Viral hepatitis in a Canadian First Nations community.

Serological markers for hepatitis A (HAV), B (HBV) and C (HCV) were documented in 315 inhabitants (27%) of a central Manitoba First Nations community. Serologic evidence of HAV infection (anti-HAV positive) was almost universal (92%) by the age of 20 years. HBV infection (antibody to hepatitis B core antigen positive) had occurred in only 2.3% of the study population and no chronic carriers were identified. Serological evidence of HCV infection (anti-HCV positive) was documented in 2.2% of the population but ongoing viremia (HCV-RNA positive by polymerase chain reaction) was absent. The results of this study highlight the importance of universal HAV vaccination; likely reflect the efficacy of existing prenatal screening and immunoprophylaxis programs for HBV; and raise the possibility that First Nations peoples have an enhanced ability to spontaneously clear HCV.

Neurovirulence depends on virus input titer in brain in feline immunodeficiency virus infection: evidence for activation of innate immunity and neuronal injury.

Lentiruses cause neurological disease depending on the virus strain and its neurotropism, yet it remains uncertain to what the impact of infectious virus quantity in the brain early in infection is on the subsequent development of neurological disease or neurovirulence. We investigated the relationship between infectious virus input titer and the resulting neurovirulence, using ex vivo and in vivo assays of feline immunodeficiency virus (FIV)-induced neurovirulence. FIV infection of cell cultures and neonatal cats was performed using 10(2.5) (low-titer) or 10(4.5) (high-titer) 50% tissue culture infectious doses (TCID(50))/ml of the neurovirulent FIV strain, V1CSF. Ex vivo neurotoxicity assays revealed that conditioned medium (CM) from feline macrophages infected with high-titer (P <.001) or low-titer (P <.01) V1CSF induced greater neuronal death than CM from mock-infected cells. In vivo, animals infected intracranially with high-titer V1CSF showed neurodevelopmental delays compared to mock-infected animals (P <.001) and animals infected with low-titer V1CSF (P <.02), concurrent with reduced weight gains and greater depletion of CD4+ cells over a 12-week period. Neuropathological changes, including astrogliosis, macrophage activation, and neuronal damage, were evident in V1CSF-infected animals and were viral titer dependent. In vivo magnetic resonance (MR) spectroscopy and proton nuclear magnetic resonance ((1)H-NMR) spectroscopy of tissue extracts revealed evidence of neuronal injury, including reduced N-acetyl aspartate/creatine (P <.05) and increased trimethylamine/creatine (P <.05) ratios, in the frontal cortex of high-titer V1CSF-infected animals compared to the other groups. T2-weighted MR imaging detected increased signal intensities in the frontal cortex and white matter of V1CSF-infected animals relative to controls, which was more evident as viral titer increased (P <.01). The present findings indicate that lentivirus infectious titers in the brain during the early stages of infection determine the severity of neurovirulence, reflected by neurobehavioral deficits, together with neuroradiological and neuropathological findings of activation of innate immunity and neuronal injury.

A causal role for parvovirus B19 infection in adult dermatomyositis and other autoimmune syndromes.

BACKGROUND: Infection with parvovirus B19 (B19) has been associated with connective tissue disease (CTD) stigmata, namely, a systemic lupus erythematosus (SLE)-like illness, seronegative polyarthritis resembling rheumatoid arthritis, and vasculitis. The dermatopathology and pathogenetic basis of such B19-associated CTD-like syndromes have not been elucidated. OBJECTIVE: We attempted to document persistence of the B19 genome in skin lesions of 7 patients with CTD-like symptomatology following B19 infection and to correlate systemic manifestations to dermatopathological findings. METHOD: In 7 prospectively encountered patients in whom history, clinical signs and/or serology supported a diagnosis of CTD in the setting of B19 infection, dermatopathological and clinical features were correlated. Parvovirus B19 viral genome was sought in skin tissue using the polymerase chain reaction (PCR). RESULTS: Two patients had clinical features diagnostic of myopathic dermatomyositis (DM), 1 of whom is still symptomatic 1.5 years after the onset of her illness, and the other has had typical clinical features of DM for a duration of 3.5 years. A 3rd patient with SLE remains symptomatic 4 years after the onset of her illness. A 4th patient has persistent seronegative symmetrical polyarthritis of 6 years' duration and cutaneous lesions of granuloma annulare (GA). The 5th patient has a 1.5-year history of debilitating polyarthritis and cutaneous lesions with overlap features of DM and subacute cutaneous LE (SCLE). The 6th patient has had a persistent folliculocentric necrotizing vasculitis for 3 years. The 7th patient has a 1-year history of microscopic polyarteritis nodosa (PAN) with cutaneous vasculitis and persistent active renal disease. In 4 patients, exposure to children with fifth disease immediately preceded the onset of their CTD. Parvovirus B19 infection was documented serologically in 6 patients with antibodies of IgG subclass in 6 and of IgM subclass in 1. Four of 6 patients questioned had a history of atopy. Skin biopsies from patients with clinical features of SLE or DM demonstrated an interface dermatitis with dermal mucinosis. A necrotizing vasculitis with epithelial pustulation was seen in 2 patients. Interstitial GA-like infiltrates were seen in 5 cases. Immunofluorescent (IF) testing revealed a positive lupus band test (LBT) and epidermal nuclear and vascular staining for IgG and C5b-9 in the SLE patient. One DM patient had a negative LBT in concert with C5b-9 deposition along the dermoepidermal junction (DEJ) and within blood vessels while the other showed endomysial vascular Cs5b-9 deposition. In all patients, skin biopsy material contained B19 genome, which was absent in the serum of 4 patients analyzed. Symptomatic relief followed immunosuppressive and immunomodulatory therapy with agents including prednisone, cyclophosphamide, hydroxychloroquine, non-steroidal anti-inflammatory drugs and etanercept, but no patient has had complete symptom resolution. CONCLUSIONS: Persistent B19 infection may be of pathogenetic importance in certain prototypic CTD syndromes, to which underlying immune dysregulation associated with a blunted IgM response to viral antigen may predispose. Anti-viral therapy might be worthy of consideration since traditional immunosuppressive therapy was unsuccessful in our cases.

The cutaneous manifestations of human parvovirus B19 infection.

The prototypical cutaneous manifestations of human parvovirus B19 (B19) infection include a petechial eruption in a glove and stocking distribution, reticular truncal erythema, and the "slapped cheek" sign. An association with connective tissue disease (CTD) stigmata has recently been made. The clinical and dermatopathologic findings in 14 patients whose skin lesions were accompanied by serological evidence of B19 infection or documentation of B19 genome in lesional skin are presented. The authors encountered skin biopsy specimens from 14 patients who presented with skin eruptions accompanied by clinical signs or serology suggestive of antecedent B19 infection. Clinical findings were correlated to the light microscopic appearance of the lesions and the presence of B19 genome in lesional skin. The study group comprised 9 women, 3 men, and 2 boys. Eruptions characteristic of fifth disease, including the slapped cheek sign, reticulated truncal erythema, and acral petechiae, were present in 3 patients, 1 of whom later developed granuloma annulare. The other patients had atypical clinical presentations comprising an asymptomatic papular eruption (2), an eruption clinically resembling Sweet's syndrome (3), myopathic dermatomyositis (DM) (2), lupus erythematosus (LE)-like syndromes (2), and lower-extremity palpable purpura (2). Skin biopsy specimens in 12 cases showed interstitial histiocytic infiltrates with piecemeal fragmentation of collagen and a mononuclear cell-predominant vascular injury pattern. Other features included an interface dermatitis, eczematous alterations, and papillary dermal edema. Lesions with features of DM or LE also showed mesenchymal mucinosis, whereas a biopsied lesion of palpable purpura showed leukocytoclastic vasculitis (LCV). Immunofluorescent testing showed a positive lupus band test (LBT) with epidermal IgG and C5b-9 decoration in 1 patient with a systemic LE-like illness, whereas the DM patients had negative LBTs and vascular C5b-9 deposition typical for DM. Skin biopsy specimens from 11 patients, including those whose presentations resembled LE and DM, were positive for B19 genome. The dermatopathology of B19 infection suggests tissue injury mediated by delayed-type hypersensitivity, by antibody-dependent cellular immunity directed at microbial antigenic targets in the epidermis and endothelium, and by circulating immune complexes in the setting of LCV. These mechanisms appear to generate a clinical and histopathological picture that recapitulates that of CTD.

Neurovirulence in feline immunodeficiency virus-infected neonatal cats is viral strain specific and dependent on systemic immune suppression.

Feline immunodeficiency virus (FIV) is a lentivirus that causes immune suppression and neurological disease in cats. Among animal viruses, individual viral strains have been shown to be neurovirulent, but the role of viral strain specificity among lentiviruses and its relationship to systemic immune suppression in the development of neurological disease remains uncertain. To determine the extent to which different FIV strains caused neurological disease, FIV V1CSF and Petaluma were compared in ex vivo assays and in vivo. Both viruses infected and replicated in macrophage and mixed glial cell cultures at similar levels, but V1CSF induced significantly greater neuronal death than Petaluma in a neurotoxicity assay. V1CSF-infected animals showed significant neurodevelopmental delay compared to the Petaluma-infected and uninfected animals. Magnetic resonance spectroscopy studies of frontal cortex revealed significantly reduced N-acetyl aspartate/creatine ratios in the V1CSF group compared to the other groups. Cyclosporin A treatment of Petaluma-infected animals caused neurodevelopmental delay and reduced N-acetyl aspartate/creatine ratios in the brain. Reduced CD4(+) and CD8(+) cell counts were observed in the V1CSF-infected group compared to the uninfected and Petaluma-infected groups. These findings suggest that neurodevelopmental delay and neuronal injury is FIV strain specific but that systemic immune suppression is also an important determinant of FIV-induced neurovirulence.

Association of phenotypic changes in B cell lymphocytes and plasma viral load in human immunodeficiency virus-infected patients.

Many B cell abnormalities have been reported in human immunodeficiency virus (HIV)-infected patients, including changes in the expression of mu, gamma, and CD22 molecules on the cell surface. Phenotypic changes in these markers on B cells isolated from HIV-seropositive patients with high or low levels of plasma viremia were measured. The phenotypic changes in B cells isolated from such patients were compared with the markers on B cells isolated from HIV-seronegative individuals using three-color flow cytometry. HIV patients showed a reduction in the proportion of mature B cells isolated from peripheral blood mononuclear cells compared with B cells isolated from HIV-seronegative individuals. An increase in the proportion of B cells expressing both mu and gamma molecules on the cell surface was also seen in association with high-HIV plasma viremia. A low plasma viral load was accompanied by a reduction in the proportion of B cells expressing both mu and gamma molecules to a level comparable to those seen in HIV-seronegative individuals. HIV-seropositive individuals demonstrated an increase in the proportion of committed B cells, as indicated by an increase in the proportion of B cells expressing gamma molecules. This observation may explain the poor humoral response of HIV seropositive patients to neo-antigens. Our results demonstrate that phenotypic changes indicative of in vivo B cell activation and an increase in immature cells are associated with HIV infection, particularly with a high plasma viral load. Phenotypic changes in B cell markers may correlate with functional deficits of B cells.

Comparison of salivary and serum enzyme immunoassays for the diagnosis of Helicobacter pylori infection.

Infection with Helicobacter pylori has been established as an important risk factor for the development of peptic ulcer disease, gastritis and gastric cancer. The diagnosis of H pylori infection can be established by invasive or noninvasive techniques. Two noninvasive enzyme immunoassays (EIAs) for antibody detection - HeliSal and Pylori Stat - were compared with histology. Both assays detect immunoglobulin (Ig) G directed against purified H pylori antigen. The test populations consisted of 104 consecutive patients scheduled for upper gastrointestinal endoscopy. Of these patients, 97 (93%) had symptoms compatible with peptic ulcer disease. Saliva and serum were collected simultaneously at the time of endoscopy. Salivary EIA had a sensitivity of 66%, specificity of 67%, positive predictive value of 67% and negative predictive value of 66% compared with the serum EIA, where the results were 98%, 48%, 64% and 96%, respectively. Although the salivary EIA is an appealing noninvasive test, it was not a sensitive and specific assay. The serum EIA also lacked specificity, but was highly sensitive with a good negative predictive value. Although a negative serum EIA rules out H pylori infection, a positive result must be interpreted in the clinical context and confirmed with a more specific measure.

Varicella zoster antibodies after herpes zoster, varicella and multiple sclerosis.

BACKGROUND: We previously showed that Manitoba Hutterites seek physician care for varicella zoster virus infection significantly less than non-Hutterites. The current study was undertaken to measure varicella zoster virus seroprevalence for Hutterite and non-Hutterite controls. METHODS: Blood was obtained from 315 Hutterites and 259 similar age and sex controls at the time of blood donations to The Canadian Red Cross Society. The controls were from the same or a contiguous postal code area and were collected at the same time as the Hutterite samples. The immune status of the specimens was determined by the ELISA method (enzyme linked immunosorbent assay). RESULTS: Twenty-eight per cent of 315 Hutterites had no immunity and an additional 25% had only marginal immunity. Among the 259 controls, 10% had no immunity and an additional 10% had only marginal immunity (p < .0001). CONCLUSIONS: Manitoba Hutterites have significantly decreased seroprevalence to varicella zoster virus infection. This study of serum varicella zoster virus antibodies verifies a previous population based study that demonstrated the relative rarity of varicella and herpes zoster among a particular population group.

Juvenile dermatomyositis in a child infected with human parvovirus B19.

We report a case of juvenile dermatomyositis in which clinical onset occurred soon after infection with human parvovirus B19. To the best of our knowledge an association between juvenile dermatomyositis and human parvovirus B19 has not been previously reported. Parvovirus infection has been associated with several autoimmune diseases, and the findings in the case we describe raise the possibility that parvovirus may induce juvenile dermatomyositis, although we could not demonstrate a causal relationship.

Development of oligonucleotide primers and probes against structural and regulatory genes of human immunodeficiency virus type 1 (HIV-1) and their use for amplification of HIV-1 provirus by using polymerase chain reaction.

The polymerase chain reaction is a powerful technique for amplifying a few copies of double-stranded genetic material to millions of copies in a few hours. The sensitivity and specificity of the polymerase chain reaction technique depend to some extent on the nucleotide sequences of the oligonucleotide primer pair used in the amplification. We report new oligonucleotide primers and probes which can be used for the amplification and detection of human immunodeficiency virus type 1 provirus sequences of not only structural but also regulatory genes. These primers are very sensitive and specific and can be used for the detection of African and North American strains of human immunodeficiency virus type 1.

Infectivity-deficient vesicular stomatitis virus produced in the presence of interferon has a functional virion core.

Interferon induces two antiviral actions against vesicular stomatitis virus by (i) inhibiting viral protein synthesis which leads to a reduction in virion production, and (ii) producing progeny which are deficient in infectivity (VSVIF). At low or physiological concentrations of interferon, while the virion production was decreased by less than 10-fold, the virion infectivity yield was suppressed more than 1000-fold. The VSVIF was found to be deficient (quantitatively) in envelop glycoprotein G and protein M. Tryptic peptide mapping indicated that there was no detectable structural abnormality in the G, M, and N proteins of VSVIF. The virion cores, lacking only the envelop G protein, isolated from VSVIF and control VSV have essentially identical specific infectivity. This indicated that the virion proteins L, N, NS, and M, as well as viral RNA that make up the virion core, must be functionally normal, and the observed deficiency in G protein was likely to be the cause of the functional deficiency of the virion. Low concentrations of DEAE-dextran, which is known to partially overcome the virion's dependence on the G protein for adsorption to the cell during infection, were found to enhance the infectivity of VSVIF more than the control virion. These results together indicated that the loss of infectivity in the VSVIF was due to the deficiency of the surface glycoprotein G.

Interferon induces the production of membrane protein-deficient and infectivity-defective vesicular stomatitis virions through interference in the virion assembly process.

The reduced rate of synthesis, maturation and degradation as well as the level of accumulation of the intracellular virus proteins in VSV-infected cells may account for the overall reduction (less than 10-fold) of progeny virion yield due to interferon (IFN); however, the deficiency of the virions proteins, G and M, which apparently caused a drastic loss of infectivity of these progeny virions (about 1000-fold) cannot be easily explained, because the concentrations of G and M proteins relative to other virus proteins were not reduced in the cell. In fact, intracellular M protein was significantly increased. Moreover, the virus proteins in IFN-treated and control cells were synthesized and accumulated in large excess of the amount incorporated into the released virions. The reduction in the intracellular activity of GlcNac-P-P-Dol transferase did not appear to play a direct role in the antiviral mechanism in this system. Our results, however, do suggest that the deficiency of G and M proteins in the virion is related to specific inhibition of the incorporation of either or both of these proteins in the virus assembly process.