Virus Antibody Titers Research Articles

Antibody-Dependent Dengue Virus Entry Modulates Cell Intrinsic Responses for Enhanced Infection

Dengue is caused by infection with any one of four dengue viruses (DENV); the risk of severe disease appears to be enhanced by the cross-reactive or subneutralizing levels of antibody from a prior DENV infection. These antibodies opsonize DENV entry through the activating Fc gamma receptors (FcγR), instead of infection through canonical receptor-mediated endocytosis, to result in higher levels of DENV replication. However, whether the enhanced replication is solely due to more efficient FcγR-mediated DENV entry or is also through FcγR-mediated alteration of the host transcriptome response to favor DENV infection remains unclear. Indeed, more efficient viral entry through activation of the FcγR can result in an increased viral antigenic load within target cells and confound direct comparisons of the host transcriptome response under antibody-dependent and antibody-independent conditions. Herein, we show that, despite controlling for the viral antigenic load in primary monocytes, the antibody-dependent and non-antibody-dependent routes of DENV entry induce transcriptome responses that are remarkably different. Notably, antibody-dependent DENV entry upregulated DENV host dependency factors associated with RNA splicing, mitochondrial respiratory chain complexes, and vesicle trafficking. Additionally, supporting findings from other studies, antibody-dependent DENV entry impeded the downregulation of ribosomal genes caused by canonical receptor-mediated endocytosis to increase viral translation. Collectively, our findings support the notion that antibody-dependent DENV entry alters host responses that support the viral life cycle and that host responses to DENV need to be defined in the context of its entry pathway.IMPORTANCE Dengue virus is the most prevalent mosquito-borne viral infection globally, resulting in variable manifestations ranging from asymptomatic viremia to life-threatening shock and multiorgan failure. Previous studies have indicated that the risk of severe dengue in humans can be increased by a specific range of preexisting anti-dengue virus antibody titers, a phenomenon termed antibody-dependent enhancement. There is hence a need to understand how antibodies augment dengue virus infection compared to the alternative canonical receptor-mediated viral entry route. Herein, we show that, besides facilitating viral uptake, antibody-mediated entry increases the expression of early host dependency factors to promote viral infection; these factors include RNA splicing, mitochondrial respiratory chain complexes, vesicle trafficking, and ribosomal genes. These findings will enhance our understanding of how differences in entry pathways can affect host responses and offer opportunities to design therapeutics that can specifically inhibit antibody-dependent enhancement of dengue virus infection.

The association between family members' migration and Epstein-Barr virus antibody titers among people left behind in rural Fujian, China.

In contrast to the health of migrants, which has been extensively studied, little attention has been paid to the health of adults left behind by family members who out-migrated to other locations. This study was performed to investigate the association between being left behind and the Epstein-Barr virus (EBV) antibody titer, which is an indicator of cellular immune functioning previously shown to be associated with psychological stress. A cross-sectional survey was conducted in rural communities in Fujian, China, in 2015. Questionnaire data and dried blood spot samples were collected from 748 adults. A mixed effect regression analysis was conducted to investigate the association. Results indicated that the EBV antibody titers were higher among people who had been left behind compared with those who had not. Our findings suggest that, in rural Fujian, China, family separation following the out-migration of family members is an important determinant of psychological stress.

Sex differences in executive functioning and latent herpesvirus reactivation among bereaved and nonbereaved individuals.

The death of a spouse is a highly stressful event. Better executive functioning has been shown to benefit men to a greater degree than women during stress. We evaluated potential sex differences in stress and immune dysregulation among control and bereaved participants who completed a self-report measure of perceived stress, neuropsychological measures of inhibition and updating/monitoring of information in working memory, and a blood draw to measure Epstein-Barr virus (EBV) antibody titres. Moderation analyses were conducted to test the hypothesis that better inhibition would be associated with less stress and immune dysregulation among male bereaved participants compared with female bereaved participants. Bereaved females demonstrated greater EBV antibody titres than bereaved males. Male bereaved participants benefited from better inhibition, as evidenced by fewer EBV antibody titres, whereas bereaved female participants did not. In the control group, males with high inhibition reported lower stress than males with low inhibition. Present study results are an important step towards identifying those at greatest risk of stress and poor health.

High similarity of IgG antibody profiles in blood and saliva opens opportunities for saliva based serology.

Saliva based diagnostics is a rapidly evolving field due to the large diagnostic potential and simple sample collection. Currently only few individual molecules were investigated for their diagnostic capabilities in saliva. A systematic comparison of IgG antibody profiles in saliva and plasma is still missing in scientific literature. Our hypothesis is that IgG profiles in plasma and saliva are highly similar for each individual. As a consequence, one could implement practically any plasma based IgG assay (classical serology) as saliva based assay. In other words, the IgG antibodies found in blood are also accessible from saliva. We confirm our hypothesis by comparing IgG reactivities towards protein and peptide antigens. We isolated saliva IgG with high purity and demonstrate that plasma IgG reactivities (classical serology) can be inferred from saliva. As a showcase we perform Hepatitis B virus antibody (plasma-)titer determination from saliva. Additionally we show that plasma and saliva IgG profiles of 20 individuals are highly similar for 256 peptide antigens and match (unsupervised) with high probabilities. Finally, we argue for generalisation to the complete IgG antibody profile. The presented findings could contribute greatly to the development of saliva based diagnostic methods of numerous antibody based tests.

Association between early parental deprivation and cellular immune function among adults in rural Fujian, China.

This study investigated the role of childhood parental deprivation in the association between quality of life (QOL) and the Epstein-Barr virus (EBV) antibody titer, a marker of cellular immune functioning, using data from 734 adults living in seven communities in rural Fujian, China. Parental deprivation was defined if either of their parents had died, divorced, or left them for migratory work for more than 1year before they turned (a) 16years of age (childhood and adolescence), or (b) 3years of age (early childhood). A mixed-effects regression analysis with a random effects model revealed that parental deprivation during early childhood was positively associated with the EBV antibody titer (coefficient=0.33, p=0.007), whereas parental deprivation during the first 16years was not. Further analysis incorporating an interaction term between QOL and parental deprivation revealed a significant interaction between QOL and parental deprivation during early childhood; a significant association between QOL and the EBV antibody titer was found only among those who reported parental deprivation during early childhood. This study suggests that parental deprivation during the period of immune system development may be linked with physiological responses to stressors later in life.

Antibodies Against Egg- and Cell-Grown Influenza A(H3N2) Viruses in Adults Hospitalized During the 2017-2018 Influenza Season.

Influenza vaccine effectiveness was low in 2017-2018, yet circulating influenza A(H3N2) viruses were antigenically similar to cell-grown vaccine strains. Notably, most influenza vaccines are egg propagated. Serum specimens were collected shortly after illness onset from 15 influenza A(H3N2) virus-infected cases and 15 uninfected hospitalized adults. Geometric mean titers against egg- and cell-grown influenza A/Hong Kong/4801/2014(H3N2) virus vaccine strains and representative circulating viruses (including A/Washington/16/2017) were determined by a microneutralization (MN) assay. Independent effects of strain-specific titers on susceptibility were estimated by logistic regression. MN titers against egg-grown influenza A/Hong Kong virus were significantly higher among vaccinated individuals (173 vs 41; P = 0.01). In unadjusted models, a 2-fold increase in titers against egg-grown influenza A/Hong Kong virus was not significantly protective (29% reduction; P = .09), but a similar increase in the cell-grown influenza A/Washington virus antibody titer (3C.2a2) was protective (60% reduction; P = .02). Higher egg-grown influenza A/Hong Kong virus titers were not significantly associated with infection, when adjusted for antibody titers against influenza A/Washington virus (15% reduction; P = .61). A 54% reduction in the odds of infection was observed with a 2-fold increase in titer against influenza A/Washington virus (P = not significant), adjusted for the titer against egg-grown influenza A/Hong Kong virus titer. Individuals vaccinated in 2017-2018 had high antibody titers against the egg-adapted vaccine strain and lower titers against circulating viruses. Titers against circulating but not egg-adapted strains were correlated with protection.

Effect of plant extracts derived from thyme and chamomile on the growth performance, gut morphology and immune system of broilers fed aflatoxin B1 and ochratoxin A contaminated diets

This study was conducted to evaluate the ability of chamomile flower extract (CFE) and thyme-oil extract (TOE) for the preventing effect of ochratoxin A (OTA) and aflatoxin B1 (AFB) in broiler productivity, biochemical parameters, gut morphology and immune response of broilers. The experiment was conducted as a 3 × 4 factorial arrangement, being the factors: phytogenic additives (control, 3 g/kg diet of CFE, or 3 g/kg diet of TOE) and dietary contaminated diets (none, 0.50 mg/kg diet of AFB, 0.25 mg/kg diet of OTA, or 0.50 mg/kg diet of AFB + 0.25 mg/kg diet of OTA). Each of the 12 dietary treatments was fed to six replicate pens (10 birds/pen) from 0 to 28 d of age. Inclusion of phytogenic additives increased average daily gain (ADG) and average daily feed intake (ADFI), and decreased feed conversion ratio (FCR) from day 11 to 28 and day 0 to 28 in the birds fed OTA-AFB toxin diets. Significantly increased levels of HDL, IgG, IgM and anti-Newcastle disease virus (NDV) antibody titre were observed in the two essential oil-treated groups when compared with the control group. When compared with the control, relative weights of gizzard, liver and pancreas were significantly higher for broilers fed diets containing OTA alone. The results indicated that OTA and AFB toxins, alone or in combination, reduced villous height (VH) and ratio of VH to crypt depth in the jejunum. The levels of triglycerides, total cholesterol, HDL and plasma immunoglobulin, as well as NDV antibody titre were significantly decreased by AFB-OTA toxin combination. In summary, the combination of OTA and AFB impaired chick immune function even at combined concentrations as low as 0.25 mg/kg diet of OTA and 0.50 mg/kg diet of AFB. The inclusion of TOE and CFE can be an alternative to ameliorate the adverse effects of low doses of AFB and OTA in broiler diets.HighlightsOchratoxin A and aflatoxin B1, alone or in combination, affect negatively productive performance and immune function.Dietary inclusion of chamomile flower extract (CFE) and thyme-oil extract (TOE) had positive effects on growth performance and immune response.Addition of CFE and TOE to diets can ameliorate the adverse effects of mycotoxins in broiler diets.

Finding Jobs, Forming Families, and Stressing Out? Work, Family, and Stress among Young Adult Women in the United States.

AbstractThe transition to adulthood is increasingly characterized by complex paths into the world of work and family, especially for young women. Yet how work and family combine to influence stress among young adult women is not well understood. Using data from the National Longitudinal Study of Adolescent to Adult Health, we leverage new extensions to latent class analysis (LCA) to identify common combinations of work and family circumstances among young adult women, their earlier life and contemporaneous correlates, and associations with two stress measures: a multi-item Perceived Stress Scale (PSS) and Epstein–Barr Viral (EBV) antibody titers, a well-validated biomarker of stress-related immunity impairments. We identify seven different common combinations of latent work–family combinations among young adult women ranging from well-compensated professional workers with and without children, mothers without paid employment, and delayed transitions to work and family. Completing a college degree was associated with a higher likelihood of membership in classes marked by professional work irrespective of motherhood, while being raised in a community with greater female labor opportunities was generally associated with membership in child-free classes. Mothers and child-free women in “pink-collar” work with low wages and decision-marking freedom reported higher stress compared to women in “white-collar” work with higher wages and decision-making freedom. These differences are mostly attenuated following adjustments for poverty-related stressors and work–family conflict. While prior work has emphasized the health benefits for women of combining work and family, our research suggests these benefits may be limited to women of higher socioeconomic status with flexible, well-compensated jobs.

Immunoglobulins and virus antibody titers: of past needs, current requirements, and future options.

Immunoglobulins (Igs) have been in clinical use for almost 70 years, and early on were also used in conjunction with exposure to the measles virus or polio virus. The US regulations that describe functional Ig lot release thus require the demonstration of minimum antibody titers against these two viruses, although the use of vaccines has now dramatically reduced their incidence. The lower clinical importance of these viruses raises the question of whether other virus antibodies might be more informative for patients with immunodeficiency. A literature survey was conducted to identify viruses of potential clinical concern for people with immunodeficiency. The viruses selected have stable seroepidemiology and associated functional antibody assays. As a result, neutralizing antibody titers to human adenovirus 5 (HAdV5), respiratory syncytial virus (RSV) serotypes A and B, and human parainfluenza virus 3 (hPIV3) were determined in Ig lots produced from plasma collected in either the United States or the European Union. The virus antibody titers measured were high and consistent among the Ig lots tested. Use of either US- or EU-derived plasma as starting material resulted in equivalent virus antibody titers, with the exception of RSV serotype B, for which a lower titer was seen in EU plasma-derived Ig lots. With the significant decline in measles virus and polio virus circulation, and even their potential eradication, measurement of antibody titers against other viruses in Ig products may be more informative for functional lot release testing.

Recombinant Infectious Bronchitis Viruses Expressing Chimeric Spike Glycoproteins Induce Partial Protective Immunity against Homologous Challenge despite Limited Replication In Vivo.

Vaccination regimes against Infectious bronchitis virus (IBV), which are based on a single virus serotype, often induce insufficient levels of cross-protection against serotypes and two or more antigenically diverse vaccines are used in attempt to provide broader protection. Amino acid differences in the surface protein, spike (S), in particular the S1 subunit, are associated with poor cross-protection. Here, homologous vaccination trials with recombinant IBVs (rIBVs), based on the apathogenic strain, BeauR, were conducted to elucidate the role of S1 in protection. A single vaccination of specific-pathogen-free chickens with rIBV expressing S1 of virulent strains M41 or QX, BeauR-M41(S1) and BeauR-QX(S1), gave incomplete protection against homologous challenge, based on ciliary activity and clinical signs. There could be conformational issues with the spike if heterologous S1 and S2 are linked, suggesting a homologous S2 might be essential. To address this, a homologous vaccination-challenge trial incorporating rIBVs expressing full spike from M41, BeauR-M41(S), and S2 subunit from M41, BeauR-M41(S2) was conducted. All chimeric viruses grew to similar titers in vitro, induced virus-specific partial protective immunity, evident by cellular infiltrations, reductions in viral RNA load in the trachea and conjunctiva and higher serum anti-IBV titers. Collectively, these findings show that vaccination with rIBVs primed the birds for challenge but the viruses were cleared rapidly from the mucosal tissues in the head. Chimeric S1 and S2 viruses did not protect as effectively as BeauR-M41(S) based on ciliary activity and clinical signs. Booster vaccinations and an rIBV with improved in vivo replication may improve the levels of protection.IMPORTANCE Infectious bronchitis virus causes an acute, highly contagious respiratory disease, responsible for significant economic losses to the poultry industry. Amino acid differences in the surface protein, spike (S), in particular the S1 subunit, have been associated with poor cross-protection. Available vaccines give poor cross-protection and rationally designed live attenuated vaccines, based on apathogenic BeauR, could address these. Here, to determine the role of S1 in protection, a series of homologous vaccination trials with rIBVs were conducted. Single vaccinations with chimeric rIBVs induced virus-specific partial protective immunity, characterized by reduction in viral load and serum antibody titers. However, BeauR-M41(S) was the only vaccination to improve the level of protection against clinical signs and the loss of tracheal ciliary activity. Growth characteristics show that all of the rIBVs replicated in vitro to similar levels. Booster vaccinations and an rIBV with improved in vivo replication may improve the levels of protection.

Effects of dietary yeast nucleotides supplementation on intestinal barrier function, intestinal microbiota, and humoral immunity in specific pathogen-free chickens.

Yeast nucleotides are a fine functional additive in human and animals. The effects of dietary yeast nucleotides supplementation on intestinal development, expression of intestinal barrier-related genes, intestinal microbiota, and infectious bronchitis virus (IBV) antibody titer of specific pathogen-free (SPF) chickens were investigated. A total of 60 1-d-old chickens were divided into 4 groups, each of which included 3 replicates of 5 chickens. Group 1 served as a control that was fed a basal diet. Groups 2 to 4 were fed the basal diet supplemented with 0.1%, 0.3% and 0.5% yeast nucleotides, respectively. All chickens were inoculated intranasally with inactivated IBV vaccine at day 1 and day 10. At day 17, the intestinal development, expression of intestinal barrier-related genes and microbiota were evaluated. There was a significant increased ileal villus height and villus height to crypt depth ratio in group 2 (P < 0.05). Moreover, group 4 exhibited higher expression of zonula occludens-1 (ZO-1) and Occludin gene in ileum (P < 0.05), whereas groups 2 and 3 exhibited higher expression of Mucin 2 (MUC2) and trefoil factor 2 (TFF2) gene (P < 0.05), group 2 showed lower expression of IFN-α gene (P < 0.05). Dietary yeast nucleotides increased intestinal bacterial diversity (P < 0.05), and the abundance of Lactobacillus (P < 0.05). At day 10, 17, 24, 31, 38, and 45, the serum IBV antibody titers were tested. Group 2 exhibited higher IBV antibody titer at day 17 (P < 0.05), furthermore, groups 2 to 4 reached the effective levels 1 wk earlier than control group. In conclusion, dietary yeast nucleotides supplementation can help birds to mount a faster and stronger antibody response to IBV vaccine. In addition, dietary yeast nucleotides supplementation can also promote the intestinal development and barrier-related genes expression, and diversity and richness of intestinal microbiota.

Long-term monitoring of virus antibody titers in human intravenous immunoglobulin lots derived from donors in Japan.

Intravenous immunoglobulin (IVIG) contains immunoglobulin G against various viruses, except those that have been screened, such as human immunodeficiency and hepatitis C viruses. Antivirus titers reflect the serostatus of the blood donor population in the collection region and are of clinical interest. During the past 10 years, measles, mumps, rubella, varicella-zoster, hepatitis A and B, Epstein-Barr, and human respiratory syncytial viruses; human parainfluenza viruses 1, 2, and 3; human herpes simplex viruses 1 and 2; human herpesvirus 6; cytomegalovirus (CMV); human adenoviruses (HAdVs) 1, 2, 3, 7, and 11; human parvovirus B19; and human echovirus 9 and 11 titers in IVIG lots have been measured by a commercial testing facility. A viral neutralizing assay for CMV has been used at our facility. Herein, we summarize the measurements and results of a regression analysis of the trends in virus antibody titers. IVIG lots contained significant titers against all of the above viruses, except for HAdV 7. Three patterns-stable, increasing, and decreasing-were observed, without any drastic changes. Although these trends reflect the seroprevalence in Japan, the titers were not obviously affected by the cycle of epidemics. On the other hand, the prevalence data suggest that titers against hepatitis A virus and other viruses will decrease in the near future, although they are currently stable. Monitoring the titer of IVIG lots and seroprevalence of donor populations is important for anticipating future changes in virus antibody titers of IVIG lots and can provide useful information of clinical interest.

Efficacy of Ontario Rabies Vaccine Baits (ONRAB) against rabies infection in raccoons

In the US, rabies lyssavirus (RABV) only circulates in wildlife species and the most significant reservoir from a public and animal health perspective is the raccoon (Procyon lotor). Management of wildlife rabies relies principally on oral rabies vaccination (ORV) strategies using vaccine-laden bait delivery to free-ranging target hosts, in order to reduce the susceptible population to prevent the spread of and eliminate RABV circulation. Our objective was to evaluate efficacy of the Ontario Rabies Vaccine Bait (ONRAB) against a lethal RABV challenge in captive raccoons. Sham or live vaccine baits were offered to 50 raccoons and efficacy was evaluated in 46, split into two trials of 17 and 29 raccoons. Raccoons were challenged with a lethal dose of RABV 180 days post-vaccination and observed for 90 days post-infection. Raccoon bait interactions were assigned increasing integer scores for approach, oral manipulation, puncture, and consumption behaviors. Higher bait interaction scores were observed in the fall compared to the spring trial, indicating that more raccoons consumed baits in the fall. Although animal age did not explain variation in bait interaction scores, the geometric mean rabies virus antibody titers among juvenile vaccinates were higher than adults at all pre-challenge time points. The prevented fraction associated with ONRAB delivery was 0.73 (8/11, 95% CI 0.39–0.94) in the spring trial and 0.91 (21/23, 95% CI 0.72–0.99) in the fall trial. All sham-vaccinated raccoons (12/12) succumbed to rabies infection, in contrast to 15% (5/34) mortality among vaccinated raccoons. Our results indicate a high efficacy of ONRAB bait vaccination in protecting adult and juvenile raccoons against RABV infection for a minimum of six months. These data complement experimental field trials that have also demonstrated the potential of ONRAB for the control and prevention of RABV circulation in free-ranging raccoon populations in the US.

Epstein-Barr Virus Antibody Titers Are Not Associated with Gastric Cancer Risk in East Asia.

Epstein-Barr virus (EBV)-positive gastric cancers represent a distinct subtype of gastric cancers and account for nearly 10% of the gastric cancer burden, yet risk detection strategies for this cancer subtype are lacking. We conducted a nested case-control study where we assayed 4 EBV antigens [viral capsid antigen (VCA), early antigen (EA), Epstein-Barr nuclear antigen (EBNA), and BZLF1-encoded replication activator protein (ZEBRA)] in either sera or plasma from 1447 gastric cancer cases and 1797 controls obtained from seven prospective cohorts representing individuals from the high gastric cancer-risk countries of China, Japan, and Korea. The prevalence of EBV sero-positivity was universal with the exception of one sero-negative individual, and the highest titers of the EBV antigens VCA (OR 0.95, 95% CI 0.78-1.17), EBNA (OR 0.88, 95% CI 0.72-1.08), EA (OR 0.97, 95% CI 0.79-1.19), and ZEBRA (OR 0.87, 95% CI 0.71-1.07) were not associated with risk of incident gastric cancer. When we stratified these data by H. pylori status, there was no change in the association. Multiplex serology of the aforementioned EBV antigens in serum may not be a suitable biomarker for predicting gastric cancer risk in East Asian populations.

Epstein-Barr virus antibody titer as a stress biomarker and its association with social capital in rural Fujian communities, China.

There has been little research on the association between social capital and psychological stress measured by a biomarker, particularly in developing countries. Our objective was to investigate the association between Epstein-Barr virus (EBV) antibody titer, an indicator of cellular immune function previously shown to be associated with psychological stress, and social capital among rural community dwellers in Fujian Province, China. We conducted a cross-sectional survey in seven rural communities in Fujian in 2015. We used questionnaire data and dried blood spot samples for the measurement of biomarkers collected from 734 local residents for the analysis. We conducted a mixed effects regression analysis to investigate the association between EBV antibody titer and four social capital variables, which included cognitive and structural social capital assessed both at individual and community levels. Community-level structural social capital was inversely associated with psychological stress (coefficient = -0.96, 95% confidence interval [CI] = -1.91, -0.01) while individual-level structural social capital was positively associated with it (coefficient = 0.21, 95% CI = 0.07, 0.36). Neither individual- nor community-level cognitive social capital was associated with psychological stress status. In rural Fujian, China, social capital seemed to be an important determinant of psychological health. While living in a community with active social interaction may benefit the residents psychologically, social interaction in the form of strongly bonded relationships may be a source of psychological stress at the individual level due to the potential demands and obligations that may be associated with such connections.

A novel sampling method to detect airborne influenza and other respiratory viruses in mechanically ventilated patients: a feasibility study

BackgroundRespiratory viruses circulate constantly in the ambient air. The risk of opportunistic infection from these viruses can be increased in mechanically ventilated patients. The present study evaluates the feasibility of detecting airborne respiratory viruses in mechanically ventilated patients using a novel sample collection method involving ventilator filters.MethodsWe collected inspiratory and expiratory filters from the ventilator circuits of mechanically ventilated patients in an intensive care unit over a 14-month period. To evaluate whether we could detect respiratory viruses collected in these filters, we performed a reverse transcription polymerase chain reaction on the extracted filter membrane with primers specific for rhinovirus, respiratory syncytial virus, influenza virus A and B, parainfluenza virus (type 1, 2 and 3) and human metapneumovirus. For each patient, we also performed a full virology screen (virus particles, antibody titres and virus-induced biomarkers) on respiratory samples (nasopharyngeal swab, tracheal aspirate or bronchoalveolar fluid) and blood samples.ResultsRespiratory viruses were detected in the ventilator filters of nearly half the patients in the study cohort (n = 33/70). The most common virus detected was influenza A virus (n = 29). There were more viruses detected in the inspiratory filters (n = 18) than in the expiratory filters (n = 15). A third of the patients with a positive virus detection in the ventilator filters had a hospital laboratory confirmed viral infection. In the remaining cases, the detected viruses were different from viruses already identified in the same patient, suggesting that these additional viruses come from the ambient air or from cross-contamination (staff or visitors). In patients in whom new viruses were detected in the ventilator filters, there was no evidence of clinical signs of an active viral infection. Additionally, the levels of virus-induced biomarker in these patients were not statistically different from those of non-infected patients (p = 0.33).ConclusionsRespiratory viruses were present within the ventilator circuits of patients receiving mechanical ventilation. Although no adverse clinical effect was evident in these patients, further studies are warranted, given the small sample size of the study and the recognition that ventilated patients are potentially susceptible to opportunistic infection from airborne respiratory viruses.

HLA alleles modulate EBV viral load in multiple sclerosis

BackgroundThe etiopathology of multiple sclerosis (MS) is believed to include genetic and environmental factors. Human leukocyte antigen (HLA) alleles, in particular, are associated with disease susceptibility, whereas Epstein Barr Virus (EBV) infection has long been suspected to play a role in disease pathogenesis. The aim of the present study is to evaluate correlations between HLA alleles and EBV infection in MS.MethodsHLA alleles, EBV viral load (VL) and serum anti-EBV antibody titers were evaluated in EBV-seropositive MS patients (N = 117) and age- and sex-matched healthy controls (HC; N = 89).ResultsSignificantly higher DNA viral loads (p = 0.048) and EBNA-1 antibody titer (p = 0.0004) were seen in MS compared to HC. EBV VL was higher in HLA-B*07+ (p = 0.02) and HLA-DRB1*15+ (p = 0.02) MS patients, whereas it was lower in HLA-A*02+ (p = 0.04) subjects. EBV VL was highest in HLA-A*02−/B*07+/DRB1*15+ patients and lowest in HLA-A*A02+/B*07−/DRB1*15− individuals (p < 0.0001). HLA-B*07 resulted the most associated allele to EBV VL after multiple regression analysis considering altogether the three alleles, (p = 0.0001). No differences were observed in anti-EBV antibody titers in relationship with HLA distribution.ConclusionsHost HLA-B*07 allele influence EBV VL in MS. As HLA-class I molecules present antigens to T lymphocytes and initiate immune response against viruses, these results could support a role for EBV in MS.

Viral load and antibody boosting following herpes zoster diagnosis

BackgroundAcute varicella zoster virus (VZV) replication in shingles is accompanied by VZV antibody boosting. It is unclear whether persisting virus shedding affects antibody levels. ObjectivesTo investigate the relationship between VZV viral load and antibody titres in shingles patients during six months following diagnosis and assess whether VZV antibody titre could discriminate patients with recent shingles from healthy population controls. Study designA prospective study of 63 patients with active zoster. Blood samples were collected at baseline, one, three and six months to measure VZV DNA and IgG antibody titre. We compared VZV antibody titres of zoster patients and 441 controls. ResultsIn acute zoster, viral load was highest at baseline and declined gradually over the following six months. Mean antibody titres rose fourfold, peaking at one month and remaining above baseline levels throughout the study. Antibody levels at one, three and six months after zoster were moderately correlated with baseline but not subsequent viral load. Regarding use of antibody titres to identify recent shingles, to achieve 80% sensitivity, specificity would be 23.4%, 67.7%, 64.8% and 52.6%, at baseline, visit 2, 3 and 4 respectively, whilst to achieve 80% specificity, sensitivity would be 28.3%, 66.1%, 52.6%, 38.6%, at baseline, visit 2, 3 and 4 respectively. ConclusionsClinical VZV reactivation boosted VZV antibody levels and the level of boosting was dependent upon baseline viral replication. While antibody titres could discriminate patients with shingles 1–6 months earlier from blood donor controls, there was a large trade-off between sensitivity and specificity.

Delayed facial nerve palsy after vestibular schwannoma surgery

Background: Facial nerve dysfunction may occur immediately after vestibular schwanoma surgery. Electromyographyc monitoring of motor cranial nerves during cerebellopontine angle surgery has become an essential tool. Although delayed onset of facial nerve dysfunction hours to months following vestibular schwanoma surgery are rare. Case description: We describe the case of a 70-years-old male who was admitted with a left side tinnitus and hearing loss of the last 3 years. Magnetic resonance imaging (MRI) T1-weighted demonstrated an isointensity lesion, 30mm in diameter, at the left cerebello-pontine angle with a small portion in the internal auditory canal. The patient was surgically treated by means of a standart suboccipital retrosigmoid approach. The facial nerve was monitored by continuously during surgery. Surgical removal was macroscopically complete. The facial nerve was well-preserved during surgery and showed at the end of the procedure normal electromyographic activity. The patient did well postoperatively and was discharged at the 4th postoperative day and facial function was normal (House-Brackmann grade I). On the 10th postoperative day he notices difficult closing his left eye that progressed to complete facial nerve palsy (House-Brackmann grade III). Steroid therapy was performed for five days associated with physical therapy. One month later his facial nerve function had completely recovered. After six months, the patient remains asymptomatic and neurologically intact. MRI obtained at the 16th postoperative day showed intense enhancement of the intracranial facial nerve segment and also demonstrated no residual tumor. Immunological study at the time of onset showed herpes simplex virus antibody titer normal as well as those for herpes zoster virus. Conclusions: Delayed facial nerve palsy remains an under reported and consequently not very known phenomenon in the neurosurgical practice and literature. Because of the 2009favorable rate of recovery, patients should be reassured in the interim and should not undergo any corrective surgical procedures to improve facial nerve function. Delayed facial nerve palsy is uncommon after vestibular schwannoma surgery. Excellent recovery of facial nerve function to the original postoperative status nearly always occurs in those circumstances.

Molecular analysis of carnivore Protoparvovirus detected in white blood cells of naturally infected cats

BackgroundCats are susceptible to feline panleukopenia virus (FPV) and canine parvovirus (CPV) variants 2a, 2b and 2c. Detection of FPV and CPV variants in apparently healthy cats and their persistence in white blood cells (WBC) and other tissues when neutralising antibodies are simultaneously present, suggest that parvovirus may persist long-term in the tissues of cats post-infection without causing clinical signs. The aim of this study was to screen a population of 54 cats from Sardinia (Italy) for the presence of both FPV and CPV DNA within buffy coat samples using polymerase chain reaction (PCR). The DNA viral load, genetic diversity, phylogeny and antibody titres against parvoviruses were investigated in the positive cats.ResultsCarnivore protoparvovirus 1 DNA was detected in nine cats (16.7%). Viral DNA was reassembled to FPV in four cats and to CPV (CPV-2b and 2c) in four cats; one subject showed an unusually high genetic complexity with mixed infection involving FPV and CPV-2c. Antibodies against parvovirus were detected in all subjects which tested positive to DNA parvoviruses.ConclusionsThe identification of FPV and CPV DNA in the WBC of asymptomatic cats, despite the presence of specific antibodies against parvoviruses, and the high genetic heterogeneity detected in one sample, confirmed the relevant epidemiological role of cats in parvovirus infection.