Konstance K. Knox

No Evidence of Murine-Like Gammaretroviruses in CFS Patients Previously Identified as XMRV-Infected

Chronic fatigue syndrome patients reported previously to be XMRV-infected show no signs of the virus in an independent evaluation. Members of the gammaretroviruses—such as murine leukemia viruses (MLVs), most notably XMRV [xenotropic murine leukemia virus (X-MLV)–related virus—have been reported to be present in the blood of patients with chronic fatigue syndrome (CFS). We evaluated blood samples from 61 patients with CFS from a single clinical practice, 43 of whom had previously been identified as XMRV-positive. Our analysis included polymerase chain reaction and reverse transcription polymerase chain reaction procedures for detection of viral nucleic acids and assays for detection of infectious virus and virus-specific antibodies. We found no evidence of XMRV or other MLVs in these blood samples. In addition, we found that these gammaretroviruses were strongly (X-MLV) or partially (XMRV) susceptible to inactivation by sera from CFS patients and healthy controls, which suggested that establishment of a successful MLV infection in humans would be unlikely. Consistent with previous reports, we detected MLV sequences in commercial laboratory reagents. Our results indicate that previous evidence linking XMRV and MLVs to CFS is likely attributable to laboratory contamination.

Human herpesvirus-6 in liver transplant recipients: role in pathogenesis of fungal infections, neurologic complications, and outcome.

BACKGROUND The clinical impact and relevance of human herpesvirus-6 (HHV-6) infection in liver transplant recipients, has not been fully discerned. METHODS A prospective study of 80 consecutive liver transplant recipients was performed using surveillance cultures for HHV-6 at weeks 2, 3, 4, and 6 after transplantation. Viral isolation was used for the detection of HHV-6. RESULTS HHV-6 infection occurred in 39% (31 of 80) of the patients. Patients with HHV-6 infection were more likely to have hepatocellular carcinoma as underlying liver disease (P=.09). Mental status changes of unidentifiable etiology were significantly more likely to occur in patients with HHV-6 compared with those without (26%, 9 of 31 vs. 6%, 3 of 49, P=.008). HHV-6 infection was an independent predictor of invasive fungal infections (odds ratio 8.3, 95% confidence interval, 1.2-58.0, P=.03). A significant association between HHV-6 infection and CMV infection after transplantation, CMV recipient and donor serostatus, rejection, or fever of unknown origin, could not be documented. Mortality at last follow-up in patients with HHV-6 infection (29%, 9 of 31) was significantly greater than those without HHV-6 (6%, 3 of 49, P=.008). CONCLUSIONS Central nervous system complications of unknown etiology after liver transplantation may be related to HHV-6 infection. HHV-6 viremia was an independently significant predictor of invasive fungal infections and was associated with late mortality in liver transplantation recipients.

Human Herpesvirus 6 and Multiple Sclerosis: Systemic Active Infections in Patients with Early Disease

By means of immunohistochemical staining, cells actively infected with human herpesvirus 6 (HHV-6) were found in central nervous system tissues from 8 (73%) of 11 patients with definite multiple sclerosis (MS). Interestingly, 17 (90%) of 19 tissue sections showing active demyelination were positive for HHV-6-infected cells compared with only 3 (13%) of 23 tissue sections free of active disease (P<.0001). Central nervous system tissues from 2 of 28 normal persons and patients with other inflammatory demyelinative diseases were positive for HHV-6-infected cells (P<.0001), and the 2 positive cases were diagnosed as having HHV-6 leukoencephalitis. By use of a rapid culture assay, blood samples from 22 (54%) of 41 patients with definite MS were found to contain active HHV-6 infections, compared with 0 of 61 normal controls (P<.0001). No significant difference was found between HHV-6 viremia-positive and HHV-6 viremia-negative MS patients with respect to type of disease (relapsing/remitting or progressive). In contrast, patients with active HHV-6 viremia were significantly younger and had shorter durations of disease than did HHV-6 viremia-negative patients.

Subacute leukoencephalitis caused by CNS infection with human herpesvirus-6 manifesting as acute multiple sclerosis

Several recent reports have documented the neuroinvasiveness of human herpesvirus-6 (HHV-6) in infants with primary HHV-6 infections, in children and adults with AIDS, in recipients of bone marrow transplants, and in immunologically intact adults and children. CNS infections with HHV-6 can be subacute and are frequently associated with diffuse or multifocal demyelination. We analyzed the CNS tissues of a young woman who died of a demyelinative disease, which was clinically and histopathologically diagnosed as acute multiple sclerosis, for active HHV-6 infection by immunohistochemical staining. The tissues contained a dense and disseminated active HHV-6 infection that was intimately related to the pathologic changes present. NEUROLOGY 1996;47: 145-148

Impact of human herpesvirus-6 on the frequency and severity of recurrent hepatitis C virus hepatitis in liver transplant recipients

A role of tumor necrosis factor‐alpha (TNF‐α) In the immunopathogenesis of hepatitis C virus (HCV) infection has been proposed. The novel herpes virus, human herpes virus‐6 (HHV‐6), is amongst the most potent inducers of cytokines, including TNF‐α. The impact of HHV‐6 viremia on the progression of recurrent HCV hepatitis was assessed in 51 HCV‐positive liver transplant recipients. The frequency of recurrent HCV hepatitis did not differ between patients with HCV viremia (47.6%, 10/21) as compared with those without HCV viremia (46.7%, 14/30, p=0.9). However, the patients with HHV‐6 viremia had a significantly higher fibrosis score upon HCV recurrence than those without HHV‐6 viremia (mean 1.5 vs. 0.3, p=0.01). An association between cytomegalovirus (CMV) viremia and HCV recurrence was not documented; 50% (15/30) of the patients with CMV viremia and 42.8% (9/21) of those without CMV viremia had recurrent HCV hepatitis (p > 0.5). Receipt of ganciclovir (administered upon the detection of CMV viremia) was associated with lower total Knodell score (mean 5.2 vs. 6.9, p=0.05) and a trend towards lower fibrosis score (mean 0.44 vs. 1.00, p=0.12) in patients with recurrent HCV hepatitis. Thus, HHV‐6 viremia in HCV‐positive liver transplant recipients identified a subgroup of patients at increased risk for early fibrosis upon HCV recurrence.

Active HHV-6 infection in the lymph nodes of HIV-infected patients: in vitro evidence that HHV-6 can break HIV latency.

Studies published previously by this laboratory have demonstrated that patients with AIDS have widely disseminated, active infections with HHV-6 at the time of their death. However, it remains unclear when in the course of the human immunodeficiency virus (HIV) infection the active HHV-6 infection first appears. To address this question, lymph node biopsies from 10 HIV-infected patients were analyzed for active human herpesvirus 6 (HHV-6) infections by immunohistochemical staining. Eight of the biopsies carried the histologic diagnosis of follicular hyperplasia; the other two were characterized as having follicular involution with histiocytosis and reactive lymphadenitis. In total, 10 of 10 (100%) of the lymph nodes studied contained cells productively infected with HHV-6; in contrast, three lymph nodes with follicular hyperplasia and four normal lymph nodes from patients not infected with HIV were negative for HHV-6 infection. Of special note, the absolute CD4+ lymphocyte counts of 75% (6/8) of the HIV-infected individuals included in these studies were > 200/mm3 at the time of their lymph node biopsy. The A variant of HHV-6 was found to be the predominant form of the virus present in the lymph node biopsies from all of these HIV-infected patients, and in vitro studies demonstrated that exposure of monocytic cells carrying latent HIV to HHV-6A resulted in massive upregulation of HIV replication from latency. Thus, active HHV-6 infections appear relatively early in the course of HIV disease, and in vitro studies suggest that the A variant of HHV-6 is capable of breaking HIV latency, with the potential for helping to catalyze the progression of HIV infections to AIDS.

Rapid Communication: Active Human Herpesvirus (HHV-6) Infection of the Central Nervous System in Patients with AIDS

White matter disease is a relatively common neuropathological change observed in the central nervous system (CNS) tissues of patients with AIDS at autopsy. This disease ranges from small foci of myelin loss to extensive areas of demyelination. In the studies reported here, four of six unselected adult patients with AIDS had areas of demyelination in their CNS tissues at the time of their deaths. In the tissues examined, the severity of the demyelinative disease varied among the patients from a single focus of demyelination to essentially confluent loss of myelin in subcortical white matter and other CNS structures. The demyelinative disease in the brains of these patients was closely associated with active HHV-6 infection. The infected cells were present only in areas of demyelination, and they were never observed in tissue areas free of pathological changes. The HHV-6-associated neuropathology observed in the brains of these patients was identical to that described in an adult bone marrow transplant (BMT) patient with fatal HHV-6 encephalitis. Thus HHV-6-induced white matter disease appears to be a distinct pathological syndrome. Pathogenic mechanisms involved in this disease are unknown. However, the existence of HHV-6 leukoencephalopathy in a BMT patient demonstrates the potential for HHV-6 leukoencephalopathy in a BMT patient demonstrates the potential for HHV-6 to cause this syndrome without need for a cofactor or copathogen such as HIV.

Serologic Evidence of Powassan Virus Infection in Patients with Suspected Lyme Disease1

Powassan virus (POWV) lineage II is an emerging tickborne flavivirus with an unknown seroprevalence in humans. In a Lyme disease–endemic area, we examined the seroreactivity to POWV in 2 patient cohorts and described the clinical features of the POWV-seroreactive patients. POWV disease might be less neuroinvasive than previously thought.

Human herpesvirus-6-associated malignant lymphoma in a bone marrow transplant recipient

BACKGROUND Human herpesvirus-6 (HHV-6), the sixth member of the herpesvirus family, can infect and replicate in human hematopoetic cell lines and can cause various illnesses in humans. HHV-6 has been suggested to be linked to various lymhoproliferative disorders. In vitro studies have demonstrated the oncogenic potential of HHV-6. The role of HHV-6 in human lymphomas needs to be examined. OBJECTIVE To determine the involvement of HHV-6 in an immunoblastic lymphoma which developed in a bone marrow transplant patient, who had HHV-6 viremia. STUDY DESIGN Paraffin-embedded lymphoma tissues were examined for the presence of HHV-6 by immunohistochemistry, PCR and in-situ hybridization. This is a case report investigation. RESULTS An acute myelogenous leukemia patient received an allogeneic bone marrow transplant. He developed human herpesvirus-6 (HHV-6) viremia approximately 6 weeks after transplantation and HHV-6 was concurrently isolated from his bone marrow. Soon afterward, a large cell immunoblastic lymphoma was diagnosed. Complications of this tumor subsequently resulted in the patients death. Periaortic lymph nodes and tumor cells infiltrating the liver and kidneys showed the presence of HHV-6 by immunohistochemistry and polymerase chain reaction (PCR). Southern blot analysis of the PCR amplified DNAs confirmed the presence of transforming pZVH14 DNA sequences of HHV-6 in the tumor tissues. Lymph nodes of 6 immunologically intact individuals were negative for HHV-6 by immunohistochemistry and PCR analysis. Tumor tissues were negative for EBV DNA by in situ hybridization with DNA probes specific for the EBV EBER RNAs. CONCLUSION Our data suggest that HHV-6 may be involved in the pathogenesis of some immunoblastic lymphomas.

Development and Validation of a Serologic Test Panel for Detection of Powassan Virus Infection in U.S. Patients Residing in Regions Where Lyme Disease Is Endemic

Approximately 100 cases of POWV disease were reported in the United States over the past 10 years. Most cases have occurred in the Northeast (52) and Great Lakes (45) regions (https://www.cdc.gov/powassan/statistics.html). The prevalence of POWV in ticks and mammals is increasing, and POWV poses an increasing threat in a greater geographical range. In areas of the Northeast and Midwest where Lyme disease is endemic, POWV testing is recommended for patients with a recent tick bite, patients with Lyme disease who have been treated with antibiotics, or patients with a tick exposure who have tested negative for Lyme disease or other tick-borne illnesses and have persistent symptoms consistent with posttreatment Lyme disease. Testing could also benefit patients with tick exposure and unexplained neurologic symptoms and chronic fatigue syndrome (CFS) patients with known tick exposure. Until now, diagnostic testing for Powassan virus has not been commercially available and has been limited to patients presenting with severe, neurologic complications. The lack of routine testing for Powassan virus in patients with suspected tick-borne disease means that little information is available regarding the overall prevalence of the virus and the full spectrum of clinical symptoms associated with infection. As Ixodes scapularis is the tick vector for Powassan virus and multiple other tick-borne pathogens, including the Lyme disease bacterium, Borrelia burgdorferi, the clinical presentations and long-term outcomes of Powassan virus infection and concurrent infection with other tick-borne disease pathogens remain unknown. ABSTRACT Powassan virus (POWV) is an emerging tick-borne arbovirus presenting a public health threat in North America. POWV lineage II, also known as deer tick virus, is the strain of the virus most frequently found in Ixodes scapularis ticks and is implicated in most cases of POWV encephalitis in the United States. Currently, no commercial tests are available to detect POWV exposure in tick-borne disease (TBD) patients. We describe here the development and analytical validation of a serologic test panel to detect POWV infections. The panel uses an indirect enzyme immunoassay (EIA) to screen. EIA-positive samples reflex to a laboratory-developed, POWV-specific immunofluorescence assay (IFA). The analytical sensitivity of the test panel was 89%, and the limit of detection was a plaque reduction neutralization test (PRNT) titer of 1:20. The analytical specificity was 100% for the IgM assay and 65% for the IgG assay when heterologous-flavivirus-positive samples were tested. On samples collected from regions where Lyme disease is endemic, seroprevalence for POWV in TBD samples was 9.4% (10 of 106) versus 2% when tested with non-TBD samples (2 of 100, P = 0.034). No evidence of POWV infection was seen in samples collected from a region where Lyme disease was not endemic (0 of 22). This test panel provides a sensitive and specific platform for detecting a serologic response to POWV early in the course of infection when neutralizing antibodies may not be detectable. Combined with clinical history, the panel is an effective tool for identifying acute POWV infection. IMPORTANCE Approximately 100 cases of POWV disease were reported in the United States over the past 10 years. Most cases have occurred in the Northeast (52) and Great Lakes (45) regions (https://www.cdc.gov/powassan/statistics.html). The prevalence of POWV in ticks and mammals is increasing, and POWV poses an increasing threat in a greater geographical range. In areas of the Northeast and Midwest where Lyme disease is endemic, POWV testing is recommended for patients with a recent tick bite, patients with Lyme disease who have been treated with antibiotics, or patients with a tick exposure who have tested negative for Lyme disease or other tick-borne illnesses and have persistent symptoms consistent with posttreatment Lyme disease. Testing could also benefit patients with tick exposure and unexplained neurologic symptoms and chronic fatigue syndrome (CFS) patients with known tick exposure. Until now, diagnostic testing for Powassan virus has not been commercially available and has been limited to patients presenting with severe, neurologic complications. The lack of routine testing for Powassan virus in patients with suspected tick-borne disease means that little information is available regarding the overall prevalence of the virus and the full spectrum of clinical symptoms associated with infection. As Ixodes scapularis is the tick vector for Powassan virus and multiple other tick-borne pathogens, including the Lyme disease bacterium, Borrelia burgdorferi, the clinical presentations and long-term outcomes of Powassan virus infection and concurrent infection with other tick-borne disease pathogens remain unknown.