Acute cytomegalovirus infection and venous thrombosis: role of antiphospholipid antibodies

Venous thromboembolism in viral diseases: A comprehensive literature review

Venous thromboembolism (VTE) is known to be a common respiratory and/or cardiovascular complication in hospitalized patients with viral infections. Numerous studies have proven human immunodeficiency virus infection to be a prothrombotic condition. An elevated VTE risk has been observed in critically ill H1N1 influenza patients. VTE risk is remarkably higher in patients infected with the Hepatitis C virus in contrast to uninfected subjects. The elevation of D-dimer levels supported the association between Chikungunya and the Zika virus and the rise of clinical VTE risk. Varicella-zoster virus is a risk factor for both cellulitis and the consequent invasive bacterial disease which may take part in thrombotic initiation. Eventually, hospitalized patients infected with the coronavirus disease of 2019 (COVID-19), the cause of the ongoing worldwide pandemic, could mainly suffer from an anomalous risk of coagulation activation with enhanced venous thrombosis events and poor quality clinical course. Although the risk of VTE in nonhospitalized COVID-19 patients is not known yet, there are a large number of guidelines and studies on thromboprophylaxis administration for COVID-19 cases. This study aims to take a detailed look at the effect of viral diseases on VTE, the epidemiology of VTE in viral diseases, and the diagnosis and treatment of VTE.

Transient Anti-Phospholipid Antibodies in Two Patients With COVID-19

We report two cases of coronavirus disease 2019 (COVID-19) in patients who developed pulmonary embolism and transient anti-phospholipid antibodies. At the time of presentation with acute pulmonary embolism, both patients had leukocytosis and increased levels of anti-cardiolipin antibodies, which resolved at testing 12 weeks after initial presentation. Studying cases of pulmonary embolism and increased anti-phospholipid antibodies in the context of COVID-19 could be one of the factors for elucidating the possible connection between severe acute respiratory syndrome coronavirus 2 infection, anti-phospholipid antibodies, and thrombosis.

Overview of Covid-19 Regarding the Cardiovascular Situation in the Light of Current Reports

Nowadays Coronavirus Disease 2019 (Covid-19) is increasing mortality all over the world mercilessly. We are learning almost every day about its new symptoms and that it mutates quickly. This disease has tied us up and made us desperate. The death rate from this disease has increased in patients who had pre-existing medical conditions, especially cardiovascular ones, by eliminating the angiotensin-converting enzyme (ACE)-2 receptor in the lungs. Also, ACE1 and angiotensin receptor blockers (ARB) may stimulate ACE2 expression and worse the prognosis. Intravenous infusions of ACEIs and ARBs in experimental animals increase the number of ACE2 receptors. Therefore, it may be one of the reasons that COVID-19 infects the cells of patients treating hypertension. However, most of the congress of cardiology do not recommend to discontinue these anti-hypertensive drugs. Therefore, this brief report evaluates Covid-19 in the view of cardiovascular diseases taking into account current reports and suggests some possible solutions to keep the virus under control.

Cytomegalovirus-Associated Venous and Arterial Thrombotic Disease

BACKGROUND

Cytomegalovirus (CMV) infection has been associated with venous thromboembolism (VTE) and acute coronary syndromes (ACS).

METHODS

A retrospective study was conducted within the OSF HealthCare System in Peoria, IL. The objectives were to determine the incidence of acute VTE and ACS within one year of CMV testing. The "study group" included patients with positive CMV immunoglobulin M (IgM) or positive CMV polymerase chain reaction (PCR). The "seropositive control" group included patients with positive CMV immunoglobulin G (IgG) and negative IgM. The "seronegative control" group included patients with negative CMV IgG and IgM, or negative PCR.

RESULTS

Within one year of CMV infection, 38 of 379 patients (10.0%) developed VTE in the study group compared to 41 of 1334 patients (3.1%) in the seropositive control and 37 of 1249 (3.0%) in the seronegative control. Adjusting for age and gender, both control groups were less likely to have VTE than the study group within one year (seropositive control: odds ratio (OR) = 0.3, 95% confidence interval (CI) 0.2-0.5, p < 0.0001; seronegative control: OR = 0.4, 95% CI 0.2-0.6, p < 0.0001). ACS was more likely to occur in the study group, with the incidence of 7.7% compared to 4.7% (p < 0.0001) in the seropositive control and 1.9% (p <0.0001) in the seronegative control. Adjusting for age and gender, the seronegative control was less likely to develop ACS than the study group within one year (OR = 0.4, 95% CI 0.2-0.7, p = 0.003).

CONCLUSIONS

This retrospective study demonstrates that CMV infection may be a significant risk factor for VTE and ACS.

Pulmonary Artery Thrombosis: A Diagnosis That Strives for Its Independence

According to a widespread theory, thrombotic masses are not formed in the pulmonary artery (PA) but result from migration of blood clots from the venous system. This concept has prevailed in clinical practice for more than a century. However, a new technologic era has brought forth more diagnostic possibilities, and it has been shown that thrombotic masses in the PA could, in many cases, be found without any obvious source of emboli. Chronic obstructive pulmonary disease, asthma, sickle cell anemia, emergency and elective surgery, viral pneumonia, and other conditions could be complicated by PA thrombosis development without concomitant deep vein thrombosis (DVT). Different pathologies have different causes for local PA thrombotic process. As evidenced by experimental results and clinical observations, endothelial and platelet activation are the crucial mechanisms of this process. Endothelial dysfunction can impair antithrombotic function of the arterial wall through downregulation of endothelial nitric oxide synthase (eNOS) or via stimulation of adhesion receptor expression. Hypoxia, proinflammatory cytokines, or genetic mutations may underlie the procoagulant phenotype of the PA endothelium. Both endotheliocytes and platelets could be activated by protease mediated receptor (PAR)- and receptors for advanced glycation end (RAGE)-dependent mechanisms. Hypoxia, in particular induced by high altitudes, could play a role in thrombotic complications as a trigger of platelet activity. In this review, we discuss potential mechanisms of PA thrombosis in situ.

Stroke as a complication and prognostic factor of COVID-19

Introduction

Methods

Conclusions

Stroke as a complication and prognostic factor of COVID-19

INTRODUCTION

Contradictory data have been reported on the incidence of stroke in patients with COVID-19 and the risk of SARS-CoV-2 infection among patients with history of stroke.

METHODS

This study systematically reviews case series reporting stroke as a complication of COVID-19, and analyses the prognosis of patients with COVID-19 and history of stroke. The pathophysiological mechanisms of stroke in patients with COVID-19 are also reviewed.

CONCLUSIONS

History of stroke increases the risk of death due to COVID-19 by 3 times. Stroke currently seems not to be one of the main complications of COVID-19.

Environmental Triggers of Autoreactive Responses: Induction of Antiphospholipid Antibody Formation

Antiphospholipid antibodies (aPLs) comprise a diverse family of autoantibodies targeted against proteins with the affinity toward negatively charged phospholipids or protein-phospholipid complexes. Their clinical significance, including prothrombotic potential of anti-cardiolipin antibodies (aCLs), anti-β2-glycoprotein I antibodies (aβ2-GPIs), and lupus anti-coagulant (LA), is well-established. However, the ontogeny of these pathogenic aPLs remains less clear. While transient appearance of aPLs could be induced by various environmental factors, in genetically predisposed individuals these factors may eventually lead to the development of the antiphospholipid syndrome (APS). Since the first description of APS, it has been found that a wide variety of microbial and viral agents influence aPLs production and contribute to clinical manifestations of APS. Many theories attempted to explain the pathogenic potential of different environmental factors as well as a phenomenon termed molecular mimicry between β2-GPI molecule and infection-relevant structures. In this review, we summarize and critically assess the pathogenic and non-pathogenic formation of aPLs and its contribution to the development of APS.

Antiphospholipid antibody syndrome with thrombotic splenic infarcts associated with acute cytomegalovirus infection

INTRODUCTION

We describe a case of acute cytomegalovirus (CMV) infection complicated by acquired antiphospholipid antibodies and splenic thrombi. We discuss the associations between CMV infection and thrombosis risk and correlation with antiphospolipid antibodies.

CASE PRESENTATION

A previously healthy 32-year-old woman is hospitalized for acute abdominal pain and fever and found to have multiple splenic infarcts on an abdominal computed tomography (CT) scan. An infectious work-up is negative except for acute CMV, and a hypercoagulable work-up is only positive for antiphospholipid antibodies. The patient is discharged and placed on anti-coagulation therapy for 6 months.

CONCLUSION

Co-incident thrombosis and antiphospholipid antibody syndrome can occur with acute viral infections, including CMV. We discuss the viral infection-associated increased risk of developing blood clots and antiphospholipid antibodies as being either correlative with or causative of viral-induced thrombosis.

Splenic Infarct and Pulmonary Embolism as a Rare Manifestation of Cytomegalovirus Infection

Cytomegalovirus (CMV) is a type of herpes infection that has a characteristic feature of maintaining lifelong latency within the host cell. CMV manifestations can cover a broad spectrum from fever to as severe as pancytopenia, hepatitis, retinitis, meningoencephalitis, Guillain-Barre syndrome, pneumonia, and thrombosis. Multiple case reports of thrombosis associated with CMV have been reported. Deep vein thrombosis or pulmonary embolism is more common in immunocompetent patients while splenic infarct is more common in immunocompromised patients. However, here we report a female patient on low-dose methotrexate for rheumatoid arthritis who presented with both pulmonary embolism and splenic infarct.

Pulmonary Embolism in a Young Immunocompetent Adult Infected with Cytomegalovirus. Are Novel Oral Anticoagulants an Efficient Alternative?

BACKGROUND/AIM

Cytomegalovirus (CMV) infection is a common disease especially in young adults. Thromboembolism like deep vein thrombosis and pulmonary embolism is increased among patients with CMV infection. Most cases represent immunocompromised patients usually treated with low molecular weight heparin.

CASE REPORT

Herein, we describe a 25-year-old immunocompetent male who presented at the emergency department with sudden onset of chest pain. One month prior to admission, he had developed persistent fever and cough and the diagnosis of CMV infection had been established. After extensive workup, the diagnosis of pulmonary embolism after CMV infection was set and he was treated with rivaroxaban. During the next six months the patient continued on the same anticoagulant therapy with no other episode of pulmonary embolism at 1-year follow-up.

CONCLUSION

To our knowledge, this is the first case of CMV-associated pulmonary embolism treated with novel oral anticoagulants (NOACs). NOACs, such as rivaroxaban, seem to be safe and may represent an attractive alternative with promising results in this particular group of patients. Studies incorporating a greater cohort of patients are needed in order to draw safe conclusions regarding the relationship between NOACs and CMV infection.

Thrombosis and antiphospholipid antibody syndrome during acute Q fever: A cross-sectional study

Q fever is a neglected and potentially fatal disease. During acute Q fever, antiphospholipid antibodies are very prevalent and have been associated with fever, thrombocytopenia, acquired heart valve disease, and progression to chronic endocarditis. However, thrombosis, the main clinical criterion of the 2006 updated classification of the antiphospholipid syndrome, has not been assessed in this context. To test whether thrombosis is associated with antiphospholipid antibodies and whether the criteria for antiphospholipid syndrome can be met in patients with acute Q fever, we conducted a cross-sectional study at the French National Referral Center for Q fever.Patients included were diagnosed with acute Q fever in our Center between January 2007 and December 2015. Each patient's history and clinical characteristics were recorded with a standardized questionnaire. Predictive factors associated with thrombosis were assessed using a rare events logistic regression model. IgG anticardiolipin antibodies (IgG aCL) assessed by an enzyme-linked immunosorbent assay were tested on the Q fever diagnostic serum. A dose-dependent relationship between IgG aCL levels and thrombosis was tested using a receiver operating characteristic (ROC) analysis.Of the 664 patients identified for inclusion in the study, 313 (47.1%) had positive IgG aCL and 13 (1.9%) were diagnosed with thrombosis. Three patients fulfilled the antiphospholipid syndrome criteria. After multiple adjustments, only positive IgG aCL (relative risk, 14.46 [1.85-113.14], P = .011) were independently associated with thrombosis. ROC analysis identified a dose-dependent relationship between IgG aCL levels and occurrence of thrombosis (area under curve, 0.83, 95%CI [0.73-0.93], P < .001).During acute Q fever, antiphospholipid antibodies are associated with thrombosis, thrombocytopenia, and acquired valvular heart disease. Antiphospholipid antibodies should be systematically assessed in acute Q fever patients. Hydroxychloroquine, which has been previously shown to antagonize IgG aCL pathogenic properties, should be tested in acute Q fever patients with anticardiolipin antibodies to prevent antiphospholipid-associated complications.Key Point: In addition to fever, thrombocytopenia and acquired valvular heart disease, antiphospholipid antibodies are associated with thrombosis during acute Q fever.

Acute Cytomegalovirus Infection as a Rare Cause of Portal Vein Thrombosis with Small Bowel Infarction in an Immunocompetent Patient

Portal vein thrombosis (PVT) refers to thrombosis that develops in the trunk of the portal vein including its right and left intrahepatic branches and may even extend to the splenic or superior mesenteric veins. PVT due to Cytomegalovirus (CMV) infection is a rare complication, scarcely described in English literature. We present a case of a 58-year-old immunocompetent patient with PVT and small bowel ischemia.

Systematic review of case reports of antiphospholipid syndrome following infection

OBJECTIVE

The objective of this study was to conduct a systematic review of case reports documenting the development of antiphospholipid syndrome or antiphospholipid syndrome-related features after an infection.

METHODS

We searched Medline, EMBASE, Web of Science, PubMed ePubs, and The Cochrane Library - CENTRAL through March 2015 without restrictions. Studies reporting cases of antiphospholipid syndrome or antiphospholipid syndrome-related features following an infection were included.

RESULTS

Two hundred and fifty-nine publications met inclusion criteria, reporting on 293 cases. Three different groups of patients were identified; group 1 included patients who fulfilled the criteria for definitive antiphospholipid syndrome (24.6%), group 2 included patients who developed transient antiphospholipid antibodies with thromboembolic phenomena (43.7%), and group 3 included patients who developed transient antiphospholipid antibodies without thromboembolic events (31.7%). The most common preceding infection was viral (55.6%). In cases that developed thromboembolic events Human immunodeficiency and Hepatitis C viruses were the most frequently reported. Parvovirus B19 was the most common in cases that developed antibodies without thromboembolic events. Hematological manifestations and peripheral thrombosis were the most common clinical manifestations. Positive anticardiolipin antibodies were the most frequent antibodies reported, primarily coexisting IgG and IgM isotypes. Few patients in groups 1 and 2 had persistent antiphospholipid antibodies for more than 6 months. Outcome was variable with some cases reporting persistent antiphospholipid syndrome features and others achieving complete resolution of clinical events.

CONCLUSIONS

Development of antiphospholipid antibodies with all traditional manifestations of antiphospholipid syndrome were observed after variety of infections, most frequently after chronic viral infections with Human immunodeficiency and Hepatitis C. The causal relationship between infection and antiphospholipid syndrome cannot be established, but the possible contribution of various infections in the pathogenesis of antiphospholipid syndrome need further longitudinal and controlled studies to establish the incidence, and better quantify the risk and the outcomes of antiphospholipid-related events after infection.

Venous thromboembolism associated with acute cytomegalovirus infection: epidemiology and predisposing conditions

BACKGROUND

Venous thromboembolism has been reported in association with cytomegalovirus (CMV) infection both in immunocompromised and immunocompetent patients. In this population, it is yet undetermined whether CMV alone provokes VTE or other predisposing conditions are involved.

MATERIALS AND METHODS

1007 VTE patients consecutively recruited in one academic hospital were analyzed retrospectively in order to identify acute CMV infection. Acquired and inherited risk factors were screened. Only adults and immunocompetent patients were included.

RESULTS

Among 1007 consecutive VTE patients, we identified 10 patients with synchronous acute CMV infection. Patients with coexistent VTE and acute CMV infection were younger (37.5 years vs. 56.6 years; p = 0.0088) and exhibited a female predominance (90% vs. 56%; p = 0.026), in comparison to the whole cohort. Hereditary thrombophilia was identified in 9 out of 10 patients. Acquired risk factors for VTE like estrogens administration and pregnancy were equally prevalent in patients with and without CMV infection.

CONCLUSION

Acute CMV infection is a potential contributor to VTE whenever other prothrombotic conditions are required. This should help clinicians to privilege a limited duration of anticoagulant treatment like in other provoked VTE.

Pulmonary embolism in an immunocompetent patient with acute cytomegalovirus colitis

Acute cytomegalovirus (CMV) infection occurs commonly in immunocompromised and immunocompetent patients, but is usually asymptomatic in the latter. Vascular events associated with acute CMV infection have been described, but are rare. Hence, such events are rarely reported in the literature. We report a case of pulmonary embolism secondary to acute CMV colitis in an immunocompetent 78-year-old man. The patient presented with fever and diarrhea. Colonic ulcers were diagnosed based on colonoscopy findings, and CMV was the proven etiology on pathological examination. The patient subsequently experienced acute respiratory failure. Pulmonary embolism was diagnosed based on the chest radiography and computed tomography findings. A diagnosis of acute CMV colitis complicated by pulmonary embolism was made. The patient was successfully treated with intravenous administration of unfractionated heparin and intravenous ganciclovir.

Cytomegalovirus-associated portal vein thrombosis in an immunocompetent patient: an underestimated complication

We describe an immunocompetent adult with acute cytomegalovirus (CMV) infection complicated by extensive portal vein thrombosis. A literature review on the incidence, presentation, pathophysiology and management of CMV-associated thrombosis is included. Previously thought to be a rare complication, recent large case series and the present case reconfirm the increasing prevalence of CMV-associated thromboembolism in the immunocompetent adult.

Thrombosis associated with acute cytomegalovirus infection: a narrative review

Thrombosis associated with acute cytomegalovirus infection has been reported many times in the literature since the mid 1980s - mainly in case reports and in small case series, but also in four controlled studies. Still, many physicians are unaware of this association although acute cytomegalovirus infection diagnosis in a thrombosis patient may warrant antiviral therapy and may affect anticoagulation therapy duration. Accordingly, the clinical characteristics of patients with thrombosis and acute cytomegalovirus infection are reviewed, and the current knowledge concerning this unique association is presented herein. We believe it is time to add acute cytomegalovirus infection to the list of thrombosis triggers.

Transient antiphospholipid syndrome associated with primary cytomegalovirus infection: a case report and literature review

Viral infection is known to induce transient autoimmunity in humans. Acute cytomegalovirus (CMV) infection is implicated in occasional thrombosis formation. We here, for the first time, report a 19-year-old female who had an acute CMV infection, leading to a deep venous thrombosis and a pulmonary embolism along with transient appearance of lupus anticoagulant. The pathological role of antiphospholipid antibodies in CMV-mediated thrombosis is discussed.

Thrombosis Associated with Viral Hepatitis

Viral hepatitis may promote the development of venous thromboembolism (VTE) and, more specifically, portal vein thrombosis (PVT). In this narrative review, we summarize the clinical data and discuss the possible pathogenetic roles of cytomegalovirus (CMV), Epstein-Barr virus (EBV), and hepatitis A, B, and C viruses (HAV, HBV, HCV) in the occurrence of VTE. CMV is the first qualified candidate to enter the list of VTE minor risk factors, and in the rare case of fulminant infection, both EBV and CMV, like any severe infection or inflammatory disease, increase risk for thrombosis. In chronic hepatitis B and C, it remains controversial whether antiphospholipid antibodies are important for thrombotic complications or merely an epiphenomenon. Retinal vein occlusion described in chronic hepatitis C is usually attributed to the treatment with interferon. Eltrombopag, used for HCV-related thrombocytopenia, has been associated with increased thrombotic risk. The imbalance between procoagulant and anticoagulant factors associated with chronic liver disease may have clinical implications. This may help to explain why these patients are not protected from clinical events such as VTE, PVT, and the progression of liver fibrosis.

Platelets, acting in part via P-selectin, mediate cytomegalovirus-induced microvascular dysfunction

Cytomegalovirus (CMV) infects a majority of the population worldwide. It has been implicated in cardiovascular disease, induces microvascular dysfunction, and synergizes with hypercholesterolemia to promote leukocyte and platelet recruitment in venules. Although platelets and platelet-associated P-selectin contribute to cardiovascular disease inflammation, their role in CMV-induced vascular responses is unknown. We assessed the role of platelets in CMV-induced microvascular dysfunction by depleting platelets and developing bone marrow chimeric mice deficient in platelet P-selectin. Wild-type and chimeric mice received mock or murine (m)CMV intraperitoneally. Five weeks later, some mice were switched to a high-cholesterol diet (HC) to investigate the synergism between mCMV and HC. Arteriolar vasodilation and recruitment of leukocytes and donor platelets in venules were measured at 11wk. mCMV with or without HC caused significant endothelial dysfunction in arterioles. Platelet depletion restored normal vasodilation in mCMV-HC but not mCMV-ND mice, whereas protection was seen in both groups for platelet P-selectin chimeras. Only mCMV + HC elevated leukocyte and platelet recruitment in venules. Leukocyte adhesion was reduced to mock levels by acute platelet depletion but was only partially decreased in platelet P-selectin chimeras. Platelets from mCMV-HC mice and, to a lesser extent, mCMV-ND but not mock-HC mice showed significant adhesion in mCMV-HC recipients. Our findings implicate a role for platelets, acting through P-selectin, in CMV-induced arteriolar dysfunction and suggest that the addition of HC leads to a platelet-dependent, inflammatory infiltrate that is only partly platelet P-selectin dependent. CMV appeared to have a stronger activating influence than HC on platelets and may represent an additional therapeutic target in vulnerable patients.

Myopericarditis complicated by pulmonary embolism in an immunocompetent patient with acute cytomegalovirus infection: a case report

Background

Primary acute cytomegalovirus infection in immunocompetent patients is common worldwide. Infection is most often asymptomatic or occurs sub-clinically with a self-limited mononucleosis-like syndrome. More rarely, the infection may lead to severe organ complications with pneumonia, myocarditis, pericarditis, colitis and hemolytic anemia. Recent cases of cytomegalovirus-associated thrombosis have also been reported sporadically in the medical literature.

Case presentation

We report here a case of simultaneous myopericarditis and pulmonary embolism in a 30-year-old man with no medical history. The patient was not immunocompromised. We discuss the possible role of acute cytomegalovirus infection in the induction of vascular damage and review relevant cases in the literature.

Conclusion

Thrombosis in patients with acute cytomegalovirus infection may be more frequent than is generally thought. Physicians need to be aware of the possible association between acute cytomegalovirus and thrombosis in immunocompetent patients, especially in the presence of severe systemic infection, as our case illustrates.

Acute cytomegalovirus infection in liver transplant recipients: An independent risk for venous thromboembolism

Acute cytomegalovirus (CMV) infection is a commonly encountered complication in the post liver transplant setting. We present a case of a 71-year-old male with acute CMV infection, initially presenting with a gastrointestinal bleed due to acute CMV gastritis and later on complicated by acute venous thromboembolism occurring as an unprovoked event in the post liver transplant period. Traditional risk factors for venous thromboembolism have been well described in the medical literature. Sporadic cases of thromboembolism due to CMV infection in the immune compromised patients have been described, especially in the post kidney transplant patients. Liver transplant recipients are equally prone to CMV infection particularly in the first year after successful transplantation. Venous thromboembolism in this special population is particularly challenging due to the fact that these patients may have persistent thrombocytopenia and anticoagulation may be a challenge for the treating physician. Since liver transplantation is severely and universally limited by the availability of donor organs, we feel that this case report will provide valuable knowledge in the day to day management of these patients, whose clinical needs are complex and require a multidisciplinary approach in their care and management. Evidence and pathophysiology linking both the conditions is presented along with a brief discussion on the management, common scenarios encountered and potential impact in this special group of patients.

Laboratory diagnosis of antiphospholipid syndrome

Antiphospholipid syndrome is an intriguing clinical entity encountered by all physicians because of the wide range of clinical manifestations involving every organ system. Ordering a single test under the name "antiphospholipid antibody" does not rule out this entity. There are overlapping but distinct autoantibodies, and a positive result in one assay is conclusive despite a negative result in another. Laboratories continue to conduct several nonstandard tests as part of integrated kits and physicians should be familiar with them for proper interpretation of the results. Lupus anticoagulant testing is an integral part of every thrombophilia workup and should be performed regardless of the screening activated partial thromboplastin time or mixing study.

Thrombosis following acute cytomegalovirus infection: a community prospective study

Infection might be associated with increased risk of venous thromboembolism (VTE) and arterial thrombosis. Specific hypotheses have been raised regarding the procoagulant response induced by acute cytomegalovirus (CMV) infection. Accordingly, we investigated the 6-month incidence of VTE and/or arterial thrombosis in patients that had been tested positive for CMV-IgM antibodies in a large health maintenance organization. Logistic regression analysis was used to identify independent risk factors for VTE and arterial thrombosis. Among 90,515 patients eligible for the VTE analysis and 90,805 patients eligible for the arterial thrombosis analysis, 6,205 (6.9%) and 6,222 (6.9%) patients were tested positive for CMV-IgM antibodies, respectively. During 6 months of follow-up from index date, the incidence rates per 1,000 capita of VTE among CMV-IgM seropositive and CMV-IgM seronegative patients were 3.06 (19 patients) and 1.36 (115 patients), respectively (odds ratio (OR) 2.25; 95% confidence intervals (95% CI) 1.38-3.66; p = 0.003). CMV-IgM seropositivity was independently associated with VTE appearance (OR 2.49; 95% CI 1.53-4.06; p < 0.0001) following adjustment for age, sex, and other confounders. The incidence rates per 1,000 capita of arterial thrombosis among CMV-IgM seropositive and CMV-IgM seronegative patients were 1.12 (7 patients) and 1.06 (90 patients), respectively (OR 1.06; 95% CI 0.49-2.28; p = 0.840). CMV-IgM seropositivity was not associated with arterial thrombosis. We conclude that acute CMV infection might be associated with an increased short-term VTE risk. To the best of our knowledge, this is the largest study ever to confirm this association.

Review: Viral infections and mechanisms of thrombosis and bleeding

Viral infections are associated with coagulation disorders. All aspects of the coagulation cascade, primary hemostasis, coagulation, and fibrinolysis, can be affected. As a consequence, thrombosis and disseminated intravascular coagulation, hemorrhage, or both, may occur. Investigation of coagulation disorders as a consequence of different viral infections have not been performed uniformly. Common pathways are therefore not fully elucidated. In many severe viral infections there is no treatment other than supportive measures. A better understanding of the pathophysiology behind the association of viral infections and coagulation disorders is crucial for developing therapeutic strategies. This is of special importance in case of severe complications, such as those seen in hemorrhagic viral infections, the incidence of which is increasing worldwide. To date, only a few promising targets have been discovered, meaning the implementation in a clinical context is still hampered. This review discusses non‐hemorrhagic and hemorrhagic viruses for which sufficient data on the association with hemostasis and related clinical features is available. This will enable clinicians to interpret research data and place them into a perspective. J. Med. Virol. 84:1680–1696, 2012. © 2012 Wiley Periodicals, Inc.

Cytomegalovirus-induced cutaneous microangiopathy manifesting as lower limb ischemia in a human immunodeficiency virus-infected patient

Cutaneous infections by cytomegalovirus (CMV) are rare and often difficult to diagnose both clinically and histopathologically. A wide range of different clinical manifestations have been described in the literature, especially in immunosuppressed patients. CMV-induced thrombosis has also been reported in these patients, and various mechanisms have been proposed to explain the role of CMV in the thrombotic process, including direct damage of the endothelial cells, activation of coagulation factors and inducing the production of antiphospholipid antibodies. We present the case of a human immunodeficiency virus (HIV)-infected woman who developed distal ischemic lesions of the lower extremities during a generalized CMV infection. We discuss the role of CMV and antiphospholipid antibodies in the pathogenesis of thrombosis in immunosuppressed patients.

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.

Recent developments in our understanding of the antiphospholipid syndrome

The antiphospholipid syndrome is an autoimmune disease that manifests clinically as recurrent thrombotic complications or foetal losses and serologically with elevated levels of antiphospholipid antibodies in the plasmas of these patients. The term 'antiphospholipid syndrome' is confusing, because the auto-antibodies are not directed against phospholipids but towards a plasma protein, β(2) -glycoprotein I. For many years, the reason why auto-antibodies against β(2) -glycoprotein I were pro-thrombotic was unclear, because β(2) -glycoprotein I seems to be an obsolete protein in our circulation. Human and mice deficient in this protein do not express a clear phenotype. Recent studies on the structure and function of β(2) -glycoprotein I have provided novel insights into the importance of this protein in physiology and its role in the pathology of the antiphospholipid syndrome.

Induction of anti-β2 -glycoprotein I autoantibodies in mice by protein H of Streptococcus pyogenes

BACKGROUND

The antiphospholipid syndrome (APS) is characterized by the persistent presence of anti-β(2) -glycoprotein I (β(2) -GPI) autoantibodies. β(2) -GPI can exist in two conformations. In plasma it is a circular protein, whereas it adopts a fish-hook conformation after binding to phospholipids. Only the latter conformation is recognized by patient antibodies. β(2) -GPI has been shown to interact with Streptococcus pyogenes.

OBJECTIVE

To evaluate the potential of S. pyogenes-derived proteins to induce anti-β(2) -GPI autoantibodies.

METHODS AND RESULTS

Four S. pyogenes surface proteins (M1 protein, protein H, streptococcal collagen-like protein A [SclA], and streptococcal collagen-like protein B [SclB]) were found to interact with β(2) -GPI. Only binding to protein H induces a conformational change in β(2) -GPI, thereby exposing a cryptic epitope for APS-related autoantibodies. Mice were injected with the four proteins. Only mice injected with protein H developed antibodies against the patient antibody-related epitope in domain I of β(2) -GPI. Patients with pharyngotonsillitis caused by S. pyogenes who developed anti-protein H antibodies also generated anti-β(2) -GPI antibodies.

CONCLUSIONS

Our study has demonstrated that a bacterial protein can induce a conformational change in β(2) -GPI, resulting in the formation of antiβ(2) -GPI autoantibodies. This constitutes a novel mechanism for the formation of anti-β(2) -GPI autoantibodies.

Cytomegalovirus infection is associated with venous thromboembolism of immunocompetent adults--a case-control study

Cytomegalovirus (CMV) seems to contribute to the development of venous thromboembolism (VTE) in immunocompromised patients whereas literature data on the role in immunocompetent individuals are mainly limited to case reports. This study aimed to investigate if cytomegalovirus infection contributes to the development of VTE in immunocompetent individuals. CMV-IgG and CMV-IgM antibody titres, CMV-IgG avidity and CMV-DNA were identified in samples from 166 VTE patients and from 166 healthy blood donors matched for gender and age. CMV-IgG antibodies were found more frequently in VTE patients compared to controls [57.8% vs. 44.0%; adjusted OR 1.75 (95% CI 1.13-2.70); p = 0.016]. Accordingly, median CMV-IgG titres were significantly higher in the case group (89.4 vs. 1.8 AU/ml; p = 0.002). Although the overall rate was low, CMV-IgM antibodies were detected more often among cases than controls. The difference was significant in patients with an unprovoked VTE event [7.4% vs. 0.6%; adjusted OR 5.26 (95% CI 1.35-20.8); p = 0.017]. CMV-IgG antibodies of almost all VTE patients (98.9%) and controls (98.6%) were found to be of high avidity. The rate of positive CMV-DNA samples was low and not different between cases and controls. With the exception of age, no association was found between CMV seropositivity and established VTE risk factors within the VTE group. CMV infection seems to play a role in the development of VTE in immunocompetent patients. Recurrent infection might be more important than acute CMV infection.

Thrombosis associated with acute cytomegalovirus infection: a meta-analysis

BACKGROUND

Thrombosis associated with acute cytomegalovirus (CMV) infection has been reported in the medical literature almost 100 times thus far. Still, the clinical characteristics of patients with both conditions have never been systematically reviewed and described.

METHODS

A literature search was conducted for all (n=97) reports concerning thrombosis associated with acute CMV infection. The current knowledge concerning this unique association and previous clinical experience are presented here.

RESULTS

The incidence of thrombosis among acute CMV infection hospitalized patients was 6.4%, and the incidence of acute CMV infection among thrombosis hospitalized patients was 1.9-9.1%. Most (n=64; 65.9%) reported patients were immunocompetent. Mean age of reported patients was 39.7 ± 14.9 years. Female-male ratio was 1:1. DVT/PE, splanchnic vein thrombosis and splenic infarction were the most prevalent thromboses associated with acute CMV infection. While DVT/PE was more prevalent among immunocompromised patients, splanchnic vein thrombosis was more prevalent among immunocompetent patients. Inherited predispositions for thrombosis were significantly more prevalent among immunocompetent patients. Immunocompromised patients were treated with antiviral agents significantly more often. Duration of anticoagulation therapy varied significantly between reported patients. In-hospital mortality rates were 4.9-22.2%.

CONCLUSIONS

We believe physicians should be alert for symptoms and signs of thrombosis in patients with acute CMV infection, and for symptoms and signs of acute CMV infection in patients with thrombosis.

Inherited and acquired predispositions for thrombosis in immunocompetent patients with cytomegalovirus-associated thrombosis

BACKGROUND

Thrombosis is a rare complication of cytomegalovirus (CMV) infection in immunocompetent patients. The clinical circumstances of this complication have never been studied, to the best of our knowledge.

AIM

We reviewed all reports on CMV-associated thrombosis in immunocompetent adults found in the literature, in search for thrombosis risk factors other than CMV.

METHODS

Our search yielded 32 case reports and case series on CMV-associated thrombosis in immunocompetent adults. Reports on immunocompromised patients, infants and elderly patients were excluded. All reports were reviewed for other, acquired as well as inherited, predispositions for thrombosis.

RESULTS

Reports on 39 immunocompetent adults were reviewed, mean age for which was 34.9+/-10.8years. Overall, 14 (35.9%) patients had one or more acquired predispositions for thrombosis; 16 (45.7%) of the 35 patients that were investigated for inherited thrombophilias had one or more inherited predispositions for thrombosis. Only 12 (34.3%) patients were found to have no acquired or inherited predispositions for thrombosis other than CMV. The most common (n=13; 33.3%) acquired predisposition for thrombosis was daily use of oral contraceptives. The most common (n=6; 17.1%) inherited predisposition for thrombosis was factor V Leiden mutation.

CONCLUSIONS

Most immunocompetent adults with CMV-associated thrombosis have other acquired or inherited predispositions for thrombosis. Hence, addressing these predispositions in patients with CMV-associated thrombosis may be of great clinical importance.

Cytomegalovirus-associated superior mesenteric vein thrombosis treated with systemic and in-situ thrombolysis

A 56-year-old patient, first diagnosed with an acute cytomegalovirus infection, presented with progressive abdominal pain because of a superior mesenteric vein thrombosis for which he was treated with systemic thrombolysis and heparin in continuous infusion. As this therapy did not have the intended success after 5 days, an interventional radiological procedure was performed with local thrombolysis in the superior mesenteric artery resulting in recanalisation of the vein. Oral anticoagulation was initiated and continued for a period of 6 months. Mesenteric venous thrombosis is a relatively uncommon cause of mesenteric ischemia that can be associated with severe morbidity and significant mortality. With noninvasive techniques, it is possible to establish a diagnosis in the majority of the cases. The importance of an early diagnosis and therapy - not only with anticoagulation, but also thrombolysis in selected cases - is shown with this case and review of the literature.

Pulmonary thrombosis with transient antiphospholipid syndrome after mononucleosis-like illness

Antiphospholipid antibodies (aPL) have been reported to occur in numerous viral infections. We report a 24-year-old Japanese woman, who developed multiple venous thrombosis associated with the elevation of anticardiolipin IgM after acute viral infection presenting a mononucleosis-like illness. Two months later, aPL and thromboses disappeared. In this case both parvovirus B19 and cytomegalovirus antibodies IgM were elevated, which indicated the possibility of cross-reaction.

Pulmonary embolism and portal vein thrombosis in an immunocompetent adolescent with acute cytomegalovirus hepatitis

Cytomegalovirus infection is usually asymptomatic or resembles infectious mononucleosis with fever, pharyngitis, arthralgias, lymphadenopathy, and atypical lymphocytosis. Even though primary CMV infection is usually self-limited in healthy individuals, significant complications can develop in immunocompromised patients. Venous or arterial thromboembolic phenomena are uncommon, yet very serious complications of CMV infection. Most published reports describe immunosupressed patients after organ transplantation or in the presence of HIV co-infection. However, thrombotic events in CMV infected immunocompetent individuals may occur. We describe the case of an immunocompetent adolescent with acute cytomegalovirus hepatitis that was complicated with pulmonary embolism and portal vein thrombosis. To our knowledge, this is the first reported case in which these two thrombotic phenomena occurred simultaneously in an adolescent with no obvious predisposing factors for thrombosis in the setting of an acute CMV infection.

Review: thromboses among HIV-infected patients during the highly active antiretroviral therapy era

Venous thrombotic events (VTEs) may occur at higher rates among patients with HIV; some studies suggest that highly active antiretroviral therapy (HAART) may increase the risk for these potentially life-threatening events. We performed a retrospective study among patients with HIV to evaluate the incidence and risk factors for VTEs during the HAART era. A literature review was performed examining VTEs in the pre- and post-HAART eras. Seventeen (3.7%) of 465 patients with HIV experienced a VTE. The overall incidence rate of deep VTEs among HIV-positive persons was 377 cases per 100,000 person-years, a fourfold higher rate compared to age-matched males in the general population. The median age at VTE was 36 years (range, 27-68). Patients with a thrombosis compared to those without had significantly lower current CD4 (153 versus 520 cells/mm(3), p < 0.001) and nadir (76 versus 276 cells/mm(3), p < 0.001) CD4 counts, higher viral loads (3.6 versus 1.7 log(10) copies per milliliter, p = 0.003), and more likely to have a diagnosis of AIDS (76% versus 32%, p < 0.001); there were no differences in demographics, hyperlipidemia, current use of HAART, the duration of HAART or protease inhibitor (PI) exposure. A review of the literature noted 129 VTE cases; mean age was 40 years, mean CD4 count was 181 cells/mm(3), the majority of patients were not receiving HAART, and the most common risk factor was an ongoing infection. Thrombotic events are occurring among patients with HIV despite their relatively young ages. Advanced HIV disease is a risk factor for development of thromboses, possibly due to an increased inflammatory state or the presence of concurrent comorbidities such as infections. HAART or PI therapy does not appear to play a significant role in the occurrence of VTEs.

Venous thromboembolism in patients with HIV/AIDS: a case-control study

BACKGROUND

Retrospective cohort studies of HIV-infected patients suggest an incidence of venous thromboembolism (VTE) of 1% to 2%, which is 10 times that expected among people without HIV. We investigated the prevalence of established risk factors for VTE in this population and explored novel risk factors.

METHODS

We conducted a case-control study using patients in the Johns Hopkins University AIDS Service cohort. We used conditional logistic regression and paired t tests to test for covariates significantly associated with VTE.

RESULTS

We identified 160 patients with VTE diagnosed radiologically or with a clinical course consistent with VTE; 23% of the cases of VTE were diagnosed in hospitalized patients. The incidence of VTE was approximately 0.5% per patient-year. Patients with VTE and control patients did not differ by gender, but black patients were overrepresented among those with VTE (odds ratio [OR]=1.9, 95% confidence interval [CI]: 1.11 to 3.08) and patients with VTE were older than controls (mean: 39 vs. 37 years; P=0.001). Patients with VTE had lower CD4 counts (229 vs. 362 cells/mm; P<0.0001), higher HIV RNA titers (120,254 vs. 71,262 copies/mL; P=0.013), and lower hemoglobin concentrations (11.4 vs. 12.7 g/dL; P<0.0001) preceding the event than those without VTE. The use of highly active antiretroviral therapy was not associated with VTE. In multivariate analyses, independent risks for VTE were age, hospitalization in the past 3 months (OR=13, 95% CI: 6.4 to 27), central venous catheter use in the past 3 months (OR=6.0, 95% CI: 2.3 to 16), and a CD4 count<500 cells/mm (OR=3.0, 95% CI: 1.2 to 7.8).

CONCLUSIONS

The incidence of VTE in our cohort is similar to that reported in other cohorts of patients with HIV. Recent hospitalization was the risk factor most strongly associated with VTE.

Association between cytomegalovirus infection and venous thromboembolism

It has been suggested that cytomegalovirus (CMV) infection may be associated with thrombosis in immunocompromised patients. In addition, an association between CMV infection and thrombotic events in immunocompetent hosts has been sporadically reported. We report on 1 immunocompromised and 8 immunocompetent adults who were admitted to a tertiary medical center and experienced a venous thromboembolic event during CMV infection. None reported previous thromboembolic events. All patients were diagnosed as suffering from acute CMV infection. Seven of the patients had vein thromboses. Significant additional thrombophilia was identified in 5 patients; 1 had 15.3 U/mL anti-cardiolipin IgM antibodies (elevated >7), 2 others were not evaluated for genetic procoagulant tendency. The exact nature of the procoagulant effect of CMV has not yet been clarified. Even though these mechanistic studies are incomplete, we suggest that from the clinical perspective, the presence of CMV infection should be considered a possible risk factor for thrombophilia, justifying a high index of suspicion for possible thrombotic events and subsequent decisions regarding prophylactic anticoagulation.