Prevalence and significance of anticardiolipin, anti-beta2 glycoprotein I and anti-prothrombin antibodies in chronic hepatitis C

NETs in APS: Current Knowledge and Future Perspectives

PURPOSE OF REVIEW

Antiphospholipid syndrome (APS) is a thrombo-inflammatory disease that is primarily treated with anticoagulation. Better understanding the inflammatory aspects of APS could lead to safer, more effective, and more personalized therapeutic options. To this end, we sought to understand recent literature related to the role of neutrophils and, in particular, neutrophil extracellular traps (NETs) in APS.

RECENT FINDINGS

Expression of genes associated with type I interferons, endothelial adhesion, and pregnancy regulation are increased in APS neutrophils. APS neutrophils have a reduced threshold for NET release, which likely potentiates thrombotic events and perhaps especially large-vein thrombosis. Neutrophil-derived reactive oxygen species also appear to play a role in APS pathogenesis. There are new approaches for preventing and disrupting NETs that could potentially be leveraged to reduce the risk of APS-associated thrombosis. Neutrophils and NETs contribute to APS pathophysiology. More precisely understanding their roles at a mechanistic level should help identify new therapeutic targets for inhibiting NET formation, enhancing NET dissolution, and altering neutrophil adhesion. Such approaches may ultimately lead to better clinical management of APS patients and thereby reduce the chronic burden of this disease.

Neutrophils-Important Communicators in Systemic Lupus Erythematosus and Antiphospholipid Syndrome

Systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) are two autoimmune diseases that can occur together or separately. Insights into the pathogenesis have revealed similarities, such as development of autoantibodies targeting subcellular antigens as well as a shared increased risk of cardiovascular morbidity, potentially due to mutual pathologic mechanisms. In this review, we will address the evidence implicating neutrophils in the pathogenesis of these conditions, highlighting their shared features. The neutrophil is the most abundant leukocyte, recognized for its role in infectious and inflammatory diseases, but dysregulation of neutrophil effector functions, including phagocytosis, oxidative burst and formation of neutrophil extracellular traps (NETs) may also contribute to an autoimmune process. The phenotype of neutrophils in SLE and APS differs from neutrophils of healthy individuals, where neutrophils in SLE and APS are activated and prone to aggregate. A specific subset of low-density neutrophils with different function compared to normal-density neutrophils can also be found within the peripheral blood mononuclear cell (PBMC) fraction after density gradient centrifugation of whole blood. Neutrophil phagocytosis is required for regular clearance of cell remnants and nuclear material. Reactive oxygen species (ROS) released by neutrophils during oxidative burst are important for immune suppression and impairment of ROS production is seen in SLE. NETs mediate pathology in both SLE and APS via several mechanisms, including exposure of autoantigens, priming of T-cells and activation of autoreactive B-cells. NETs are also involved in cardiovascular events by forming a pro-thrombotic scaffolding surface. Lastly, neutrophils communicate with other cells by producing cytokines, such as Interferon (IFN) -α, and via direct cell-cell contact. Physiological neutrophil effector functions are necessary to prevent autoimmunity, but in SLE and APS these are altered.

Risk of developing antiphospholipid antibodies following viral infection: a systematic review and meta-analysis

Objective The objective of this paper is to conduct a systematic review and meta-analysis on the risk of developing elevated antiphospholipid (aPL) antibodies and related thromboembolic and/or pregnancy events following a viral infection. Method We searched Medline, EMBASE, Web of Science, PubMed ePubs, and Cochrane Central Register of Controlled Trials through June 2016. Independent observational studies of elevated aPL antibodies in patients with a viral infection compared with controls or patients with lupus were included. Results We analyzed 73 publications for 60 studies. Human immunodeficiency virus (HIV) and hepatitis C virus (HCV) were most commonly reported. Compared with healthy controls, patients with HIV were more likely to develop elevated anticardiolipin (aCL) antibodies (risk ratio (RR) 10.5, 95% confidence interval (CI) 5.6-19.4), as were those with HCV (RR 6.3, 95% CI 3.9-10.1), hepatitis B virus (HBV) (RR 4.2, 95% CI 1.8-9.5), and Epstein-Barr virus (EBV) (RR 10.9 95% CI 5.4-22.2). The only statistically significant increased risk for anti-β2-glycoprotein I (anti-β2-GPI) antibodies was observed in patients with HCV (RR 4.8 95% CI 1.0-22.3). Compared with patients with lupus, patients with HIV were more likely to develop elevated aCL antibodies (RR 1.8, 95% CI 1.3-2.6), and those with EBV, elevated anti-β2-GPI antibodies (RR 2.2, 95% CI 1.3-3.9). Thromboembolic events were most prevalent in patients with elevated aPL antibodies who had HCV (9.1%, 95% CI 3.0-18.1), and HBV (5.9%, 95% CI 2.0-11.9) infections, and pregnancy events were most prevalent in those with parvovirus B19 (16.3%, 95% CI 0.78-45.7). However, compared to virus-infected patients with negative aPL antibodies, the only statistically significant increased risk was observed in those with HCV and positive aPL. Conclusions Viral infection can increase the risk of developing elevated aPL antibodies and associated thromboembolic events. Results are contingent on the reported information.

A unique antiphospholipid assay recognizing phospholipid mixture compared with criteria antiphospholipid immunoassays in lupus patients

Background While essential for the classification of antiphospholipid syndrome (APS), anticardiolipin (aCL) assays lack specificity and anti-β2glycoproteinI (anti-β2GPI) assays lack sensitivity in this regard. Our aim was to perform a comparative analysis of the APhL ELISA assay (IgG/IgM) and criteria antiphospholipid (aPL) immunoassays in identifying APS-related clinical manifestations in a large group of patients with systemic lupus erythematosus (SLE). Methods Serum samples from 1178 patients from the Hopkins ( n = 543), LUMINA ( n = 588) and Jamaican SLE cohorts ( n = 47) were examined for IgG/IgM positivity in aCL (in-house), anti-β2GPI (two commercial kits) and APhL (Louisville APL) ELISA assays. Correlation of assay positivity with clinical manifestations and sensitivity, specificity, positive and negative predictive values and likelihood ratios were evaluated. A case series analysis was also performed in patients for whom there was isolated positivity in the specific aPL assays. Results The prevalence of aCL positivity was 34.9%, anti-β2GPI kit A was 22.6%, APhL was 11.5% and anti-β2GPI kit B was 7.6% in the study population. Anti-β2GPI kit B, aCL and APhL assays were correlated with venous thrombosis, while only APhL was significantly correlated with arterial thrombosis and consistently correlated with pregnancy-related morbidity. No significant correlations were noted for anti-β2GPI kit A. Sensitivity was greatest for aCL assays followed by anti-β2GPI kit A, APhL and anti-β2GPI kit B, while specificity was greatest and equal for anti-β2GPI kit B and APhL assays. Conclusions Overall, APhL antibodies, especially IgG, represent a promising biomarker for the classification of APS patients in the context of autoimmunity and in risk assessment with regards to pregnancy morbidity and thrombotic manifestations.

Late-Onset Immune Thrombocytopenic Purpura After Withdrawal of Interferon Treatment for Chronic Hepatitis C Infection: A Case Report

Immune thrombocytopenic purpura (ITP) is a life-threatening complication following pegylated interferon alpha (PEG-IFN) plus ribavirin treatment, the standard treatment for hepatitis C virus (HCV) infection. We reported a rare case with late-onset ITP after withdrawal of PEG-IFN treatment.A 53-year-old male with hepatitis C developed massive gum bleeding and a severe, reversible, immune thrombocytopenia 2 weeks after cessation of PEG-IFN treatment for HCV due to anemia and depression. The platelet count decreased to 4000 cells/μL. The HCV viral load was undetectable at the end of PEG-IFN treatment and during follow-up for 5 months. Other potential autoimmune disorders were ruled out. Late-onset ITP associated with PEG-IFN treatment was diagnosed.The patient was treated successfully with steroid and azathioprine. Platelet count gradually increased to 117 × 10 cells/μL on the 18th day after admission.ITP is a rare complication in patients with hepatitis C or in patients who received PEG-IFN treatment. The particular case supported that it may occur even after withdrawal of PEG-IFN treatment. Physicians should be aware of this late-onset complication.

Viral hepatitis and anti-phospholipid antibodies positivity: A systematic review and meta-analysis

BACKGROUND

Anti-phospholipid antibodies positivity is associated with several clinical conditions, including infectious diseases.

AIMS

We performed a meta-analysis evaluating the association of hepatitis B and C with anti-phospholipid antibody positivity and with anti-phospholipid antibody-related thrombotic complications.

METHODS

Studies evaluating the association of viral hepatitis with anti-cardiolipin, anti-β2 glycoprotein-I and lupus anticoagulant antibodies and anti-phospholipid antibody-related thrombotic events were systematically searched.

RESULTS

20 studies (2319 cases, 1901 controls) were included. The analyses showed that viral hepatitis is associated with the presence of anti-cardiolipin and anti-β2 glycoprotein-I antibodies. The association with anticardiolipin antibodies was confirmed in both hepatitis B (OR 11.22, 95% CI: 6.68-18.84) and hepatitis C (OR 11.26, 95% CI: 6.82-18.59). Similarly, compared to controls, anti-β2 glycoprotein-I antibodies were found more frequently in hepatitis B (OR 14.07, 95% CI: 3.06-64.66) and hepatitis C (OR 5.64, 95% CI: 1.69-18.77). Moreover, 11 studies (257 cases, 1079 controls) showed a higher prevalence of venous and/or arterial thrombosis in patients with hepatitis and anti-cardiolipin antibody positivity compared hepatitis alone (OR 3.29, 95% CI: 1.79-6.07). This result was consistently confirmed in hepatitis C (OR 3.64, 95% CI: 1.78-7.46) but not in hepatitis B.

CONCLUSIONS

Viral hepatitis is significantly associated with anti-phospholipid antibody positivity and with anti-phospholipid antibody-related thrombotic complications.

Clinical relevance of antibodies to cardiolipin in patients with chronic hepatitis C

The significance of antibodies to cardiolipin (anti-CL) remains uncertain in patients with chronic hepatitis C (CH-C). The main purpose of this study was to elucidate the clinical characteristics of patients with CH-C seropositive for anti-CL. The prevalence of anti-CL and clinical parameters associated with anti-CL in those patients were examined. Six of the 45 (13%) patients with CH-C had anti-CL. However, none of these six CH-C patients fulfilled the criteria for antiphospholipid syndrome. Serum triglyceride and apolipoprotein B (ApoB) levels in CH-C patients with anti-CL were significantly higher than those in CH-C patients without anti-CL. Serum triglyceride levels positively correlated with serum ApoB levels. CH-C patients with anti-CL had significantly more progressive hepatic fibrosis than those without anti-CL. The degree of 8-hydroxy 2'-deoxyguanosine (8-OHdG) expression in the liver tissue was more severe in CH-C patients with anti-CL than in those without it. However, the emergence of anti-CL in CH-C patients was independent of insulin resistance, hepatic steatosis, and iron overload. These findings suggest that the emergence of anti-CL is associated with oxidative stress and that CH-C patients seropositive for anti-CL have clinical characteristics of hypertriglyceridemia, which derives from the facilitation of ApoB synthesis, and progressive hepatic fibrosis.

Hepatitis C virus and autoimmunity

Hepatitis C virus infection is associated with several extrahepatic manifestations. About 60% of patients infected with HCV develop at least one extrahepatic manifestation. The majority of these diseases seem to be triggered through autoimmune mechanisms, such as autoantibody production, autoreactive T cells and complex autoimmune mechanisms leading to systemic autoimmune disorders. In this review we categorize these diseases into three groups according to the main pathogenetic process involved, in particular B-cell-mediated, T-cell-mediated and complex autoimmune systemic diseases.

Antiphospholipid syndrome during pegylated interferon alpha-2a therapy for chronic hepatitis C

A great variety of autoimmune side effects have been reported during interferon alpha therapy. The presence of anticardiolipin antibodies during interferon alpha therapy in chronic hepatitis C has also been reported. There are no reports on the occurrence of antiphospholipid syndrome in patients with chronic hepatitis C while on pegylated interferon alpha therapy. We report a case of a 46-year-old man who developed antiphospholipid syndrome 12 weeks after starting pegylated interferon alpha plus ribavirin for chronic hepatitis C. The clinical presentation of antiphospholipid syndrome was primary adrenal insufficiency secondary to bilateral adrenal haematoma and subclavian vein thrombosis. A pathogenic role of pegylated interferon alpha as a trigger factor for antiphospholipid syndrome development is suggested.

[Antiphospholipid antibodies, antiphospholipid syndrome and viral infections]

Since the association between antiphospholipid antibodies and syphilis was first described, many other viral, bacterial and parasitic infections have been shown to induce antiphospholipid antibodies, notably anticardiolipin antibodies. These aPL are usually associated neither with anti-beta2 glycoprotein I antibodies (anti-beta2-GPI) nor with thrombotic events, even if cases of arterial and deep venous thrombosis have been reported in such circumstances. A literature review shows that anticardiolipin antibodies occur frequently in viral infections, particularly in HIV (49.8%), HBV (24%) and HCV (20%). The prevalence of anti-beta2 glycoprotein I antibodies (anti-beta2GPI) is lower (HCV: 1.7%, HIV: 5.6%, HBV: 3.3%) and there is no demonstrated association with a risk of thrombotic events or hematological manifestations defining antiphospholipid syndrome (APS). Regarding other viral infections, including viral hepatitis A, herpes virus (CMV, EBV, VZV), parvovirus B19 and HTLV-1 infections, only a few studies are available but data confirm the high prevalence of antiphospholipid antibodies at the acute phase. Finally, antiphospholipid antibodies, mainly anticardiolipin, are frequently associated with viral infections. Their presence may probably reflect an intense or chronic antigenic stimulation of the immune system. However, their evolution under antiviral therapy and correlation with the quality of the virological control and/or the immune restoration remain to be determined.

A protocol for determination of anticardiolipin antibodies by ELISA

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

Antiphospholipid antibodies and hepatitis C virus infection in Iranian thalassemia major patients

Although the precise nature of Antiphospholipid antibodies is still not clearly defined, they are known to have association with thromboembolic events and have been found in hepatitis C virus (HCV) infection. Moreover, high prevalence of HCV infection and thrombotic risk is described in thalassemia. We aimed at investigating the prevalence of anticardiolipin antibodies (aCLAbs), lupus anticoagulant (LA), and their relation with HCV infection in Iranian thalassemic patients. Presence of anti-HCV antibody, serum HCV-RNA, aCLAbs, and LA activity was determined in 131 patients with thalassemia major (male/female: 63/68 aged 3-29 years) registered at thalassemia unit, Dastgheib Hospital, Shiraz, Iran. Sixty-one healthy controls were also included. Anti-HCV antibody was positive in 24 (18.3%), IgG aCLAbs in 56 (42.7%), and LA activity in 9 (6.9%) patients. 87.5% of patients positive for aCLAbs had a low titer of aCLAbs. Although none of the participants had a previous history of thrombosis, higher prevalence of aCLAbs was detected in thalassemic patients compared with controls. No significant difference in the prevalence of aCLAbs was found between HCV-infected and noninfected patients. A high prevalence of aCLAbs, the majority in low titers, was detected in Iranian thalassemic patients irrespective of previous history of thrombosis and presence of HCV infection.

Antiphospholipid syndromes in infectious diseases

Antiphospholipid antibodies are essential in the diagnosis of antiphospholipid syndrome (APS), or the classic "Hughes syndrome," which is a systemic disorder that is autoimmune in nature. They are also found in various infections in low titers without any evidence of thrombotic manifestations of APS. However, in a few infections, when antiphospholipid antibodies are associated with protein cofactor, there can be associated thrombosis. Different infections are also responsible for triggering a subset of lethal APS, acute catastrophic APS. This situation requires prompt diagnosis and aggressive treatment of the infection to prevent severe complications.

Autoantibodies in nonautoimmune individuals during infections

Infections can act as environmental triggers inducing or promoting autoimmune disease in genetically predisposed individuals. Identification of microbial peptides similar to self-tissues may by molecular mimicry, provide the inducing mechanism for an immune response. The aim of this study was to identify autoantibodies (autoAbs) in nonautoimmune individuals during acute bacterial, viral, or parasitic infections. Specific Abs or specific infections with an increased autoAb load may shed insight into the mechanisms of autoimmune disease. Sera from 88 patients with acute infections (41 bacterial, 23 viral, 17 parasitic, and 7 rickettsial) were tested by the ELISA method for antinuclear antibodies (ANA) 8 Pro, and Abs to thyroid peroxidase (TPO), thyroglobulin, phospholipids, annexin-V, laminin, anti-Saccharomyces cervisiae (ASCA), and prothrombin, along with 80 normal controls. Elevated titers of Abs to annexin-V and prothrombin were the most prevalent in viral, parasitic, and rickettsial infections and to laminin in viral and parasitic infections. Elevated titers of ASCA and ANA were found in viral and bacterial infections. Antiphospholipid Abs were found in parasitic and Q-fever infections. Thirty-four individuals harbored elevated titers of at least two Abs. An autoAb burden was detected in individuals with hepatitis A, hepatitis B, toxoplasma or Q-fever infections. In nonautoimmune individuals with various (bacterial, viral, parasitic, and rickettsial) infections, elevated titers of Abs to annexin-V, prothrombin, laminin, ASCA, ANA, and phospholipids were most frequently detected.

Antiphospholipid antibodies, antiphospholipid syndrome and infections

Since the association between antiphospholipid antibodies (aPL) and syphilis was first described, many other viral, bacterial and parasitic infections have been shown to induce antiphospholipid antibodies, notably anticardiolipin antibodies (aCL). A review of the literature shows that while aCL occur frequently in viral infections, particularly in HIV (49.75%), HBV (24%) and HCV (20%), it is very rarely associated with anti-beta2 glycoprotein I antibodies (anti-beta2GPI) and is not correlated with thrombosis risk or hematological manifestations of the antiphospholipid syndrome (APS). Concerning bacterial infections, aCL is often present in leprosy (42.7%), where it is frequently associated with the presence of anti-beta2GPI (44.8%), and in syphilis infections (8 to 67%), though without correlation with thrombotic events. Though few individual patients with unequivocal infection-induced aPL satisfy criteria for APS, the lack of statistical association with thrombotic events strongly argues against the identification of a true APS subset in this context. However, physicians should keep in mind the fact that an infection, generally bacterial, in patients with confirmed APS, may lead to catastrophic antiphospholipid syndrome with a possible fatal outcome.

Isolated digital gangrene complicating hepatitis a infection in a child

Hepatitis A virus is rarely associated with extrahepatic complications. A child presented with a history suggesting Raynaud's phenomenon and severe digital gangrene, as a complication of hepatitis A infection. Coagulation study results (protein C, protein S, antithrombin III, and activated protein C resistance) were all normal except for anticardiolipin antibodies, which were present on initial presentation and resolved later. Antinuclear antibodies, rheumatoid factor, lupus anticoagulant, antineutrophilic cytoplasmic antibodies, and Venereal Disease Research Laboratory test were all negative. Cryoglobulins were not detected. C3 and C4 levels were normal. Blood urea nitrogen and creatinine levels were normal as well. The patient was treated with aspirin and diclofenac, and improved slowly with complete resolution of gangrene and symptoms after 3 months. She remains asymptomatic 4 years later. Transient antiphospholipid syndrome or isolated Raynaud's phenomenon may be added to the list of extrahepatic complications of hepatitis A.

Fine specificity of antibodies against phospholipids and beta-2-glycoprotein I in monoclonal gammopathy associated neuropathies

Phospholipids are abundantly represented within the nervous system. Aim of our study was to evaluate the presence and fine specificity of anti phospholipid antibodies (aPLAb) among patients with monoclonal gammopathy associated neuropathy. Thirty nine percent of these patients had high titers of aPLAb, mostly associated with low levels of anti beta2 glycoprotein I, which suggests different antibody specificity compared to patients with anti phospholipid syndrome. Further 6/48 patients with dysimmune neuropathy without monoclonal gammopathy had positive aPLAb titers. APLAb strongly cross-reacted with sulfatide. These findings suggest an adjuntive role of aPLAb on nerve damage and may help to better understand the nerve binding properties of anti-sulfatide antibodies.

Accidents vasculaires cérébraux révélant un syndrome catastrophique des anti-phospholipides associé à une hépatite virale C

INTRODUCTION

Very little cases of antiphospholipid syndrome (APLS) have been described among patients having chronic hepatitis C virus infection (HCV).

CASE REPORT

We report the observation of a 43-year-old woman who presented APLS diagnosed following recurrent strokes. Etiological investigations concluded on an association of APLS with HCV infection.

DISCUSSION

Besides being exceptional, this association raises certain etiopathogenic problems. Indeed while antiphospholipid antibodies (aPL) are frequently noted during chronic hepatitis C, they rarely generate thromboembolic complications.

A re-appraisal of the normal cut-off assignment for anticardiolipin IgM tests

BACKGROUND

Recent reports show an apparent large number of individuals with low to moderate titers of anticardiolipin antibodies (ACA), particularly of the IgM isotype with no clinical signs of antiphospholipid syndrome (APS). The significance of these results is unknown. This study examined the prevalence of low positive titers of IgM ACA antibodies in a large number (n = 982) of normal blood donors (Group 1) and in a group of 159 individuals > 60 years of age (Group 2). The effect of re-defining the currently used cut-off values for the IgM ACA tests was also examined.

METHODS

IgM ACA antibodies were tested in three ELISA assays: the Bindazyme Anti-IgM Cardiolipin EIA kit (assay A), an 'in-house' ACA test (assay B), and the APhL ELISA kit (assay C).

RESULTS

THE normal range cut-offs were re-calculated using the 95th percentile of the data for Group 1 (12.4 MPL U mL(-1) for assay A, 5.4 MPL U mL(-1) for assay B and 9.5 MPL U mL(-1) for assay C) and Group 2 (9.9 MPL U mL(-1) for assay A, 5.5 MPL U mL(-1) for assay B and 13.2 MPL U mL(-1) for assay C). These values were not significantly different from the current cut-off values for each assay. The prevalence of low positive results in Group 1 relative to the re-defined cut-off for that group were: 1.0%, 1.1% and 0.9% in assay A, B and C; and in Group 2: 0.6%, 0.6% and 0.6%, respectively. An indeterminate zone (between the 95th and 99th percentile) was then established for the two groups. The prevalence in Group 1 was 3.8%, 3.9% and 3.9% for assays A, B and C, respectively, and for Group 2: 4.4% in all three assays.

CONCLUSIONS

The data confirm that the current cut-off point for each of the three assays is correct. We suggest based on this study that the low positive range is re-assigned 'indeterminate' and recommend that samples falling in this category should be retested to confirm positivity at a later date.

Antiphospholipid antibodies may be a new prognostic parameter in aggressive non-Hodgkin's lymphoma

OBJECTIVES

Patients with malignancies have an increased prevalence of antiphospholipid antibodies (APA). The aim of this study was to determine the prevalence of IgG, IgM, and IgA anticardiolipin antibodies (aCL) and anti-beta-2 glycoprotein I antibodies (anti-beta2-GPI) in patients with non-Hodgkin's lymphoma (NHL), and to investigate their clinical and prognostic significance.

METHODS

The study group included 86 patients with NHL. Enzyme-linked immunosorbent assay kits were used to measure the concentrations of aCL and anti-beta2-GPI, and coagulation tests, to measure lupus anticoagulant (LAC) activity. Blood was collected at diagnosis in all patients and at follow-up in 15. Median follow-up time was 1.9 yr.

RESULTS

Elevated APA levels were found in 35 patients (41%) at diagnosis: one patient aCL IgG, five patients aCL IgM, five aCL IgA, one anti-beta2-GPI IgG, 14 anti-beta2-GPI IgM, and 19 anti-beta2-GPI IgA; LAC activity was found in three of 67 patients (4.5%). There was no significant correlation between elevated APA levels and patient's age or sex, disease stage or grade, bone marrow involvement, B symptoms, serum lactate dehydrogenase levels, serum beta2 microglobulin levels, International Prognostic Index (IPI) score, performance status, type of treatment, or response to treatment. There was a correlation between elevated APA and absence of extranodal disease (P = 0.045). A strong negative correlation was found between elevated APA at diagnosis and survival time. Two-year survival was 90 +/- 5% for patients without APA at diagnosis compared with 63 +/- 11% for patients with an elevated APA levels (P = 0.0025). APA added to the predictive value of IPI for event-free and overall survival.

CONCLUSIONS

APA are elevated in 41% of NHL patients at diagnosis and are correlated with shortened survival. Their level may serve as an independent prognostic variable in aggressive NHL.

An IL-7 fusion protein that shows increased thymopoietic ability

The role of IL-7 during thymopoiesis has led to it being the focus of a number of therapeutic interventions. However, its small size and pleiotropic nature present problems for thymus-directed therapies. We have created a fusion molecule between the extracellular N-terminal domain of CCR9 and IL-7, which has the potential to overcome these difficulties. This novel fusion protein retains the thymopoietic activity of IL-7 and the ligand-binding ability of CCR9. As a thymopoietic agent, compared with IL-7, it shows an enhanced retention in the thymus, increased de novo T cell production, and increased thymic output. Old mice receiving the fusion protein show improved CD8 T cell responses and reduced viral load after infection with influenza virus compared with those receiving IL-7. This chimeric molecule offers a novel therapeutic strategy that may result in the production of an effective immunorestorative agent.

Improvement of thrombocytopenia with disappearance of HCV RNA in patients treated by interferon-alpha therapy: possible etiology of HCV-associated immune thrombocytopenia

We evaluated the relationship between the severity of thrombocytopenia and the serum hepatitis C virus (HCV) RNA level to investigate the mechanism of thrombocytopenia in patients with HCV infection. Patients who had chronic hepatitis without splenomegaly were divided into two groups according to the platelet count, which were 18 patients with a platelet count < or =150 x 10(9)/L and 22 patients with a platelet count >150 x 10(9)/L. HCV RNA, platelet-associated immunoglobulin G (PAIgG), rheumatoid factor (RF), and other immunological parameters were measured and correlations were investigated. Patients in the low platelet group had higher levels of PAIgG, Th1 cells, thrombopoietin (TPO), and RF than those in the normal platelet group (textitP < 0.05). Twenty-two patients completed 6 months of IFN therapy and were followed for more than 1 yr afterwards. Twelve patients who responded to IFN therapy with clearance of HCV showed an increase of the platelet count, whereas the 10 patients who did not respond to IFN showed a decrease of the platelet count. The improvement of thrombocytopenia after interferon therapy suggests a contribution of HCV infection to this condition.

Hepatitis C virus-related thrombocytopenia: clinical and laboratory characteristics compared with chronic immune thrombocytopenic purpura

Thrombocytopenia can be a complication of hepatitis C viral (HCV) infection. However, there is little published data regarding the clinical and laboratory manifestations of HCV-related thrombocytopenia (HCV-TP) compared with adult chronic immune thrombocytopenic purpura (CITP). We reviewed the medical records for all patients evaluated for chronic thrombocytopenia by the Haematology Service between January 1996 and June 2000. All patients were screened for HCV infection at the time of initial diagnosis. Of 250 patients who fulfilled American Society of Hematology criteria for CITP, 76 (30%) were HCV seropositive. HCV-TP patients were older [mean age (+/-SD) 54.9 +/- 8 years vs. 40.3 +/- 8 years, P </= 0.001] and equally distributed between both sexes. HCV-TP patients had less severe thrombocytopenia, defined as platelet count </=10 x 10(9)/l (4% vs. 46% for CITP, P </= 0.001). However, 56 (74%) had a platelet count </=50 x 10(9)/l. Symptoms and signs of thrombocytopenia were less frequent in HCV-TP, but major bleeding was more frequent (25% vs. 10%, P = 0.0059). Serum cryoglobulins and anticardiolipin antibodies were more frequent in HCV-TP (90% and 62% respectively), but rare in CITP (7% and 15%, P </= 0.001 compared with HCV-TP). HCV infection can be associated with significant thrombocytopenia and appears to be a distinct clinical entity.

Combination therapy with pegylated interferon plus ribavirin in the treatment of hepatitis C virus-related thrombocytopenia

BACKGROUND

Isolated thrombocytopenia is a common manifestation of hepatitis C virus (HCV) infection. There is no established treatment modality for this condition. The efficacy of standard interferon (IFN) monotherapy has been reported in some studies. The major disadvantage of this treatment is the high rate of recurrence due to viral breakthrough during the first 12 weeks of treatment. Pegylated IFNs are now the standard regimen for chronic hepatic disease due to HCV infection. However, due to a lack of evidence, pegylated IFNs are not widely used for HCV-related isolated thrombocytopenia.

OBJECTIVE

The aim of this report was to present the case of a male patientwith severe symptomatic thrombocytopenia due to HCV infection.

METHODS

Thrombocytopenia was treated with pegylated IFN plus ribavirin.

RESULTS

Although standard IFN monotherapy failed to achieve virologic and hematologic improvement, therapy with pegylated IFN alfa-2a plus ribavirin was associated with both virologic and hematologic improvement without any significant adverse effects.

CONCLUSIONS

Pegylated IFN plus ribavirin was effective in this patient for thetreatment of HCV-related thrombocytopenia. However, further research is needed to define the response rate in different patient populations.

Prevalence of antiphospholipid and antiplatelet antibodies in human immunodeficiency virus (HIV)-infected Chilean patients

Antiphospholipid (aPL) and antiplatelet (aPlt) antibodies, found in patients with autoimmune diseases, are also detected in infectious diseases. The purpose of this study was to examine the prevalence of these antibodies in HIV patients and to evaluate an association of these antibodies with thrombocytopenia and/or thrombosis. Sixty-three HIV-seropositive patients and 52 normal controls were studied. Anti-cardiolipin (aCL), anti-beta(2) glycoprotein I (anti-beta(2)GPI), and antiprothrombin (aPT) antibodies were determined and the lupus anticoagulant (LA) test was performed. Antiplatelet antibodies (aPlt) were also determined. Seven out of 63 (12.7%) HIV patients were positive for aCL, four of 63 (6.3%) for anti-beta(2)GPI, and five of 63 (7.9%) for aPT. No patients studied were LA positive. Six out of 63 (9.5%) patients were positive for aPlt. One of them showed weak reactivity for GPIb-IX. The platelet count of patients (202+/-63 x 10(3) platelets/microL) was significantly lower than in the controls (343+/-6 x 10(3) platelets/microL) (P<0.001). There was no correlation between the presence of aPL and/or aPlt and thrombocytopenia. Of the HIV-infected patients, 22.2% presented aPL and 9.4% aPlt antibodies. In this study, the presence of aPL and aPlt antibodies was not associated with the development of thrombosis and/or thrombocytopenia.

Anticardiolipin, anti-beta(2)-glycoprotein I and antiprothrombin antibodies in black South African patients with infectious disease

OBJECTIVES

To investigate IgG, IgM, and IgA, antiphospholipid antibodies (aPL), against cardiolipin (aCL), beta(2)-glycoprotein I (anti-beta(2)GPI), and prothrombin (anti-PT), in black South African patients with infectious disease. Unlike patients with systemic lupus erythematosus (SLE) and the antiphospholipid syndrome (APS), raised levels of aPL in infectious diseases are not usually associated with thrombotic complications.

PATIENTS AND METHODS

Serum samples from 272 patients with a variety of infectious diseases (100 HIV positive, 112 leprosy, 25 syphilis, 25 malaria, and 10 HCV patients) were studied and compared with autoantibody levels in 100 normal controls. All three aPL were measured using commercial enzyme linked immunosorbent assay (ELISA) kits.

RESULTS

Raised levels of all three aPL were found in all patient groups studied: aCL in 7%, anti-beta(2)GPI in 6%, and aPT in 43% of 100 HIV patients, in 29%, 89%, and 21% of 112 patients with leprosy, in 8%, 8%, and 28% of 25 patients with syphilis, in 12%, 8%, and 28% of 25 patients with malaria, and in 20%, 30%, and 30% of 10 HCV patients studied, respectively.

CONCLUSIONS

The prevalence of aCL and anti-beta(2)GPI in black South African HIV positive patients, or those with syphilis, malaria, or hepatitis C virus is lower than reported for mixed race or white populations. aPT were the most prevalent aPL detected in these patient groups, except in patients with leprosy, for whom anti-beta(2)GPI was the most prevalent, and where the spectrum of aPL was similar to that seen in patients with SLE and APS.

Anticardiolipin antibodies in chronic viral hepatitis. Do they have clinical consequences?

Antiphospholipid antibodies are a heterogeneous group of acquired autoantibodies that react with anionic phospholipids, such as cardiolipin. Anticardiolipin antibodies (ACAs) are frequently found in patients with systemic lupus erythematosus and other autoimmune disorders and can react with the phospholipid alone or bound to the cofactor beta2-glycoprotein-I. This latter form of cofactor-dependent ACAs is strongly associated with the occurrence of thrombotic events. ACAs have been observed to occur in both chronic hepatitis B and chronic hepatitis C as well as in other viral infections and in neoplastic diseases. In viral infection, ACAs are generally cofactor independent and may represent an epiphenomenon of the infection. Some studies, however, have found an increased incidence of thrombotic disorders in patients with chronic hepatitis C virus (HCV) who manifest ACA positivity suggesting that the presence of these autoantibodies may predispose to thrombosis in specific HCV-infected patients. In conclusion, ACAs are commonly found in patients with chronic viral infection but their pathogenetic role and the mechanisms that stimulate their production have not yet been clarified.

Anti-cardiolipin antibodies in patients with chronic viral hepatitis are independent of beta2-glycoprotein I cofactor or features of antiphospholipid syndrome

BACKGROUND

Although controversial, some authorities have implicated hepatitis C virus (HCV) as a cause of anti-phospholipid syndrome (APLS). Anti-cardiolipin antibodies (anti-CLAbs) in APLS are cofactor-dependent ('pathogenic' antibodies). We conducted a study in order to determine the prevalence of anti-CLAbs in HCV patients, and furthermore to address whether these autoantibodies are cofactor-dependent or not and whether they are associated with features of APLS. Patients with hepatitis B virus (HBV) were also evaluated in order to assess whether there are differences in the prevalence and the clinical significance of anti-CLAbs between these two major types of chronic viral hepatitis.

MATERIALS AND METHODS

One hundred and seventy-four consecutive HCV patients, 50 HBV patients and 267 healthy were investigated for the presence of anti-CLAbs and antibodies against beta2-glycoprotein I (beta2-GPI), which is the most important cofactor of the 'pathogenic' anti-CLAbs in APLS. IgG anti-CLAbs were determined by an in-house quantitative ELISA and anti-beta2-GPIAbs using a commercial ELISA kit.

RESULTS

21.3% of the HCV and 14% of the HBV patients tested positive for IgG anti-CLAbs (P < 0.0001 compared with healthy controls). Neither age, sex, certain epidemiologic and laboratory parameters nor the clinical status and the histologic findings were associated with anti-CLAbs detection in both diseases. 2.3% of the HCV (P < 0.05 compared with healthy controls) and 2% of the HBV patients tested positive for anti-beta2-GPIAbs. Presence of anti-CLAbs was not associated with features of APLS.

CONCLUSIONS

A significant proportion of the HCV and HBV patients had detectable IgG anti-CLAbs. However, the anti-CLAbs titres were relatively low, and in most cases seem to be cofactor-independent ('nonpathogenic'). The latter is further supported by the lack of their association with clinical features of APLS. Furthermore, anti-CLAbs appear to be detected irrespective of the demographic, laboratory, clinical and histologic status in both HCV and HBV. However, prospective studies of longer duration may be required in order to address whether anti-CLAbs in patients with chronic viral hepatitis are or are not of clinical importance.

Antiphospholipid antibodies after surgical exposure to topical bovine thrombin

Exposure to topical bovine thrombin during surgery frequently results in the development of antibodies to multiple protein and carbohydrate antigens. We investigated the frequency of increased levels of antibodies to cardiolipin and beta(2)-glycoprotein I (beta(2)-GPI) in two groups of patients, one exposed to bovine thrombin during cardiovascular surgery (n = 151) and a "control" group undergoing cardiovascular surgery but without exposure to bovine thrombin (n = 11). Anticardiolipin antibody levels were increased before surgery in 10 of the 151 patients exposed to topical thrombin (6.6%). Four to 8 weeks after surgery, 84 patients (55.6%) had increased anticardiolipin antibody levels (P <.0001). In the control group, an increased anticardiolipin antibody level was present in a single patient before and after surgery (9%). Increased levels of antibodies to bovine and human beta(2)-GPI were also observed after surgery in the patients exposed to topical thrombin (37.7% and 38.2%, respectively). Increased anticardiolipin levels correlated with higher levels of antibody to bovine, but not human, beta(2)-GPI. In addition, increased levels of anticardiolipin antibody were associated with higher levels of antibodies to bovine factor V and prothrombin, as well as human factor V. Antibody binding on an enzyme-linked immunosorbent assay conducted to detect anticardiolipin antibody was dependent on the presence of anionic phospholipid, indicating that binding was not linked to the fetal bovine serum in the blocking buffer alone. Seven of 8 patients with delayed thromboembolic complications had increased anticardiolipin IgG antibody levels after surgery, but this association was not statistically significant. Nevertheless, our findings support the recommendation that the clinical safety of these commonly used hemostatic agents should be reassessed.

Viral infections and antiphospholipid antibodies

OBJECTIVE

To study the relationship between viral infections and the induction of antiphospholipid (aPL) antibodies.

METHODS

We reviewed the medical literature from 1968 until 2000 using MEDLINE and the key words virus, infection, antiphospholipid, and anticardiolipin.

RESULTS

Anticardiolipin antibodies and/or lupus anticoagulant were associated with a number of viral infections, including hepatitis C virus, human immunodeficiency virus, cytomegalovirus, varicella zoster, Epstein-Barr virus, adenovirus, and parvovirus B. In many instances, the presence of these antibodies was associated with thrombosis.

CONCLUSION

The clinical significance of finding aPL antibodies in patients with viral infections remains unknown. In some patients, these antibodies may be transient and disappear within 2 or 3 months. In other susceptible individuals, they may persist and raise the question of whether infections may trigger the development of aPL antibodies in autoimmune diseases.

Treatment of hepatitis C related thrombocytopenia with interferon alpha

Thrombocytopenia is a common extrahepatic manifestation of hepatitis C (HCV) infection. Treatment with steroids may be effective, but can exacerbate the viral infection. Interferon alpha (INF) has documented efficacy in the treatment of HCV, but its use in the treatment of HCV thrombocytopenia is controversial. We treated eight patients with HCV-related thrombocytopenia, who had platelet counts of fewer than 50 x 10(9)/l (range: 16 to 46 x 10(9)/L) with INF 3 MU SQ three times a week. Planned duration of treatment was 24 weeks. Five patients had no evidence of hepatic cirrhosis, three had cirrhosis, and two had palpable splenomegaly. Only three patients tolerated the full course of treatment, and all three had improvement in their platelet counts to greater than 50 x 10(9)/l. Two other patients had improvement in platelet counts to more than 50 x 10(9)/l with shorter duration of treatment (six and 16 weeks, respectively). The mean increase in platelet count in the five responders was 44 x 10(9)/lL (range: 28 to 90 x 10(9)/l). The average peak platelet count in the responders was 81 x 10(9)/l (range: 62 to 136 x 10(9)/l). Duration of response ranged from four to 18+ months, with the shortest responses observed in the two patients treated with a shorter course of INF. Response was independent of the presence of cirrhosis. Responding patients had improvement in hepatic transaminases, reduction in cryoglobulin and anticardiolipin antibodies, and HCV plasma RNA when tested. Relapse was associated with an increase in these laboratory markers of HCV infection. We conclude that INF can be an effective treatment in patients with HCV-related thrombocytopenia.

Origin of antiphospholipid antibodies

Our observations and those from others give further support to our hypothesis that "autoimmune aPL" may be generated by immunization with products from bacteria or viruses after incidental exposure or infection. We also were able to generate an APS-like syndrome in a strain of mice susceptible to autoimmunity, indicating that other factors such as genetic factors are likely to be involved in development of APS. Furthermore, not all aPL generated by immunization with bacterial or viral products were pathogenic. Based on the clinical experience and on the numerous reports indicating the presence of aPL in large number of infectious diseases, it may be expected that not all aPL produced during infection are pathogenic. We hypothesize that a limited number aPL induced by certain viral or bacterial products would be pathogenic in certain groups of predisposed individuals. Identification of those bacterial or viral agents may help to find strategies for the prevention of production of "pathogenic" aPL. Alternatively, free peptides may be used to induce tolerance against aPL production.

The antiphospholipid syndrome and infection

Infectious agents have been implicated in the induction of antiphospholipid (aPL) antibodies and the development of the antiphospholipid syndrome (APS). This review focuses on the types of aPL antibodies detected in infections and addresses whether these antibodies are of clinical importance in patients with infections. Hepatitis C virus (HCV) infection is given special attention because this virus has the propensity to induce various autoimmune phenomena. Several aspects are emphasized that should be considered carefully when interpreting results. Most of the published data agree that thrombophilia is not observed in patients with infections (including HCV) because aPL antibodies are mostly the natural or nonpathogenic type. Thus, we do not recommend routinely testing for HCV in patients with APS. However, not all infection-associated aPL antibodies are cofactor independent. For instance, infections are increasingly recognized as a major precipitating condition of the catastrophic variant of APS, perhaps via mechanisms of molecular mimicry. Therefore, it may be possible to prevent this devastating evolution if the infectious process is promptly recognized and exhaustively treated.

Cofactor dependence and isotype distribution of anticardiolipin antibodies in viral infections

BACKGROUND

Antibodies to cardiolipin (aCLs) are often detected in patients with autoimmune disorders or infectious diseases.

OBJECTIVE

To investigate the distribution of aCL isotypes and requirement of protein cofactor in viral infections in order to establish the importance, if any, of these antibodies in these infectious diseases.

PATIENTS AND METHODS

The isotype distribution of aCLs in the sera from 160 patients with infection caused by HIV-1 (n=40), hepatitis A virus (n=40), hepatitis B virus (n=40), or hepatitis C virus (n=40) was studied by standardised enzyme linked immunosorbent assay (ELISA) in the presence and absence of protein cofactor (mainly beta2-glycoprotein I). Serum samples from healthy volunteers and patients with syphilis and antiphospholipid syndrome were also included and served as negative and positive control groups respectively.

RESULTS

The prevalence of one or more aCL isotypes in serum of patients with HIV-1, hepatitis A virus, hepatitis B virus, or hepatitis C virus infection was 47%, 92%, 42%, and 17% respectively (principally IgM and/or IgA). Most of these antibodies were mainly cofactor independent.

CONCLUSIONS

The presence of aCLs in viral infections is principally cofactor independent, suggesting that cofactor dependence of the aCLs should be assessed to distinguish subjects most likely to suffer from clinical symptoms observed in the presence of these antibodies.

Testing for antiphospholipid antibodies: problems and solutions

The first aCL test was developed in 1983 and subsequently standardized. Although new and more specific tests have become available, the aCL ELISA and the LA tests are still the first choice to be used in diagnosis of APS. Newer tests such as the anti beta 2 GP1 ELISA and the APhL ELISA Kit (Louisville APL Diagnostics) use somewhat different antigens and likely provide a more specific (and possibly more reliable) diagnosis of APS while retaining good-to-excellent sensitivity. Other tests, such as ELISA for prothrombin antibodies and annexin V antibodies, are still undergoing development and will require standardization and extensive evaluation. We thank Dr Isabel Abreu and Dr Mittermeyer B. Santiago for performing some of the studies reported in this review.

Pulmonary embolism and transitory anti-beta2-GPI antibodies in an adult with chicken pox

Anti-beta2-glycoprotein I antibodies are considered as a specific marker for the antiphospholipid syndrome. In contrast to lupus circulating anticoagulant and anticardiolipin (aCL) antibodies, they are usually not found at significant levels in infections. We report a case of pulmonary embolism in an adult with varicella. Transient significant levels of aCL antibodies and of IgM anti-beta2-GPI antibodies were observed. No other prothrombotic factor, including free protein S antigen deficiency, was found. The direct pathogenic role of these transient antibodies on the thrombotic event may then be suspected. They are probably associated with VZV acute infection and are absent two months after varicella.

High prevalence of antiphospholipid antibodies in leprosy: evaluation of antigen reactivity

Antiphospholipid antibodies (aPL) have been reported not only in autoimmune disorders but also in various infectious diseases. Accumulating evidence indicates that beta2 glycoprotein I (beta2GPI) and prothrombin are the main proteins to which autoimmune aPL bind. The aim of this study was to evaluate the prevalence of different aPL in patients with leprosy. We included 51 outpatients (42 lepromatous and 9 borderline leprosy) without any clinical feature of the antiphospholipid syndrome (APS). 35 had lupus anticoagulant and 31 had anticardiolipin antibodies (aCL). Anti-beta2GPI antibodies were highly positive in 29/51 and anti- prothrombin antibodies (anti-II) were detected in 23/51. Almost all aCL and anti-beta2GPI were of IgM isotype, while IgG isotype was more frequent among anti-II. No statistical difference was found when aPL were evaluated in patients grouped according to their bacteriological status. Furthermore, patients under treatment (n=33) had a similar frequency of positive aPL compared to patients in vigilance (n=14). Assessing the specificity of antibody binding to CL and beta2GPI in ELISA by means of inhibition studies with cardiolipin-beta2GPI liposomes, leprosy and APS sera showed a similar behaviour. Comparable results were also found in both groups of patients when inhibition experiments with lysate of Mycobacterium leprae were carried out. In summary, leprosy-related aPL resemble those found in patients with APS but the immunoglobulin isotype is different, with IgM much more prevalent in leprosy patients.

Retinal vein thrombosis associated with chronic hepatitis C: a case series and review of the literature

The role of procoagulant autoantibodies in hepatitis C virus (HCV) infection is unclear. Three individuals with HCV infection and a unique genetic hypercoagulable state developed retinal vein thrombosis (RVT) in association with interferon-alpha (IFN-alpha) therapy. It is probable that a combination of active HCV infection in a genetically susceptible individual receiving IFN-alpha accounted for the observed RVT.

Which are the best biological markers of the antiphospholipid syndrome?

The diagnosis of antiphospholipid syndrome (APS) requires the presence of both clinical and biological features. Due to the heterogeneity of anti-phospholipid antibodies (aPL) the laboratory approach for their detection includes clotting-based tests for lupus anticoagulant (LA) as well as solid-phase assays for anticardiolipin antibodies (aCL). In addition, as it has been shown that autoimmune aPL recognize epitopes on phospholipid (PL)-binding plasma proteins, assays detecting antibodies to beta 2-glycoprotein I (beta 2-GPI) or prothrombin have been developed. The association between venous or arterial thrombosis and recurrent fetal loss with the presence of conventional aPL (LA and/or aCL) has been confirmed by many studies. The LA and IgG aCL at moderate/high titre seem to exhibit the strongest association with clinical manifestations of the APS. Several reports indicate that LA is less sensitive but more specific than aCL for the APS. Assays against PLs other than CL as well as the use of mixtures of PLs have been proposed to improve the detection of APS-related aPL. Concerning antibodies to PL-binding proteins (detected in the absence of PLs), there is evidence that anti-beta 2-GPI are closely associated with thrombosis and other clinical features of the APS. Moreover, these antibodies may be more specific in the recognition of the APS and in some cases may be present in the absence of aPL detected by standard tests. Many issues are still under debate and are discussed in this review, such as the problems of standardization of anti-beta 2-GPI assays, detection of the IgA isotype of aCL and anti-beta 2-GPI, the coagulation profiles of LA in the recognition of the thrombotic risk and the association of particular markers with subsets of patients with APS.