascular inflammation: its involvement in autoimmune responses

Recently, it has become clear that atherosclerosis is a chronic inflammatory disease in which inflammation and immune responses play a key role. Accelerated atherosclerosis has been reported in patients with autoimmune diseases, suggesting an involvement of autoimmune mechanisms in atherogenesis. Different self-antigens or modified self-molecules have been identified as target of humoral and cellular immune responses in patients with atherosclerotic disease. Oxidative stress, increasingly reported in these patients, is the major event causing structural modification of proteins with consequent appearance of neoepitopes. Self-molecules modified by oxidative events can become targets of autoimmune reactions, thus sustaining the inflammatory mechanisms involved in endothelial dysfunction and plaque development. In this paper, we will summarize the best characterized autoantigens in atherosclerosis and their possible role in cardiovascular inflammation.

Autoantibodies directed against domain I of beta2-glycoprotein I

Patients diagnosed with the antiphospholipid syndrome typically suffer from vascular thrombosis, pregnancy morbidity, or a combination of the two. Due to the high prevalence of these clinical symptoms, the diagnosis of antiphospholipid syndrome is almost completely dependent on the detection of antiphospholipid antibodies in patient plasma. However, not every individual with antiphospholipid antibodies in his or her plasma suffers from thrombosis and/or pregnancy morbidity, which suggests the existence of different populations of antiphospholipid antibodies. Although many antigens have been identified in relation to the antiphospholipid syndrome, β2-glycoprotein I is regarded as clinically most significant. During the past decade, evidence has accumulated to suggest the presence of a dominant epitope on the first domain of β2-glycoprotein I. Several studies have detected a specific population of antibodies recognizing a cryptic epitope on domain I, at least comprising arginine 39 to arginine 43. In contrast to antibodies recognizing other domains of β2-glycoprotein I, anti-domain I antibodies are found to be highly associated with clinical symptoms. This review discusses several studies that have investigated a role for domain I within the antiphospholipid syndrome on a predominantly diagnostic level.

Characterization of antiphospholipid antibodies in chronic hepatitis B infection

BACKGROUND

Many infections are associated with antiphospholipid antibodies (aPLs). The purpose of this study was to investigate the prevalence, persistence, clinical significance, and characteristics of aPLs in hepatitis B virus (HBV)-infected patients.

METHODS

This study included 143 patients with HBV infection and 32 healthy individuals as controls. The presence of anticardiolipin antibodies (aCL Ab), anti-β(2)-glycoprotein I antibodies (β(2)GPI Ab), and lupus anticoagulant (LA) was assessed.

RESULTS

The total prevalence of aPLs in HBV-infected patients was 12.6% (18 of 143). Of these 18 patients, 15 had low to medium titers of aCL Ab (10 with IgM, 4 with IgG, and 1 with both isotypes). β(2)GPI Ab and LA were detected in 3 (2.1%) and 2 (1.4%) patients with HBV infection, respectively. In follow-up specimens from 14 patients with elevated levels of aCL Ab or β(2)GPI Ab, 10 (71.4%) showed the persistent presence of aPLs. No clinical manifestations related to aPLs were identified.

CONCLUSION

In HBV-infected patients, the most frequently detected antiphospholipid antibodies were IgM aCL Ab, which have a weak association with the clinical manifestations of APS. Unlike the transient presence reported for other infection-associated aPLs, most aPLs were persistently detected over a 12-week period in patients with HBV infection.

The role of infections in the immunopathogensis of systemic sclerosis--evidence from serological studies

Infections are believed to often play a role in the immunopathogenesis of autoimmune disorders; such is the case in systemic sclerosis (SSc). In order to evaluate the potential role infections may have on the pathogenesis of SSc, we assessed serological reactivity against various infectious agents in patients with SSc and compared them with healthy controls. Serological samples obtained from 80 patients with SSc were compared with 296 compatible healthy controls. Both groups were of European origin. All samples were tested for the presence of antibodies directed against hepatitis B virus, hepatitis C virus, toxoplasmosis, rubella, CMV, EBV, and Treponema pallidum. We applied Bio-Rad commercial and experimental kits to assess most antigens and ELISA assays to complete the panel. Patients with SSc had elevated IgM and IgG against Toxoplasma gondii and against CMV. Higher titers were also detected against the hepatitis B virus core protein (recombinant HBc antigen) using MONOLISA anti-HBc Plus commercial kit (Bio-Rad). A significantly higher rate of IgM antibodies against the capsid antigen of the EBV was detected in SSc patients compared with healthy controls, as well. These data demonstrate that antibodies against CMV, HBV, and toxoplasmosis were detected more often in patients with SSc. This association implies that infectious agents may have a role in disease pathogenesis and expression.

Association between periodontitis and anti-cardiolipin antibodies in Buerger disease

AIM

Anti-cardiolipin (CL) antibodies can be induced in Buerger disease (BD), an inflammatory occlusive disorder affecting peripheral blood vessels, in response to bacteria bearing homology to the TLRVYK peptide of a phospholipid-binding plasma protein beta-2-glycoprotein I. TLRVYK homologies are present in Porphyromonas gingivalis (TLRIYT) and Treponema denticola (TLALYK). This study investigated the association between periodontal infection and anti-CL antibodies in BD patients.

MATERIAL AND METHODS

Periodontal conditions were examined in 19 BD patients and 25 systemically healthy control subjects. All subjects were heavy smokers. Serum anti-CL, anti-TLRVYK, anti-TLRIYT, and anti-TLALYK antibodies were assessed using the enzyme-linked immunosorbent assay.

RESULTS

BD patients had a significantly higher prevalence of periodontitis, more severe periodontal destruction and increased titres of serum anti-CL, anti-TLRVYK, anti-TLRIYT, and anti-TLALYK antibodies compared with healthy subjects. The levels of anti-CL antibodies positively correlated with those of the three anti-peptide antibodies. Anti-CL antibody titres were significantly associated with the percentage of sites with clinical attachment level >or=4 mm in BD patients.

CONCLUSION

Elevated anti-CL antibody levels were associated with periodontal destruction in BD patients. Periodontopathic bacteria may serve as exogenous antigens that stimulate the anti-CL antibody production through molecular mimicry between the bacterial peptides and a host plasma protein.

Mechanisms of antiphospholipid antibody-associated pregnancy complications

Women with antiphospholipid syndrome (APS) and antiphospholipid antibodies (aPL) are at high risk for recurrent spontaneous miscarriage and late pregnancy complications, such as preeclampsia and preterm labor. Recent clinical and experimental observations suggest that the pathophysiology of pregnancy failure in patients with APS may involve inflammation at the maternal-fetal interface and disruption of normal trophoblast function and survival, rather than a pro-thrombotic event. While treatment with heparin and aspirin from early pregnancy has been shown to significantly increase the live birth rate in recurrent miscarriage patients with APS, the incidence of severe late pregnancy complications still remains high. This review will discuss what is currently known about the mechanisms by which aPL may compromise pregnancy outcome.

Antiphospholipid antibodies induce a pro-inflammatory response in first trimester trophoblast via the TLR4/MyD88 pathway

PROBLEM

Women with antiphospholipid antibodies (aPL) are at risk for recurrent miscarriage, pre-eclampsia, and pre-term labor. aPL target the placenta directly by binding to beta(2)-glycoprotein I (beta(2)GPI) expressed on the surface of trophoblast cells. The objective of this study was to determine the effects of aPL on trophoblast function and the mechanisms involved.

METHOD OF STUDY

First trimester trophoblast cells were treated with anti-beta(2)GPI monoclonal antibodies and patient-derived aPL, after which cell survival and function was evaluated.

RESULTS

We report that anti-beta(2)GPI antibodies trigger an inflammatory response in trophoblast, characterized by increased secretion of interleukin (IL)-8, MCP-1, GRO-alpha, and IL-1beta, and that this occurs in a TLR-4/MyD88-dependent manner. At high concentrations, these antibodies also induce caspase-mediated cell death. This was attenuated upon disabling of the MyD88 pathway, suggesting that anti-beta(2)GPI-induced inflammatory mediators compromise trophoblast survival by acting in an autocrine/paracrine manner. Enhanced IL-8, GRO-alpha, and IL-1beta secretion also occurred when trophoblast cells were incubated with antibodies from patients with antiphospholipid syndrome. Heparin, which acts as a pro-survival factor in human trophoblast, attenuated the anti-beta(2)GPI antibody-mediated cell death, and also the pro-inflammatory response, but only at high concentrations.

CONCLUSION

These findings demonstrate that aPL triggers a placental inflammatory response via the TLR-4/MyD88 pathway, which in turn compromises trophoblast survival. Thus, the TLR-4/MyD88 pathway may provide a new therapeutic target to improve pregnancy outcome in antiphospholipid syndrome patients.

Neonatal effects of maternal antiphospholipid syndrome

Antiphospholipid antibodies (aPL) can impair the physiologic development of a fetus during pregnancy not only by causing thrombosis of the placental vessels, but also by directly binding throphoblast cells and modifying their functions. Consequently, the presence of aPL in pregnant women is linked to an increased rate of pregnancy complications. These include recurrent early miscarriages, late fetal losses, and hypertensive disorders of gestation. In this clinical setting, preeclampsia is usually early and severe and can be complicated by the syndrome of hemolysis, elevated liver enzymes, and low platelet count (HELLP syndrome). The close association between aPL and obstetric pathology supports the inclusion of these manifestations in the clinical classification criteria of antiphospholipid syndrome. About 30% of children born to mothers with aPL passively acquire these autoantibodies; fortunately, the occurrence of thrombosis seems extremely rare in these babies. The prospective ongoing studies of children born to antiphospholipid syndrome patients reassure us about their general good health; however, some data suggest that learning difficulties might occur, possibly related to in utero exposure to aPL.

Increased expression of Matrix Metalloproteinase 9 in liver from NZB/W F1 mice received antibody against human parvovirus B19 VP1 unique region protein

Background

Human parvovirus B19 infection has been postulated to the anti-phospholipid syndrome (APS) in autoimmunity. However, the influence of anti-B19-VP1u antibody in autoimmune diseases is still obscure.

Methods

To elucidate the effect of anti-B19-VP1u antibodies in systemic lupus erythematosus (SLE), passive transfer of rabbit anti-B19-VP1u IgG was injected intravenously into NZB/W F1 mice.

Results

Significant reduction of platelet count and prolonged thrombocytopenia time were detected in anti-B19-VP1u IgG group as compared to other groups, whereas significant increases of anti-B19-VP1u, anti-phospholipid (APhL), and anti-double strand DNA (dsDNA) antibody binding activity were detected in anti-B19-VP1u group. Additionally, significant increases of matrix metalloproteinase-9 (MMP9) activity and protein expression were detected in B19-VP1u IgG group. Notably, phosphatidylinositol 3-phosphate kinase (PI3K) and phosphorylated extracellular signal-regulated kinase (ERK) proteins were involved in the induction of MMP9.

Conclusion

These experimental results firstly demonstrated the aggravated effects of anti-B19-VP1u antibody in disease activity of SLE.

Molecular mimicry of Aggregatibacter actinomycetemcomitans with beta2 glycoprotein I

INTRODUCTION

beta2-Glycoprotein I (beta 2GPI) is important in the suppression of coagulation, and antibodies against TLRVYK peptides on the beta 2GPI molecule are related to thrombosis. According to the Swiss-Prot database, Aggregatibacter actinomycetemcomitans leukotoxin c has sequences (SIRVYK) that are homologous to the TLRVYK peptides. The aim of this study was to investigate the effects of A. actinomycetemcomitans infection on the antibody response against SIRVYK peptides in patients with periodontitis.

METHODS

Serum immunoglobulin G (IgG) antibody and IgG subclass antibody titers against SIRVYK or TLRVYK peptides were measured by enzyme-linked immunosorbent assay in 46 patients with aggressive periodontitis (eight with localized disease, 38 with generalized disease), 28 patients with chronic periodontitis, and 20 periodontally healthy subjects. The presence of A. actinomycetemcomitans in plaque and saliva samples was determined using polymerase chain reaction.

RESULTS

The level of anti-SIRVYK antibodies was significantly higher in patients who were A. actinomycetemcomitans-positive than in A. actinomycetemcomitans-negative patients (P < 0.05) in the chronic periodontitis group. A similar trend was found in the antibody response to TLRVYK peptide; however, no statistically significant difference was seen between A. actinomycetemcomitans-positive and -negative patients. The A. actinomycetemcomitans-positive patients displayed significantly higher levels of anti-SIRVYK IgG2 and IgG3 antibodies than A. actinomycetemcomitans-negative patients (P < 0.05 and P < 0.05, respectively). The level of IgG2 was highest among the four IgG subclasses and it predominantly increased in patients who were A. actinomycetemcomitans-positive. Anti-TLRVYK antibody levels were significantly correlated with anti-SIRVYK IgG antibody levels.

CONCLUSION

The results suggest that A. actinomycetemcomitans infection may elicit anti-SIRVYK IgG antibodies and modify the anti-TLRVYK antibody response in patients with periodontitis by molecular mimicry with beta2GPI.

Antiphospholipid syndrome (APS): where does it come from?

The antiphospholipid syndrome (APS) is the most common acquired thrombophilia. It is characterized by venous and arterial thrombosis, recurrent pregnancy loss, and various other clinical manifestations in the presence of antiphospholipid antibodies (aPL). Like other autoimmune diseases, the etiology of APS derives from a combination of genetic and environmental factors. The most significant environmental factors in APS are infectious agents, followed by trauma and drugs. Infections can induce aPL and, in the catastrophic variant of APS, about one-third of cases are associated with a clear recent infection. On their formation, aPL have been clearly shown to be pathogenic, because they influence all arms of the coagulation system and because passive transfer and active immunization protocols have demonstrated. Therefore, in a genetically susceptible individual, exposure to one or more infectious agent can cause a molecular mimicry and result in the production of pathogenic aPL that can induce thrombosis and pregnancy loss. Identification of the epitopes within the beta-2-glycoprotein-I molecule that serves as the target for autoantibodies makes them the target for immunomodulation of the syndrome.

Lupus anticoagulant is significantly associated with inflammatory reactions in patients with suspected deep vein thrombosis

OBJECTIVE

Lupus anticoagulant (LA) and antiphospholipid antibodies (aPL) are suggested as risk factors for development of deep vein thrombosis (DVT) among patients without systemic lupus erythematosus (SLE). Other conditions, e.g. inflammation, are reported to induce LA and it is uncertain whether the association between LA and DVT is causal. In this study the associations between aPL, LA and inflammation were investigated in 170 consecutive patients without SLE, but with a tentative diagnosis of DVT.

MATERIAL AND METHODS

DVT was diagnosed in 64 patients. LA was determined according to the criteria of the International Society of Thrombosis and Haemostasis. The concentration of anticardiolipin (aCL) and beta(2)-glycoprotein I (anti-beta(2)-GPI) antibodies as well as C-reactive protein (CRP) was determined with sensitive and precise methods.

RESULTS

LA was demonstrated in 8 patients with DVT and in 10 patients without DVT, relative risk 1.33 (CI: 0.55-3.18). No significant association was observed between aCL or anti-beta(2)-GPI and DVT. Patients suffering from DVT had significantly higher concentrations of CRP than patients without DVT. However, CRP was also significantly higher in patients positive for LA than in patients without LA irrespective of the presence of DVT (p<0.001).

CONCLUSIONS

The present study supports a strong association between inflammatory reactions and development of LA in patients with suspected DVT, whereas no significant association was demonstrated between LA or aPL and DVT.

Induction of antiphospholipid antibodies and antiphospholipid syndrome-like autoimmunity in naive mice with antibody against human parvovirus B19 VP1 unique region protein

BACKGROUND

Previous studies have postulated a connection between human parvovirus B19 (B19) infection and anti-phospholipid antibodies (APhL). B19 infection and anti-phospholipid syndrome (APS) exhibit congruent symptoms. Recently, phospholipase A2 (PLA2)-like activity has been linked to the VP1 unique region (VP1u) of B19. However, the precise role of B19-VP1u in pathogenesis of autoimmunity is still obscure.

METHODS

To elucidate the roles of VP1u in B19 infection and autoimmunity, the reactivity of B19-VP1u proteins with various autoantibodies were evaluated by ELISA and immunoblotting. Rabbits were immunized with purified recombinant B19-VP1u protein to generate anti-sera. Absorption experiments were conducted to determine the binding specificity of rabbit anti-sera against B19-VP1u, cardiolipin (CL) and beta-2-glycoprotein I (beta2GPI). Moreover, the effects of passive transfer of polyclonal rabbit anti-B19-VP1u IgG antibodies on platelets, activated partial thromboplastin time (aPTT), and autoantibodies were assessed.

RESULTS

Autoantibodies against CL, beta2GPI, and phospholipid (PhL) in sera from patients with B19 infection, were cross-reactive with B19-VP1u. Consistently, sera from rabbits immunized with recombinant B19-VP1u protein displayed raised detectable immunoglobulins against B19-VP1u, CL, beta2GPI and PhL. Additionally, the mice immunized with anti-B19-VP1u IgG developed thrombocytopenia, prolongation of aPTT, and autoantibody against beta2GPI and PhL.

CONCLUSIONS

These experimental results suggested the association between B19-VP1u and production of anti-beta2GPI antibodies, APhL, and APS-like autoimmunity. Altogether, it may provide a clue in understanding the role of B19-VP1u in inducing autoantibodies and B19-associated APS manifestations.

Beta2-glycoprotein I and its clinical significance: from gene sequence to protein levels

In order to elucidate beta2-GPI at the DNA level and characterize its polymorphisms, mRNA expression, protein levels and clinical significance at each of these steps, a molecular review of beta2-GPI literature was performed. The human beta2-GPI complete nucleotide sequence has been reported and it consists of 8 exons separated by large introns. The beta2-GPI gene is polymorphic with four alleles. The distribution of point mutations can be significantly different between various racial populations. DNA variation studies of the beta2-GPI gene identified a total of 151 single-nucleotide polymorphisms, 26 of which are within regions with potential clinical significance. Southern blot analysis indicated the presence of one gene product only. An atypical TATA box and a hepatic nuclear factor-1 element are both essential for beta2-GPI promoter activity. Transcription factor binding sites for STAT, CREB, C/EBPbeta, NF-1, AP-1, NFAT, HNF-3beta and HNF-1 have been identified in the promoter region of the beta2-GPI gene by computer analysis. The beta2-GPI transcriptional signal of 1.5 kb was detected in Northern blot analysis and its 326-amino-acid sequence was found to be one of the most proline-rich eukaryotic proteins. Amino acid substitutions have been shown to be associated with loss of phospholipid binding, development and recognition of antiphospholipid antibodies.

Incidental discovery of high systemic lupus erythematosus disease activity associated with cytomegalovirus viral activity

We try to find the association of cytomegalovirus (CMV) infection and anti-beta2 glycoprotein 1 autoantibodies (anti-beta2 GP1), a key antibody in antiphospholipid syndrome (APS), among systemic lupus erythematosus (SLE) and cerebral vascular accident (CVA) patients. This retrospective study enrolled serum samples obtained from 87 SLE and 97 CVA patients who have been checked for the existence of anti-beta2 GP1. First, the prevalence rate of anti-CMV IgG and IgM in patients with and without anti-beta2 GP1 were compared. Second, the prevalence of anti-CMV IgG and IgM were compared between SLE and CVA patients. Last, this study analyzed the clinical characteristics and disease activity in SLE patients with positive anti-CMV IgM and IgG. No difference existed in the prevalence rate of anti-CMV IgG and IgM between positive or negative anti-beta2 GP1 serum samples in both SLE and CVA patients. However, the prevalence of anti-CMV IgM was significantly higher in the SLE group than in the CVA group. Severity of clinical features and SLEDAI scores were considerably higher in patients with positive anti-CMV IgM than in SLE patients with negative anti-CMV IgM. Very impressively, all IgM-positive SLE samples (9/9) carrying highest levels of anti-CMV IgG, indicated reactivation of the latent CMV infection. Hence, it suggests that CMV reactivation might contribute toward the disease flare in some SLE patients. In future, a prospective and longitudinal study is stongly indicated.

Antiphospholipid syndrome

PURPOSE OF REVIEW

To review the recently published studies that can guide physicians in the management of persistently antiphospholipid antibody (aPL)-positive patients.

RECENT FINDINGS

Two recent prospective randomized controlled trials of two intensities of warfarin concluded that both moderate and high-intensity anticoagulation are similarly protective in antiphospholipid syndrome patients after the first thrombosis. Despite lack of controlled studies, there is experimental evidence that hydroxychloroquine and statins may play a role in the management of aPL-positive patients. In the mouse model of antiphospholipid syndrome that involves the injection of high-titer antiphospholipid syndrome human serum, complement activation is essential in aPL-mediated fetal loss and heparin prevents aPL-induced complement activation.

SUMMARY

Primary thrombosis prevention in persistently aPL-positive individuals lacks an evidence-based approach; elimination of reversible thrombosis risk factors and prophylaxis during high-risk periods is crucial. Secondary thrombosis prevention in persistently aPL-positive individuals lacks a risk-stratified approach; although the current recommendation is life-long warfarin, the necessity, duration, and the intensity of warfarin are still debated. Catastrophic antiphospholipid syndrome patients usually receive a combination of anticoagulation, corticosteroids, intravenous immunoglobulin, and plasma exchange; there is a clear need to test new agents. A common strategy to prevent fetal loss in aPL-positive patients with history of pregnancy morbidities is low-dose aspirin and heparin; if patients fail this regimen, the next step is the addition of intravenous immunoglobulin although this is not supported by controlled studies. Currently, there is no evidence that anticoagulation is effective for nonthrombotic manifestations of antiphospholipid antibodies.

Anti-phospholipid antibodies following vaccination with recombinant hepatitis B vaccine

This study was undertaken to evaluate the possible role of hepatitis B recombinant vaccine inducing the synthesis of IgG and IgM anti-cardiolipin antibodies (aCL), antibodies against beta(2)GPI (anti-beta(2)GPI), lupus anti-coagulant (LA), anti-nuclear antibodies and antibodies against extractable nuclear antigens (anti-ENA). The study population consisted of 85 healthy students (63 female, 22 male; mean age 20.8 years), vaccinated with three doses of recombinant DNA hepatitis B vaccine. One month after vaccination with the first dose of hepatitis B vaccine a minority of vaccinated individuals showed changes in IgG or IgM aCL or anti-beta(2)GPI or LA activity (P < 0.001). Among subjects in whom changes of IgG anti-beta(2)GPI were observed, a significantly higher number of increased (8/85) than decreased (2/85) values were found (P < 0.01). Analyses of paired data showed that differences in aCL or anti-beta(2)GPI levels before vaccination or 1 month later did not reach statistical significance. In two people aCL transitorily reached medium positivity after the first dose of hepatitis B vaccine with a drop 5 months later. Similar evident anti-beta(2)GPI fluctuation was also observed in one person. Another participant was initially low positive for IgG anti-beta2GPI and the levels were increasing after vaccination. Two participants became positive for anti-nuclear antibodies during 6 months' follow-up. There were no sex-dependent differences in tested antibodies observed and no associations between levels of aPL and levels of anti-HBV antibodies. We conclude that HBV can induce aPL, although rarely. In genetically susceptible individuals or together with some other triggers such combination might confer the risk of developing a continuous autoimmune response in an individual.

The infectious etiology of the antiphospholipid syndrome: links between infection and autoimmunity

Like many other autoimmune diseases, the antiphospholipid syndrome (APS) is considered as of a multifactorial etiology, mainly genetic susceptibility coinciding with environmental triggers, of which infectious agents are considered most prominent. Different clinical and experimental studies of the beta2 glycoprotein I (beta 2 GPI) molecule, one of the target autoantigens in APS, have linked infection to the development of APS. Using a peptide phage library, it has been shown that target epitopes of beta 2 GPI share similarities with common infectious pathogens. Also, circulating anti-beta 2 GPI antibodies have been identified in the sera of patients with different infectious conditions, and have been associated with various clinical APS manifestations. Molecular mimicry as a key mechanism linking infection and APS has been demonstrated in experimental models. In these studies, APS was induced by immunization of mice to various microbial pathogens. Anti-beta 2 GPI titers were found to be especially high following immunization with Haemophilus influenzae, Neisseria gonorrheae or tetanus toxoid. These findings contribute greatly to the understanding of APS pathogenesis, as well as create new directions for therapy modalities, namely specific peptide toleragens and antimicrobial treatment.

Infection, vaccines and other environmental triggers of autoimmunity

The etiology of autoimmune diseases is still not clear but genetic, immunological, hormonal and environmental factors are considered to be important triggers. Most often autoimmunity is not followed by clinical symptoms unless an additional event such as an environmental factor favors an overt expression. Many environmental factors are known to affect the immune system and may play a role as triggers of the autoimmune mosaic.Infections: bacterial, viral and parasitic infections are known to induce and exacerbate autoimmune diseases, mainly by the mechanism of molecular mimicry. This was studied for some syndromes as for the association between SLE and EBV infection, pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection and more. Vaccines, in several reports were found to be temporally followed by a new onset of autoimmune diseases. The same mechanisms that act in infectious invasion of the host, apply equally to the host response to vaccination. It has been accepted for diphtheria and tetanus toxoid, polio and measles vaccines and GBS. Also this theory has been accepted for MMR vaccination and development of autoimmune thrombocytopenia, MS has been associated with HBV vaccination. Occupational and other chemical exposures are considered as triggers for autoimmunity. A debate still exists about the role of silicone implants in induction of scleroderma like disease.Not only foreign chemicals and agents have been associated with induction of autoimmunity, but also an intrinsic hormonal exposure, such as estrogens. This might explain the sexual dimorphism in autoimmunity.Better understanding of these environmental risk factors will likely lead to explanation of the mechanisms of onset and progression of autoimmune diseases and may lead to effective preventive involvement in specific high-risk groups. So by diagnosing a new patient with autoimmune disease a wide anamnesis work should be done.

New Facet of Antiphospholipid Antibodies

Since the aCL test was first described, several reports have described the heterogeneity of aPL, which binds to different anionic phospholipids, proteins, or to a phospholipid-protein complex. It has been recently reported that antiphospholipids (aPLs) from the sera of patients with the antiphospholipid syndrome (APS) are able to bind some newly identified antigens, the lyso(bis)phosphatidic acid (LBPA), lipid restricted to the late endosomes, and the sulfatides, acidic glycosphingolipids involved in the hemostatic process. Of interest, aLBPAs are present in the sera of a large number of patients with APS showing similar sensitivity and specificity compared to anti-beta(2) glycoprotein I antibodies (abeta(2)-GPIs) and close association with lupus anticoagulant. Moreover, beta(2)-GPI binds to sulfatides and the majority of the aPL reacting with cardiolipin-beta(2)-GPI complex also react with the sulfatide-beta(2)-GPI complex. Different mechanisms involved in the production of autoantibodies in autoimmune diseases have been proposed and, among them, apoptosis or programmed cell death seems to play a leading role. The relocation of CL and its metabolites during apoptosis may represent an in vivo trigger for the generation of aCL, and the higher reactivity of sera from APS patients to monolysocardiolipin, the immediate degradation product of mitochondrial CL validates this hypothesis. Finally, increasing evidence suggests that oxidative stress could be a pathogenic link between aPL and thrombosis, and antioxidant treatment may have some efficacy in preventing the clinical manifestations of this syndrome.

A concept on the role of Helicobacter pylori infection in autoimmune pancreatitis

Autoimmune pancreatitis, an inflammatory process of the pancreas due to an autoimmune mechanism establishing etiology of chronic pancreatitis, is characterized by the presence of autoantibodies, hypergammaglobulinemia, pancreatic enlargement, pancreatic duct strictures, and pathologic features of fibrotic changes with intense, mainly lymphocytic infiltrations, which may contribute to tissue destruction probably by apoptosis. In almost 60% of the cases, this type of pancreatitis coexists with other autoimmune diseases such as Sjogren's syndrome, sclerosing extrahepatic cholangitis, primary biliary cirrhosis, autoimmune hepatitis, or other extrapancreatic disorders, and recently with gastric peptic ulceration. The diversity of extrapancreatic lesions with similar histopathologic findings suggests general involvement of the digestive system in this disease, although the presence of such involvement has not been fully elucidated. Similarly, Helicobacter pylori (H. pylori) infection, a well known cause of gastric ulcer, has been associated, via molecular mimicry of host structures by its constituents with the same autoimmune conditions, also characterized by fibrotic changes and/or lymphoplasmacytic inflammations, accompanied by aberrations of T cell apoptosis that contribute to hepatobiliary- or extrahepatic-tissue destruction. Considering that H. pylori is involved in the pathogenesis and pathophysiology of these autoimmune disorders, we propose that this organism might trigger autoimmune pancreatitis through induction of autoimmunity and apoptosis.

A concept on the role of Helicobacter pylori infection in autoimmune pancreatitis

Autoimmune pancreatitis, an inflammatory process of the pancreas due to an autoimmune mechanism establishing etiology of chronic pancreatitis, is characterized by the presence of autoantibodies, hypergammaglobulinemia, pancreatic enlargement, pancreatic duct strictures, and pathologic features of fibrotic changes with intense, mainly lymphocytic infiltrations, which may contribute to tissue destruction probably by apoptosis. In almost 60% of the cases, this type of pancreatitis coexists with other autoimmune diseases such as Sjogren's syndrome, sclerosing extrahepatic cholangitis, primary biliary cirrhosis, autoimmune hepatitis, or other extrapancreatic disorders, and recently with gastric peptic ulceration. The diversity of extrapancreatic lesions with similar histopathologic findings suggests general involvement of the digestive system in this disease, although the presence of such involvement has not been fully elucidated. Similarly, Helicobacter pylori (H. pylori) infection, a well known cause of gastric ulcer, has been associated, via molecular mimicry of host structures by its constituents with the same autoimmune conditions, also characterized by fibrotic changes and/or lymphoplasmacytic inflammations, accompanied by aberrations of T cell apoptosis that contribute to hepatobiliary- or extrahepatic-tissue destruction. Considering that H. pylori is involved in the pathogenesis and pathophysiology of these autoimmune disorders, we propose that this organism might trigger autoimmune pancreatitis through induction of autoimmunity and apoptosis.

A concept on the role of Helicobacter pylori infection in autoimmune pancreatitis

Autoimmune pancreatitis, an inflammatory process of the pancreas due to an autoimmune mechanism establishing etiology of chronic pancreatitis, is characterized by the presence of autoantibodies, hypergammaglobulinemia, pancreatic enlargement, pancreatic duct strictures, and pathologic features of fibrotic changes with intense, mainly lymphocytic infiltrations, which may contribute to tissue destruction probably by apoptosis. In almost 60% of the cases, this type of pancreatitis coexists with other autoimmune diseases such as Sjogren's syndrome, sclerosing extrahepatic cholangitis, primary biliary cirrhosis, autoimmune hepatitis, or other extrapancreatic disorders, and recently with gastric peptic ulceration. The diversity of extrapancreatic lesions with similar histopathologic findings suggests general involvement of the digestive system in this disease, although the presence of such involvement has not been fully elucidated. Similarly, Helicobacter pylori (H. pylori) infection, a well known cause of gastric ulcer, has been associated, via molecular mimicry of host structures by its constituents with the same autoimmune conditions, also characterized by fibrotic changes and/or lymphoplasmacytic inflammations, accompanied by aberrations of T cell apoptosis that contribute to hepatobiliary- or extrahepatic-tissue destruction. Considering that H. pylori is involved in the pathogenesis and pathophysiology of these autoimmune disorders, we propose that this organism might trigger autoimmune pancreatitis through induction of autoimmunity and apoptosis.