Cytomegalovirus infection and development of allergic diseases in early childhood: interaction with EBV infection?

Association of IgE elevation with blood group in COVID-19 patients

Aim : All parameters that are thought to be efficient in getting sick and follow-up of the disease should be investigated because of COVID-19 disease has serious consequences. The aim of this study was to investigate whether there is a relationship between the AB0 blood group with Rh factor systems and the frequency of catching COVID-19 infection and between IgE elevation according to blood groups and COVID-19 positivity. Material and Method: Blood groups and IgE levels of the control group (2690 patients) were compared retrospectively with 7300 patients who were admitted to our hospital between March 10, 2020, and March 31, 2021, and confirmed as COVID-19 positive with viral ribonucleic acid reverse transcriptase-polymerase chain reaction (RT-PCR). Results: It was found that among the blood groups, the highest COVID-19 positivity belonged to the A blood group (46.17%) and the lowest belonged to the AB blood group (9.04%). The increase in IgE elevation was found statistically significant in COVID-19 positive patients (P

Early-life infections in association with development of atopic dermatitis in infancy and early childhood: A nationwide nested case-control study

BACKGROUND

Microbial dysbiosis has been implicated in the development of atopic dermatitis (AD). The risk of development of AD following early-life infections remains unclear.

OBJECTIVE

To investigate the impact of early-life infections on AD development.

METHODS

This population-based nested case-control study was conducted using the Taiwan's National Health Insurance Research Database. A total of 5,454 AD patients and 16,362 control subjects without AD were identified, for the period 1997 to 2013. Demographic characteristics, comorbidities, and maternal factors were compared. Adjusted odds ratio (aOR) was calculated to examine the associations between early-life infections and subsequent AD by conditional stepwise logistic regression analysis.

RESULTS

Mean age was 2.6±2.9 years in both groups. Overall infections (41.8% vs 28.9%) before the diagnosis of AD were more common in AD patients than in control subjects (p<.001). Infectious diseases (aOR, 1.40; 95% confidence interval [CI], 1.29-1.51), skin infections (aOR, 1.55; 95% CI, 1.40-1.71) and systemic antibiotic exposure (aOR 1.67, 95% CI 1.55-1.79) before AD diagnosis were independently associated with AD development on multivariate analyses. These results were consistent across observation periods (0-1, 1-2, and >2 years after birth) and sensitivity analyses after redefining the index date as 3 or 6 months before the date of AD diagnosis. Other independent risk factors included asthma, allergic rhinitis, intussusception, and neonatal hyperbilirubinemia. No association with subsequent AD was found for maternal age at delivery, Cesarean delivery, or prenatal antibiotic exposure.

CONCLUSION

Infections in early life are associated with AD development in infancy and early childhood.

Risk of herpesvirus, serious, and opportunistic infections in atopic dermatitis: a population-based cohort study

BACKGROUND

Staphylococcal and herpes simplex virus (HSV) infections are commonly recognized in atopic dermatitis (AD) but less is known about other types of infections.

OBJECTIVES

To determine the risk of herpesvirus infections, serious infections, and opportunistic infections in patients with AD.

METHODS

We conducted a population-based cohort study using UK-based electronic medical records data. Patients with AD were each matched to up to 5 unaffected patients on age, practice, and index date. AD severity was defined using treatments. The outcomes were incident herpesvirus infections (cytomegalovirus [CMV], Epstein-Barr virus [EBV], HSV, or varicella zoster virus [VZV]), serious infections, and opportunistic infections.

RESULTS

409,431 children and 625,083 adults with AD were matched to 1,809,029 children and 2,678,888 adults without AD, respectively. In adjusted Cox regression models, children and adults with AD had 50-52% greater risk of HSV and 18-33% greater risk of VZV, with risk increasing in parallel with AD severity. CMV risk was elevated among children with AD (HR 2.50 [1.38-4.54]) and adults with severe AD (4.45 [1.76-11.25]). Patients with AD had 26-40% increase in risk of serious infections, with severe AD carrying greatest risk. Although rare, opportunistic infections were not associated with AD in children but were associated with all severities of AD in adults (overall HR 1.31 [1.20-1.42]). All estimates remained consistent after excluding patients receiving immunosuppressive treatments for AD.

CONCLUSIONS

AD is significantly associated with herpesvirus infections, serious infections, and opportunistic infections in a dose-responsive manner with severity. AD may increase susceptibility to infections exclusive of immunosuppressive medications.

Common Childhood Viruses and Pubertal Timing: The LEGACY Girls Study

Earlier pubertal development is only partially explained by childhood body mass index; the role of other factors, such as childhood infections, is less understood. Using data from the LEGACY Girls Study (North America, 2011-2016), we prospectively examined the associations between childhood viral infections (cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus (HSV) 1, HSV2) and pubertal timing. We measured exposures based on seropositivity in premenarcheal girls (n = 490). Breast and pubic hair development were classified based on mother-reported Tanner Stage (TS) (TS2+ compared with TS1), adjusting for age, body mass index, and sociodemographic factors. The average age at first blood draw was 9.8 years (standard deviation, 1.9 years). The prevalences were 31% CMV+, 37% EBV+, 14% HSV1+, 0.4% HSV2+, and 16% for both CMV+/EBV+ coinfection. CMV+ infection without coinfection was associated with developing breasts an average of 7 months earlier (hazard ratio (HR) = 2.12, 95% confidence interval (CI): 1.32, 3.40). CMV infection without coinfection and HSV1 and/or HSV2 infection were associated with developing pubic hair 9 months later (HR = 0.41, 95% CI: 0.24, 0.71, and HR = 0.42, 95% CI: 0.22, 0.81, respectively). Infection was not associated with menarche. If replicated in larger cohorts with blood collection prior to any breast development, this study supports the hypothesis that childhood infections might play a role in altering pubertal timing.

Reduced Ebola vaccine responses in CMV+ young adults is associated with expansion of CD57+KLRG1+ T cells

CMV is associated with immunosenescence and reduced vaccine responses in the elderly (>70 yr). However, the impact of CMV in young adults is less clear. In this study, healthy UK and Senegalese adults aged 18–50 yr (average, 29 yr) were vaccinated with the Ebola vaccine candidate chimpanzee adenovirus type 3–vectored Ebola Zaire vaccine (ChAd3-EBO-Z) and boosted with modified vaccinia Ankara Ebola Zaire–vectored (MVA–EBO-Z) vaccine. CMV carriage was associated with an expansion of phenotypically senescent CD4⁺ and CD8⁺ T cells expressing CD57 and killer cell lectin-like receptor G1 (KLRG1), which was negatively associated with vaccine responses in both cohorts. Ebola-specific T cell responses induced by vaccination also contained significantly increased frequencies of terminally differentiated CD57⁺KLRG1⁺ cells in CMV seropositive (CMV⁺) individuals. This study suggests that CMV can also affect vaccine responses in younger adults and may have a particularly marked impact in many developing countries where CMV seroprevalence is almost universal.

The influence of Epstein-Barr virus and cytomegalovirus on childhood respiratory health: A population-based prospective cohort study

Background

Epstein‐Barr virus (EBV) and cytomegalovirus (CMV) infection are common in early childhood. CMV infection favours a T‐helper‐1 and EBV infection a T‐helper‐2 cell response, possibly leading to disbalanced T‐helper cell response, and subsequent risk of asthma or atopy.

Objective

To study the associations of EBV and CMV with lung function, asthma and inhalant allergic sensitization at school age.

Methods

This study among 3546 children was embedded in a population‐based prospective cohort. At age 6 years, serum IgG levels against EBV and CMV were measured by ELISA. At age 10 years, lung function was measured by spirometry, asthma by questionnaire and inhalant allergic sensitization by skin prick test.

Results

Unadjusted models showed that seropositivity for EBV was associated with a higher FEV₁ and FEF₇₅ (Z‐score difference (95% CI): 0.09 (0.02, 0.16) and 0.09 (0.02, 0.15)), while seropositivity for CMV was not. Specific combinations of viruses showed that seropositivity for EBV was only associated with FEV₁ and FEF₇₅ in the presence of seropositivity for CMV (0.12 (0.04, 0.20)) and 0.08 (0.01, 0.15)). Seropositivity for CMV in the absence of seropositivity for EBV was associated with an increased risk of inhalant allergic sensitization (OR (95% CI): 1.31 (1.02, 1.68)). All effect estimates attenuated into non‐significant mainly after adjustment for child's ethnicity. Seropositivity for EBV or CMV was not associated with asthma.

Conclusions and Clinical Relevance

Associations of EBV and CMV infections in early childhood with school‐age lung function and inhalant allergic sensitization are explained by ethnicity, or sociodemographic and lifestyle‐related factors.

Age at cytomegalovirus, Epstein Barr virus and varicella zoster virus infection and risk of atopy: The Born in Bradford cohort, UK

BACKGROUND

The prevalence of allergic diseases has increased in recent decades, but the causes remain unclear. Changes in the epidemiology of childhood infections could have contributed, but the current evidence is inconclusive. This study aims to investigate whether age at cytomegalovirus (CMV), Epstein-Barr virus (EBV) or varicella zoster virus (VZV) infection is associated with the development of atopy.

METHODS

A total of 2559 children were enrolled in the Born in Bradford Allergy and Infection Study. Serum samples collected at 12 and 24 months were tested for CMV-IgG, EBV-IgG and VZV-IgG for 1000 children to establish age at infection. Skin prick testing (SPT) was conducted at age 4 years.

RESULTS

Serology and SPT results were available for 740 children. Of these, 135 (18%) were atopic. In girls, there was a strong association of CMV infection in the second year with increased odds of atopy (adjusted OR 4.38, 95% CI 1.87-10.29) but this was not observed in boys. Age at EBV or VZV infection was not associated with risk of atopy in unadjusted analysis, but there was effect modification by sex; girls infected with VZV in the second year of life had increased odds of atopy (adjusted OR 2.85, 95% CI 1.29-6.30).

CONCLUSIONS

Our results highlight potential sex-specific effects of age at CMV infection and age at VZV infection on risk of atopy, which provide insight into the mechanisms involved in the development of atopy.

Rhinoviruses in infancy and risk of immunoglobulin E sensitization

Previous data about the role of viruses in the development of allergic immunoglobulin E (IgE) sensitization are contradictory. The aim of this study was to determine the possible associations between exposure to different viruses (rhinovirus, enterovirus, norovirus, and parechovirus) during the first year of life and IgE sensitization. Viruses were analyzed from stool samples collected monthly from infants participating in a prospective birth cohort study. From that study, 244 IgE sensitized case children and 244 nonsensitized control children were identified based on their allergen-specific IgE antibody levels at the age of 6, 18, and 36 months. Stool samples (n = 4576) from the case and control children were screened for the presence of rhinovirus, enterovirus, norovirus, and parechovirus RNA by reverse transcription quantitative polymerase chain reaction. The study showed that rhinovirus was the most prevalent virus detected, present in 921 (20%) samples. None of the viruses were associated with IgE sensitization in the full cohort but after stratifying by sex, the number of rhinovirus positive samples was inversely associated with IgE sensitization in boys (odds ratio [OR]: 0.81; 95% confidence interval [CI]: 0.69-0.94; P = 0.006). There was also a temporal relation between rhinoviruses and IgE sensitization, as rhinovirus exposure during the first 6 months of life was associated with a reduced risk of subsequent IgE sensitization in boys (OR: 0.76; 95% CI: 0.6-0.94; P = 0.016). In conclusion, early exposure to rhinoviruses was inversely associated with IgE sensitization but this protective association was restricted to boys.

Cytomegalovirus DNA is highly prevalent in the blood of patients with asthma and is associated with age and asthma traits

Cytomegalovirus (CMV) IgG antibodies have been associated with inflammaging and immunosenescence. We aimed to assess the presence of CMV DNA in the blood of adult and elderly patients with bronchial asthma to establish potential association of CMV DNAemia with asthma and asthma characteristics. Eighty-five elderly asthmatics, 74 younger asthma patients, and 114 age-matched controls were recruited. The CMV DNA was detected using commercial artus assay in 10.7% of asthma patients, but was negative in all control individuals. The secondary assay identified CMV DNA in 41.5% of asthmatics and 13.3% of control subjects (P < .001). Presence of CMV DNA was associated with an increased risk of asthma and CMV DNA copy numbers correlated with some asthma traits, including respiratory parameters and exhaled breath nitric oxide. We conclude that CMV infection is associated with asthma and may contribute to the pathogenesis of asthmatic inflammation.

Risks for comorbidity in children with atopic disorders: an observational study in Dutch general practices

OBJECTIVE

This study aimed to investigate both atopic and non-atopic comorbid symptoms and diseases in children with physician-diagnosed atopic disorders (atopic eczema, asthma and allergic rhinitis).

METHODS

All children aged 0-18 years listed in a nationwide primary care database (the Netherlands Institute for Health Services Research-Primary Care Database) with routinely collected healthcare data in 2014 were selected. Children with atopic disorders were matched on age and gender with non-atopic controls within the same general practice. A total of 404 International Classification of Primary Care codes were examined. Logistic regression analyses were performed to examine the associations between the presence of atopic disorders and (non-)atopic symptoms and diseases by calculating ORs.

RESULTS

Having one of the atopic disorders significantly increased the risk of having other atopic-related symptoms, even if the child was not registered as having the related atopic disorder. Regarding non-atopic comorbidity, children with atopic eczema (n=15 530) were at significantly increased risk for (infectious) skin diseases (OR: 1.2-3.4). Airway symptoms or (infectious) diseases (OR: 2.1-10.3) were observed significantly more frequently in children with asthma (n=7887). Children with allergic rhinitis (n=6835) had a significantly distinctive risk of ear-nose-throat-related symptoms and diseases (OR: 1.5-3.9). Neither age nor gender explained these increased risks.

CONCLUSION

General practitioners are not always fully aware of relevant atopic and non-atopic comorbidity. In children known to have at least one atopic disorder, specific attention is required to avoid possible insufficient treatment and unnecessary loss of quality of life.

Cytomegalovirus, Epstein-Barr virus and varicella zoster virus infection in the first two years of life: a cohort study in Bradford, UK

Background

Cytomegalovirus (CMV), Epstein Barr virus (EBV) and varicella-zoster virus (VZV) are common herpesviruses frequently acquired in childhood, which establish persistent, latent infection and are likely to impact the developing immune system. Little is known about the epidemiology of CMV and EBV infections in contemporary UK paediatric populations, particularly whether age at infection differs by ethnic group.

Methods

Children enrolled in the Born in Bradford Allergy and Infection Study had a blood sample taken and a questionnaire completed at 12 and 24 months of age. Ordered logistic regression quantified associations between ethnicity and other risk factors and age at CMV/EBV/VZV infection (<12 months, 12–24 months, uninfected at 24 months).

Results

Pakistani children (n = 472) were more likely to be infected with CMV and EBV at a younger age than White British children (n = 391) (CMV: adjusted odds ratio (OR) 2.53, 95% confidence interval (CI) 1.47–4.33; EBV: adjusted OR 2.16, 95% CI 1.43–3.26). Conversely, Pakistani children had lower odds of being VZV infected in the second year than White British children (adjusted OR 0.57, 95% CI 0.33–0.97). There was a strong association between increasing birth order and later CMV infection in Pakistani children.

Conclusions

We report large differences in CMV and EBV incidence in the first 2 years between Pakistani and White British children born in Bradford, which cannot be explained by differences in risk factors for infection. Our data will inform the optimum schedule for future CMV and EBV vaccination programmes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2319-7) contains supplementary material, which is available to authorized users.

Determinants of Ethnic Differences in Cytomegalovirus, Epstein-Barr Virus, and Herpes Simplex Virus Type 1 Seroprevalence in Childhood

OBJECTIVE

To identify whether there are ethnic differences in cytomegalovirus (CMV), Epstein-Barr virus (EBV), and herpes simplex virus type 1 (HSV-1) seroprevalence rates in children at 6 years of age, and when present, to evaluate how these differences can be explained by sociodemographic and environmental factors.

STUDY DESIGN

This study was embedded within a multi-ethnic population-based prospective cohort study. Serum IgG levels against CMV, EBV, and HSV-1 were measured by enzyme-linked immunosorbent assay in 4464 children (median age 6.0 years). Information on demographics and characteristics were assessed by questionnaires. Herpesvirus seroprevalences between Surinamese-Creole, Surinamese-Hindustani, Turkish, Moroccan, Cape Verdean Antillean, and Native Dutch children were compared.

RESULTS

Non-Western ethnicity was an independent risk factor for CMV (aOR, 2.16; 95% CI 1.81-2.57), EBV (1.76; 1.48-2.09), and HSV-1 seropositivity (1.52; 1.39-1.66). Among the ethnic groups, CMV seroprevalences ranged between 29% and 65%, EBV between 43% and 69%, and HSV-1 between 13% and 39%. Low family net household income, low maternal educational level, crowding, and lifestyle factors explained up to 48% of the ethnic differences in HSV-1 seroprevalences, and up to 39% of the ethnic differences in EBV seroprevalences. These factors did not explain ethnic differences in CMV seroprevalences.

CONCLUSIONS

Socioeconomic position and factors related to lifestyle explain only a part of the large ethnic differences in EBV and HSV-1 seroprevalences, whereas they do not explain ethnic differences in CMV seroprevalences in childhood.

Associations between EBV and CMV Seropositivity, Early Exposures, and Gut Microbiota in a Prospective Birth Cohort: A 10-Year Follow-up

Early-life infections with persistent Epstein-Barr virus (EBV) and cytomegalovirus (CMV) are delayed in affluent countries, probably due to alterations in early environmental exposures, such as maternal age, siblings, and day-care attendance. We have previously reported that the timing of EBV and CMV contraction is related both to allergic sensitization and changes in functional competence of immune cells, while the presence/absence of lactobacilli [Lactobacillus (L.) casei, L. paracasei, and L. rhamnosus] or Staphylococcus (S.) aureus in feces is related to the risk for allergy. Here, we used the same prospective longitudinal birth cohort of children to investigate early-life environmental exposures and their influence on EBV and CMV contraction over time. Since gut microbes also belong to this category of early exposures, we investigated their association with herpesvirus contraction. Our results show that these two viruses are acquired with different kinetics and that EBV and CMV seroprevalence at 10 years of age was 47 and 57%, respectively. We also observed that a delayed EBV or CMV infection was associated with older maternal age [time ratio (TR) 1.14, 95% confidence interval (CI) 1.07-1.21, P adj < 0.001 and TR 1.09, CI 1.03-1.16, P adj = 0.008, respectively]. Further, we present the novel finding that S. aureus colonization reduced the time to CMV acquisition (TR 0.21, CI 0.06-0.78, P adj = 0.02). Together, these findings suggest that there is a relationship between timing of herpesvirus acquisition and early-life immune modulating exposures, which interestingly also includes the early infant gut microbiota.

Cytomegalovirus- and Epstein-Barr Virus-Induced T-Cell Expansions in Young Children Do Not Impair Naive T-cell Populations or Vaccination Responses: The Generation R Study

BACKGROUND

Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) induce effector memory T-cell expansions, which are variable and potentially depend on the age at primary exposure and coinfections. We evaluated the T-cell compartment and herpesvirus infections in 6-year-old children.

METHODS

T-cell subsets and immunoglobulin G seropositivity for CMV, EBV, herpes-simplex virus 1, and varicella-zoster virus were studied in 1079 6-year-old children. A random subgroup of 225 children was evaluated for CMV and EBV seropositivity before 2 years of age and for vaccination responses against measles and tetanus.

RESULTS

CMV and EBV infections were associated with significant expansions of CD27(-) and CD27(+) effector memory T cells, respectively. These expansions were enhanced in CMV-EBV-coinfected children and were independent of varicella-zoster virus or herpes-simplex virus 1 coinfection. Naive and central memory T-cell numbers were not affected, nor were anti-tetanus and anti-measles immunoglobulin G levels. Children infected before 2 years of age showed smaller effector memory T-cell expansions than those infected between 2 and 6 years of age.

CONCLUSIONS

CMV- and EBV-related T-cell expansions do not impair naive T-cell numbers or maintenance of protective responses against nonrelated pathogens. Duration of infection was not directly related to larger expansions of effector memory T cells in children, suggesting that other mechanisms affect these expansions at later age.

Increased association between febrile convulsion and allergic rhinitis in children: a nationwide population-based retrospective cohort study

BACKGROUND AND OBJECTIVES

Febrile convulsions and allergic rhinitis are both common childhood disorders and both are considered as generally benign disorders. Yet, especially in the case of allergic rhinitis, adverse effects on school performance and limited socialization are found. The relationship between febrile convulsions and allergic rhinitis has not been previously reported; thus, this article seeks to explore the association between these two disorders by collecting data from the Taiwanese nationwide cohort database.

METHODS

A total of 1304 children with febrile convulsions were identified as the case cohort, and controls were matched based on age, sex, urbanization levels, and parents' occupation on a 1 to 4 ratio. Cox's proportional hazards regression model was used to estimate the hazard ratio and confidence interval of allergic rhinitis disorder among children with febrile convulsions.

RESULTS

During an average 6.7 years follow-up period, the incidence of allergic rhinitis in the febrile convulsions case group was higher (65.16 vs 51.45 per 1000 person-years). After 11 years of follow-up, the allergic rhinitis incidence in the febrile convulsion patients was approximate 4% higher than controls (log-rank test P < 0.0001). Risk of allergic rhinitis in the febrile convulsions group was found to be 1.21 times higher than in the control group (95% confidence interval, 1.08-1.36). This risk of allergic rhinitis development is further increased (0.94 vs 18.9) with frequency of febrile convulsions-related medical visits (one to three visits vs more than three visits, P < 0.0001).

CONCLUSION

Febrile convulsions may be associated with allergic rhinitis occurrence in children. Children with more than three febrile convulsion-related medical visits had a significantly higher cumulative incidence of allergic rhinitis. Both disorders have previously been reported to have similar cytokine profiles and specific viral infection association. More studies are required to explore a possible link between the two disorders.

Long-term follow-up of de novo allergy in pediatric liver transplantation--10 yr experience of a single center

We conducted a study to clarify the incidence, clinical course, and risk factors of de novo allergies after liver transplantation. Ninety-three patients who had been followed longer than one yr and who had no previous allergy history were included. Forty-two patients (45.2%) developed de novo allergy. Of them, food allergy developed in 35 (37.6%). Respiratory allergy was observed in three (3.2%), and a patient (1.1%) had drug allergy. Fifty-two (55.9%) of the 93 patients developed eosinophilia. The median age of patients with de novo allergy was 15 months (IR 11.3-20 months). De novo allergy developed five months after liver transplantation (IR 2.3-9.5 months) and lasted for 16 months (IR 8-34.5 months). Younger age at liver transplantation displayed statistically significant differences in development of allergy between allergy and non-allergy groups. Twenty-nine (69.0%) patients improved from allergy during the follow-up period. No patient with de novo gastrointestinal allergy progressed to any respiratory allergy such as asthma. Older age at transplantation, EBV non-risk, and CMV non-risk had statistical significance in allergy improvement. Younger age at transplant predisposes to the development of allergy, while improvement of allergy is achieved more in older age.

Food allergy: temporal trends and determinants

This review summarizes studies discussing temporal trends in the prevalence of food allergy as well as potential factors associated with the development of food allergy. In addition, we will address the potential hypotheses accounting for the apparent increase in food allergy prevalence. Studies suggest increased prevalence of food allergy. However, relatively little is known about its pathogenesis. This review aims to assess temporal trends in the prevalence of food allergy and discuss potential genetic, environmental, and demographic determinants. The search strategy examined the medical literature database MEDLINE (using PubMed) for the time period of January 1, 2002 to January 31, 2012. In recent decades, the prevalence of food allergy in general has increased by 0.60 % [95 % confidence interval (CI), 0.59 %-0.61 %] and the prevalence of peanut allergy by 0.027 % (95 % CI, 0.026 %-0.028 %), but it has now likely stabilized in developed countries. Genes, the environment, and demographic characteristics play a role in the pathogenesis of food allergy. Numerous environmental and demographic factors as well as gene-environment interactions may account for this increase in prevalence, but further studies are required to tease out their relative contribution.

Immune modulation during latent herpesvirus infection

Nearly all human beings, by the time they reach adolescence, are infected with multiple herpesviruses. At any given time, this family of viruses accounts for 35-40 billion human infections worldwide, making herpesviruses among the most prevalent pathogens known to exist. Compared to most other viruses, herpesviruses are also unique in that infection lasts the life of the host. Remarkably, despite their prevalence and persistence, little is known about how these viruses interact with their hosts, especially during the clinically asymptomatic phase of infection referred to as latency. This review explores data in human and animal systems that reveal the ability of latent herpesviruses to modulate the immune response to self and environmental antigens. From the perspective of the host, there are both potentially detrimental and surprisingly beneficial effects of this lifelong interaction. The realization that latent herpesvirus infection modulates immune responses in asymptomatic hosts forces us to reconsider what constitutes a 'normal' immune system in a healthy individual.

Early-life EBV infection protects against persistent IgE sensitization

BACKGROUND

Infection with EBV has previously been implicated in influencing allergic disorders, but its precise role remains contradictory. The timing of primary infection may contribute to the discrepancies.

OBJECTIVE

This study aimed at investigating whether the time-point of primary EBV infection during childhood could be of importance in modulating the risk of developing IgE sensitization.

METHODS

A total of 219 Swedish infants were followed prospectively to 5 years of age with clinical examinations, skin prick testing, specific IgE analyses, and determination of serostatus against EBV.

RESULTS

After analysis of the children's EBV serostatus, we found that 5-year-olds who were infected with EBV before the age of 2 years were at a significantly lower risk of being persistently IgE-sensitized-that is, sensitized at both 2 and 5 years of age (adjusted odds ratio, 0.34; 95% CI, 0.12-0.94). In contrast, contraction of EBV after 2 years of age was highly associated with late-onset IgE sensitization (adjusted odds ratio, 4.64; 95% CI, 1.57-13.69). Persistently sensitized 5-year-olds had higher specific-IgE levels than children with late-onset IgE sensitization (P < .01).

CONCLUSION

Our data support the value of early-life microbial exposure for protection against the development of IgE sensitization and underscore the proximate postnatal years as an important period during which EBV could contribute to an allergo-protective immune profile.

Why is effective treatment of asthma so difficult? An integrated systems biology hypothesis of asthma

A hypothesis is presented that asthma is not only an airway disease, but that the disease involves the entire lung, and that the chronicity of asthma and asthma exacerbations can perhaps be explained if one considers asthma as a systemic disease. Increased lung-not only airway-vascularity may be the result of the action of angiogenesis factors, such as vascular endothelial growth factor (VEGF) and sphingosine-1-phosphate (S1P). A bone-marrow lung axis can be postulated as one element of the systemic nature of the asthma syndrome, in which the inflamed lung emits chemotactic signals, which the bone marrow responds to by releasing cells that contribute to lung angiogenesis. A molecular model of the pathobiology of asthma can be built by connecting hypoxia-inducible transcription factor-1 alpha, VEGF S1P, and bone-marrow precursor cell mobilization and acknowledging that angiogenesis is part of the inflammatory response.

Lactate dehydrogenase-elevating virus infection at the sensitization and challenge phases reduces the development of delayed eosinophilic allergic rhinitis in BALB/c mice

The present study was conducted to determine whether lactate dehydrogenase-elevating virus (LDV) infection at the sensitization and challenge phases affect the development of delayed allergic eosinophilic rhinitis induced by ovalbumin (OVA) in BALB/c mice (DAR group). Compared to the DAR group, LDV infection at the priming (DAR/LDVs group) and immunizing (DAR/LDVc group) phases reduced the induction of eosinophils in the bone marrow (BM) and/or blood. However, the number of eosinophils in the BM was not affected in the DAR/LDVc group. In addition, total blood IgE values were reduced in the DAR/LDVs but not the DAR/LDVc groups. Compared to the production of cytokines from splenic cells and blood IgE values in the DAR group, OVA-specific IL-4 and IFN-gamma productions and IgE values were reduced in the DAR/LDVs, whereas OVA-specific IFN-gamma and IL-4 productions were increased and decreased, respectively in the DAR/LDVc,but not the DAR/LDVs groups. Both DAR/LDVs and DAR/LDVc groups reduced the development of eosinophilic rhinitis associated with reduced VCAM-1 expression on endothelium in blood vessels and ICAM-1 expression on nasal respiratory epithelium at inflamed areas. The present study suggests that LDV infection at the sensitization phase may reduce the development of T helper (Th) 1 and Th2 responses, whereas LDV infection at the challenge phase may inhibit the development of Th2 response by shifting to Th1 response. These may be responsible for the reduction of the development of DAR by LDV infection.

The development of eosinophilic colitis after liver transplantation in children

Tacrolimus-based immunosuppression in pediatric liver transplant recipients is known to be associated with EGID. Our goal was to determine the incidence, risk factors, and characteristics of EGID in our pediatric liver transplantation program. This study was a retrospective analysis of 38 pediatric liver transplant recipients. Rectal mucosal biopsy was performed to evaluate for gastrointestinal PTLD and eosinophilic colitis. There were 14 patients (37%) who were diagnosed with eosinophilic colitis. The mean age at transplantation was 10.8 +/- 1.8 months. Those with eosinophilic colitis had a higher incidence of peripheral eosinophilia (p = 0.003) during the first two months following transplantation and had a higher EBV infection rate. Symptoms, such as diarrhea, hematochezia, and abdominal pain, became apparent after an average of three months; diagnoses were made at 6.9 +/- 2.0 months after transplantation. There were eight patients (57%) with elevated food-specific IgE levels. With food restriction treatment, the symptoms of patients improved. EGID should be considered when clinical symptoms are present, because symptoms of this disorder are similar to those of gastrointestinal PTLD. It should also be considered when peripheral eosinophila is detected or when EBV seroconversion develops during the first two months following transplantation.

Decrease of cytotoxic T cells in allergic asthma correlates with total serum immunglobulin E

BACKGROUND

Allergic asthma has been linked to an increase in T-helper type 2-like cytokines and T cells, but there is growing evidence for a role of lymphocyte-mediated cytotoxic mechanisms in the pathogenesis of asthma. Therefore, we investigated the cytotoxic potential of different lymphocyte subpopulations in patients with allergic asthma.

METHODS

Granzyme A, B, K, and perforin expression in peripheral blood lymphocytes was analyzed using flow cytometry. Soluble granzymes were measured in serum using specific enzyme-linked immunosorbent assays.

RESULTS

Asthmatics had significantly decreased percentages of granzyme and perforin-positive CD4 T cells compared with non-atopic controls. In patients with asthma, the granzyme B and perforin-positive subset of CD8(+) T cells and natural killer T cells, which represent more differentiated cell populations, were significantly reduced, while this was not observed in the less differentiated granzyme K(+) subsets. In addition, the serum concentrations of granzyme B were significantly reduced in patients with asthma, while granzyme K concentrations were not different. Interestingly, there was a negative correlation between granzyme A, B and perforin expression in T cell subsets as well as serum granzyme B concentrations and total serum immunglobulin E. In CD3-negative natural killer cells, no differences in granzyme or perforin expression between patients with asthma and controls were detected.

CONCLUSION

In allergic asthma, cytotoxic T lymphocyte subsets of a more differentiated phenotype are significantly decreased and this is correlated to serum immunglobulin E levels.

Changes in seroprevalence to four herpesviruses over 30 years in Swedish children aged 9–12 years

BACKGROUND

Changing social conditions and life-styles in Sweden may have affected the spread of varicella-zoster virus (VZV), herpes simplex virus (HSV), cytomegalovirus (CMV), and Epstein-Barr virus (EBV).

OBJECTIVES

To study possible changes over 30 years in prevalence of antibodies against VZV, HSV, CMV, and EBV in Swedish children, using modern serological methods.

STUDY DESIGN

Serum samples from 819 Swedish children who were 9-12 years old in 1967-1968, in 1977-1978 (two cohorts), and in 1997, respectively, were examined. IgG antibodies against VZV, HSV, and CMV were measured by well validated enzyme-linked immunosorbent assays and against EBV by indirect immunoflourescense.

RESULTS

The seropositivity for VZV for 9-12 years old children was 50% in 1967-1968, 74-82% in 1977-1978, and 98% in 1997. The corresponding figures were 31%, 53%, 50%, and 58% for CMV, 35%, 35%, 32%, and 38% for HSV, and 64% in 1967-1968 and in 1977-1978 (both cohorts), and 62% in 1997 for EBV.

CONCLUSIONS

The seroprevalence for VZV increased significantly from 1967-1968 to 1997, and there was also a significant but smaller increase in the CMV seroprevalence, while seroprevalence to HSV and EBV remained relatively stable.

Association between Chlamydia pneumoniae antibodies and wheezing in young children and the influence of sex

BACKGROUND

The proposed association between Chlamydia pneumoniae (Cpn) infection and wheezing needs further clarification.

METHODS

Serum samples obtained from 1581 children aged 4 years in a population based cohort were tested for antibodies to Cpn and IgE antibodies to common allergens. Data on environmental factors and disease were collected prospectively from birth.

RESULTS

The occurrence of IgG antibodies to Cpn at 4 years of age was associated with reported wheezing at different ages; however, these findings were most often not significant. In girls, the occurrence of anti-Cpn IgG was associated with wheezing at the ages of 1, 2, and 4 years (odds ratios (ORs) 3.41 (95% confidence interval (CI) 1.46 to 7.96), 2.13 (95% CI 1.02 to 4.44), and 2.01 (95% CI 1.14 to 3.54), respectively), and even higher ORs were observed for each age category when only high level antibody responses to Cpn were analysed. At the time of blood sampling the association between anti-Cpn IgG and wheezing was restricted to girls without atopic sensitisation (OR 2.39 (95% CI 1.25 to 4.57). No associations with wheezing were detected in boys, in whom IgE sensitisation was inversely associated with the presence of anti-Cpn IgG (OR 0.49 (95% CI 0.26 to 0.90)).

CONCLUSIONS

This study suggests an association between evidence of earlier Cpn infection and a history of wheezing in young girls. Infection with Cpn may be an important risk factor for wheezing and possibly for non-atopic asthma, predominantly in girls.

Does early EBV infection protect against IgE sensitization?

Background

There is indirect evidence that an increased infectious burden is associated with a decreased prevalence of IgE-mediated allergy during childhood.

Objective

To determine whether there is a relation between the serostatus of 13 different viruses and parentally reported infections and IgE sensitization in 2-year-old children. To investigate whether there is an interaction between cytomegalovirus (CMV) and Epstein-Barr virus (EBV) in relation to IgE sensitization.

Methods

A total of 246 infants were followed prospectively to 2 years of age with clinical examinations, skin prick test, and specific IgE analyses and through analysis of seropositivity against adenovirus, influenza, parainfluenza, respiratory syncytial virus, CMV, EBV, herpes simplex virus, human herpesvirus 6, and varicella-zoster virus.

Results

There was some evidence that IgE sensitization (24%) tended to be more common among children who were seropositive against few compared with children who were seropositive against many viruses, but this was not statistically significant, and there was no consistent trend across the groups. IgE sensitization was statistically significantly less prevalent at 2 years of age among infants who were seropositive against EBV but not other viruses (adjusted odds ratio, 0.34; 95% CI, 0.14-0.86). The interaction of seropositivity against both CMV and EBV antibodies indicated a further reduction in the risk for IgE sensitization (adjusted odds ratio for interaction, 0.10; 95% CI, 0.01-0.92), indicating effect modification associated with seropositivity against CMV.

Conclusion

Our results indicate that acquisition of EBV infection during the first 2 years of life is associated with a reduced risk of IgE sensitization, and this effect is enhanced by CMV coinfection.