Detecting retroviral sequences in chronic fatigue syndrome

XMRV or xenotropic murine leukemia virus-related retrovirus, a recently discovered retrovirus, has been linked to both prostate cancer and chronic fatigue syndrome (CFS). Recently, the teams of Drs. Shyh-Ching Lo and Harvey Alter discovered the presence of sequences closely related to XMRV in the blood of 86.5% of patients with CFS [1]. These findings are important because since the initial discovery of XMRV in CFS, several studies have failed to find XMRV in specimens collected from CFS patients. While the current study also did not find XMRV in CFS, Lo et al. did detect sequences that belong to polytropic mouse endogenous retroviruses (PMV), which share considerable similarity with XMRV. Criteria for future studies that will help bring greater clarity to the issue of retroviral sequences in CFS are proposed below.     

No evidence of XMRV infection in immunocompromised patients and HIV-positive individuals from Germany

Background  

Xenotropic murine leukaemia virus-related virus (XMRV) has been detected in patients with prostate cancer and chronic fatigue syndrome (CFS). The detection of XMRV in healthy individuals has raised concern about a possible virus transmission by blood products. However, recent studies challenge the association between XMRV and human disease. This study investigated whether or not XMRV is present in patients with altered immune function and individuals at increased risk of blood-borne viral infections in Germany.     

Failure to detect xenotropic murine leukemia virus-related virus in blood of individuals at high risk of blood-borne viral infections

A xenotropic murine leukemia virus-related virus (XMRV) has recently been reported in association with prostate cancer and chronic fatigue syndrome, with a prevalence of up to 3.7% in the healthy population. We looked for XMRV in 230 patients with human immunodeficiency virus type 1 or hepatitis C infection. XMRV was undetectable in plasma or peripheral blood mononuclear cells by polymerase chain reaction targeting XMRV gag or env. T cell responses to XMRV Gag were undetectable in peripheral blood mononuclear cells by ex vivo gamma interferon enzyme-linked immunospot assay. In our cohorts, XMRV was not enriched in patients with blood-borne or sexually transmitted infections from the United Kingdom and Western Europe.     

Prevalence of xenotropic murine leukemia virus-related virus infection in different risk populations in Spain

Human infection with the xenotropic murine leukemia virus-related virus (XMRV) has been associated controversially with prostate cancer and chronic fatigue syndrome. Information is lacking about the mechanisms of transmission and potential risk groups for XMRV infection. Plasma and peripheral blood mononuclear cells (PBMCs) from individuals with retroviral infections, chronic viral hepatitis, autoimmune diseases, prostate cancer, chronic fatigue syndrome, and blood donors were tested for XMRV markers. Antibodies to XMRV proteins p15E and gp70 were examined using research assays. DNA extracted from PBMCs was tested for the presence of XMRV gag and env sequences. A total of 1103 specimens belonging to individuals with chronic fatigue syndrome and/or fibromyalgia (437), prostate cancer (69), HIV-1 (149), HTLV-1/2 (31), chronic hepatitis B (81), chronic hepatitis C (72), autoimmune diseases (18), and blood donors (246) were examined. Overall, three samples (0.3%) were p15E seroreactive (two HTLV-1 and one HCV patient). Another 15 (1.4%) were gp70 seroreactive (six chronic fatigue syndrome-fibromyalgia, four blood donors, two HIV-1, one prostate cancer, one HBV, and one HCV). Four specimens were initially positive for XMRV gag sequences, but none could be confirmed by repeated testing. In summary, no evidence of XMRV infection was found in populations with retroviral and viral hepatitis infections in Spain. Likewise, XMRV was not recognized in patients with autoimmune diseases, chronic fatigue syndrome-fibromyalgia, prostate cancer, or healthy blood donors.     

Susceptibility of xenotropic murine leukemia virus-related virus (XMRV) to retroviral restriction factors

Xenotropic murine leukemia virus-related virus (XMRV) is a recently discovered gammaretrovirus that has been linked to prostate cancer and chronic fatigue syndrome. This virus is therefore an important potential human pathogen and, as such, it is essential to understand its host cell tropism. Intriguingly, infectious virus has been recovered from patient-derived peripheral blood mononuclear cells. These cells express several antiviral restriction factors that are capable of inhibiting the replication of a wide range of retroviruses, including other gamma retroviruses. This raises the possibility that, similar to HIV, XMRV may have acquired resistance to restriction. We therefore investigated the susceptibility of XMRV to a panel of different restriction factors. We found that both human APOBEC3 and tetherin proteins are able to block XMRV replication. Expression of human TRIM5α, however, had no effect on viral infectivity. There was no evidence that XMRV expressed countermeasures to overcome restriction. In addition, the virus was inhibited by factors from nonhuman species, including mouse Apobec3, tetherin, and Fv1 proteins. These results have important implications for predicting the natural target cells for XMRV replication, for relating infection to viral pathogenicity and pathology, and for the design of model systems with which to study XMRV-related diseases.     

Xenotropic murine leukemia virus-related virus proviral DNA not detected in blood samples donated in Japan

The xenotropic murine leukemia virus-related virus (XMRV) was first described as a novel human gammaretrovirus in prostate tumor tissues and was reported to be found in blood, suggesting the possibility of XMRV transmission via blood transfusion. The gag and env regions of the XMRV proviral DNA that were detected 1,030 blood samples collected from the greater Tokyo area were examined by real-time PCR analysis. However, XMRV infection was not found in the samples; this suggested that the risk of XMRV transmission via transfusion is very low in Japan.     

Detection of MLV-related virus gene sequences in blood of patients with chronic fatigue syndrome and healthy blood donors

Chronic fatigue syndrome (CFS) is a serious systemic illness of unknown cause. A recent study identified DNA from a xenotropic murine leukemia virus-related virus (XMRV) in peripheral blood mononuclear cells (PBMCs) from 68 of 101 patients (67%) by nested PCR, as compared with 8 of 218 (3.7%) healthy controls. However, four subsequent reports failed to detect any murine leukemia virus (MLV)-related virus gene sequences in blood of CFS patients. We examined 41 PBMC-derived DNA samples from 37 patients meeting accepted diagnostic criteria for CFS and found MLV-like virus gag gene sequences in 32 of 37 (86.5%) compared with only 3 of 44 (6.8%) healthy volunteer blood donors. No evidence of mouse DNA contamination was detected in the PCR assay system or the clinical samples. Seven of 8 gag-positive patients tested again positive in a sample obtained nearly 15 y later. In contrast to the reported findings of near-genetic identity of all XMRVs, we identified a genetically diverse group of MLV-related viruses. The gag and env sequences from CFS patients were more closely related to those of polytropic mouse endogenous retroviruses than to those of XMRVs and were even less closely related to those of ecotropic MLVs. Further studies are needed to determine whether the same strong association with MLV-related viruses is found in other groups of patients with CFS, whether these viruses play a causative role in the development of CFS, and whether they represent a threat to the blood supply.     

XMRV is present in malignant prostatic epithelium and is associated with prostate cancer,especially high-grade tumors

Xenotropic murine leukemia virus–related virus (XMRV) was recently discovered in human prostate cancers and is the first gammaretrovirus known to infect humans. While gammaretroviruses have well-characterized oncogenic effects in animals, they have not been shown to cause human cancers. We provide experimental evidence that XMRV is indeed a gammaretrovirus with protein composition and particle ultrastructure highly similar to Moloney murine leukemia virus (MoMLV), another gammaretrovirus. We analyzed 334 consecutive prostate resection specimens, using a quantitative PCR assay and immunohistochemistry (IHC) with an anti-XMRV specific antiserum. We found XMRV DNA in 6% and XMRV protein expression in 23% of prostate cancers. XMRV proteins were expressed primarily in malignant epithelial cells, suggesting that retroviral infection may be directly linked to tumorigenesis. XMRV infection was associated with prostate cancer, especially higher-grade cancers. We found XMRV infection to be independent of a common polymorphism in the RNASEL gene, unlike results previously reported. This finding increases the population at risk for XMRV infection from only those homozygous for the RNASEL variant to all individuals. Our observations provide evidence for an association of XMRV with malignant cells and with more aggressive tumors.     

Origin of XMRV and its demise as a human pathogen associated with chronic fatigue syndrome

Retroviruses are well known pathogens of mammals, birds and fish. Their potential to induce cancer in chickens was already described almost 100 years ago and murine retroviruses have been a subject of study for 50 years. The first human retroviruses, HTLV and HIV, were discovered more than 30 years ago, surprising researchers and physicians by the profound differences in the diseases they cause. HTLV-1 is able to induce, after decades of infection, lymphomas/leukemia or neuroimmune disorders whereas untreated HIV infection leads almost inevitably to AIDS. The recently described XMRV (xenotropic murine leukemia virus-related virus) appeared to possess many of the features known for HTLV and was regarded by some to be the third human retrovirus. However, recent publications by Knox et al. and Paprotka et al. have shed new light on this gammaretrovirus. Knox and colleagues clearly demonstrate that XMRV is absent in patients belonging to a chronic fatigue syndrome cohort who had previously been reported to be XMRV-positive. This supports the growing suspicion that laboratory contamination was responsible for the postulated link between XMRV and the disease. Furthermore, Paprotka et al's identification of XMRV's origin and the phylogenetic analysis of known XMRV sequences are further nails in the coffin to the notion that XMRV is a clinically relevant infectious human retrovirus.     

Xenotropic murine leukemia virus-related virus prevalence in patients with chronic fatigue syndrome or chronic immunomodulatory conditions

We investigated the prevalence of xenotropic murine leukemia virus-related virus (XMRV) among 293 participants seen at academic hospitals in Boston, Massachusetts. Participants were recruited from the following 5 groups of patients: chronic fatigue syndrome (n = 32), human immunodeficiency virus infection (n = 43), rheumatoid arthritis (n = 97), hematopoietic stem-cell or solid organ transplant (n = 26), or a general cohort of patients presenting for medical care (n = 95). XMRV DNA was not detected in any participant samples. We found no association between XMRV and patients with chronic fatigue syndrome or chronic immunomodulatory conditions.     

XMRV and prostate cancer--a 'final' perspective

XMRV was first described in 2006, when it was identified in samples isolated from prostate cancer tissues. However, studies have since shown that XMRV arose in the laboratory and was formed by genetic recombination between two viral genomes carried in the germline DNA of mice used during serial transplantation of the CWR22 prostate cancer xenograft. These new findings strongly imply that XMRV does not circulate in humans, but is only present in the laboratory. Thus, there is no reason to believe that it has any role in the etiology of prostate cancer or other diseases.     

Increased Risk of Chronic Fatigue Syndrome Following Atopy: A Population-Based Study

Several hypotheses have been proposed to explain the etiopathogenesis of chronic fatigue syndrome (CFS), including immune dysregulation. However, few population-based prospective cohort studies have been conducted on CFS and atopy. We investigated the relationship between atopy and CFS by using a population-based cohort study.In this prospective, population-based cohort study of the National Health Insurance Research Database, we identified 42,558 patients with atopy and 170,232 patients without atopy from 2005 to 2007 with follow-up to 2011. The incidence rates and risks for CFS were estimated using Cox proportion hazards regression.The overall incidence rate of CFS was higher in the atopy cohort compared with the nonatopy cohort (1.37 versus 0.87 per 1000 person-year), with an adjusted hazard ratio of 1.48 (95% confidence interval 1.30–1.69). The risk of CFS in the atopy cohort increased 1.47- to 1.50-fold for each nonexisting comorbidity. Patients with numerous atopic symptoms exhibited a biological gradient of increasing risk for CFS, and the risk changed significantly after adjustment for age, sex, and comorbidities, increasing from 1.46- to 2.59-fold.We revealed that atopy is associated with CFS, particularly in patients with numerous atopic syndromes. The actual mechanism for CFS development in patients with atopy remains unclear and requires further investigation. We recommend researching the subsequent fatigue symptom in patients with atopy, particularly those with multiple atopic syndromes.     

Mycoplasma blood infection in chronic fatigue and fibromyalgia syndromes

Chronic fatigue syndrome (CFS) and fibromyalgia syndrome (FMS) are characterised by a lack of consistent laboratory and clinical abnormalities. Although they are distinguishable as separate syndromes based on established criteria, a great number of patients are diagnosed with both. In studies using polymerase chain reaction methods, mycoplasma blood infection has been detected in about 50% of patients with CFS and/or FMS, including patients with Gulf War illnesses and symptoms that overlap with one or both syndromes. Such infection is detected in only about 10% of healthy individuals, significantly less than in patients. Most patients with CFS/FMS who have mycoplasma infection appear to recover and reach their pre-illness state after long-term antibiotic therapy with doxycycline, and the infection can not be detected after recovery. By means of causation and therapy, mycoplasma blood infection may permit a further subclassification of CFS and FMS. It is not clear whether mycoplasmas are associated with CFS/FMS as causal agents, cofactors, or opportunistic infections in patients with immune disturbances. Whether mycoplasma infection can be detected in about 50% of all patient populations with CFS and/or FMS is yet to be determined.     

Liver transplantation for hepatocellular carcinoma in the world: the Taiwan experience

Liver transplantation (LT) has been regarded as “potentially curative” in a cirrhotic patient with hepatocellular carcinoma (HCC) because it removes the cancer and eradicates the cirrhosis. In Taiwan, HCC ranks first among the leading causes of cancer mortality in males and 4th in females. The most common causes are chronic hepatitis B virus-related cirrhosis, hepatitis C virus-related cirrhosis, and combined hepatitis B and C virus-related cirrhosis. The aggregate lifetime cost of hepatitis and HCC constitutes a significant burden on the Taiwanese health-care system. The reported overall (living-donor LT and deceased donor LT) 1- and 3-year survival rates for HCC after LT in Taiwan ranged from 86 to 98% and 61 to 96%, respectively. Microscopic vascular invasion did not influence the outcome of patients, but high alpha-fetoprotein levels >200 ng/ml may be a risk factor for HCC recurrence after transplant.     

Cancer family syndrome. Genetic analysis of 22 Finnish kindreds

The genetic properties and the frequency of cancer family syndrome (CFS) were evaluated on the basis of 22 kindreds identified in Finland by investigating the family histories of young patients with colorectal carcinoma. These families had 196 members with malignancies: 120 colorectal (61%), 30 undefined intraabdominal (15%), 20 endometrial (10%), 7 gastric (4%), 5 biliary tract (3%) adenocarcinomas, and 14 (7%) other cancers. The present CFS patients represented 0.4% of all colorectal cancers diagnosed in Finland during 1961-1980, and the estimated minimum frequency of CFS was 4-4.7 X 10(-5) (1 in 25,100-21,400). An autosomal dominant pattern of genetic transmission for colorectal cancer was demonstrated through two to four generations, but the trait was also transferred by mothers with uterine carcinoma. The highest incidence of colorectal carcinoma occurred between 40 and 49 yr of age (15% per decade), and the cumulative risk in the descendants increased to 50% at 69 yr. The penetrance of CFS was 0.5-0.9. The analysis suggest that heredity is more significant in the etiology of colorectal cancer than has been previously believed. Identification of CFS seems to provide a good opportunity for screening the descendants of affected patients for colorectal cancer.     

Melatonin levels in women with fibromyalgia and chronic fatigue syndrome

OBJECTIVE: Fibromyalgia (FM) and chronic fatigue syndrome (CFS) are stress associated disorders mainly affecting women. FM is characterized primarily by widespread musculoskeletal pain, and CFS by profound debilitating fatigue, but there is considerable overlap of clinical symptoms between these 2 syndromes. Neuroendocrine abnormalities have been noted in both FM and CFS and desynchronization of circadian systems has been postulated in their etiology. The pineal hormone melatonin is involved in synchronizing circadian systems and the use of exogenous melatonin has become widespread in patients with FM and CFS. METHODS: We examined the characteristics and relationship of melatonin and cortisol levels in premenopausal women with FM (n = 9) or CFS (n = 8), compared to age and menstrual cycle phase matched controls. Blood was collected from an indwelling intravenous catheter every 10 min over 24 h, and plasma melatonin and cortisol were determined by radioimmunoassay at 60 and 10 min intervals, respectively. RESULTS: Night time (23:00-06:50) plasma melatonin levels were significantly higher in FM patients compared to controls (p<0.05), but there was no significant difference in melatonin levels between CFS patients and controls. No differences in the timing of cortisol and melatonin secretory patterns and no internal desynchronization of the 2 rhythms were found in either patient group, compared to controls. CONCLUSION: Raised plasma melatonin concentrations have been documented in several other conditions that are associated with dysregulation of neuroendocrine axes. Increased melatonin levels may represent a marker of increased susceptibility to stress induced hypothalamic disruptions. These data indicate that there is no rationale for melatonin replacement therapy in patients with FM and CFS.     

Paraneoplastic syndromes in prostate cancer

Prostate cancer is the second most common urological malignancy to be associated with paraneoplastic syndromes after renal cell carcinoma. These syndromes tend to occur in the setting of late stage and aggressive tumors with poor overall outcomes. Recognition of these syndromes is clinically important as it might lead to the detection of underlying malignancy and impact on the treatment options available. The literature features around 100 cases of paraneoplastic syndromes associated with prostate cancer and these include endocrine manifestations, neurological entities, dermatological conditions, and other syndromes. Over 70% of cases document the syndrome as the initial clinical manifestation of prostate cancer, while in just under 20% the syndrome was an initial sign of disease progression to the castrate-resistant state. The vast majority of cases involved advanced metastatic malignancy. The syndromes generally resolve upon institution of treatment for the underlying prostate cancer, but some syndromes require specific therapies. Some syndromes are associated with serum markers that are readily detectable and demonstration of these putative markers within prostate cancer tissue at an individual level would firmly link the paraneoplastic syndrome with its underlying prostatic malignancy. The causes of paraneoplastic syndromes in prostate cancer are incompletely understood, and further research into their biology might shed more light on the complex molecular mechanisms that underpin prostate cancer and its lethal potential.     

Mechanisms of prostate cancer progression to androgen independence

Prostate cancer is a major health problem in the United States and worldwide. In 2007, more than 27,000 men were estimated to have died from prostate cancer in the United States alone. Although important advances have been made in the diagnosis and treatment of prostate cancer, therapies focused on the removal or inhibition of androgen action remain the most important components of therapy for individuals with metastatic disease. Despite the application of such modalities, the vast majority of patients with metastatic disease progress with a median survival of less than 2 years. A number of different mechanisms have been identified that may potentially contribute to the progression of prostate cancer. These insights suggest that signaling via the androgen receptor (AR) -- either via alternate signaling pathways impinging on the AR or through the in situ formation of androgens within progressive tumors -- is an important contributor to such progressive disease. It is anticipated that such mechanistic insights will lead to the development of useful new therapies in the future.     

Chronic fatigue syndrome

During the past two decades, there has been heated debate about chronic fatigue syndrome (CFS) among researchers, practitioners, and patients. Few illnesses have been discussed so extensively. The existence of the disorder has been questioned, its underlying pathophysiology debated, and an effective treatment opposed; patients' organisations have participated in scientific discussions. In this review, we look back on several controversies over CFS with respect to its definition, diagnosis, pathophysiology, and treatment. We review issues of epidemiology and clinical manifestations, focusing on the scientific status of CFS. Modern neuroscience and genetics research offer interesting findings for new hypotheses on the aetiology and pathogenesis of the illness. We also discuss promising future issues, such as psychopathophysiology and mechanisms of improvement, and suggest multidisciplinary prospective studies of CFS and fatigue in the general population. These studies should pay particular attention to similarities to and differences from functional somatic syndromes and other fatiguing conditions.