Herpes simplex type I infection and atopy association in Turkish children with asthma and allergic rhinitis.

This study investigated the association between HSV-1 infection and atopy by comparing seropositivity to HSV-1 in atopic children with asthma and allergic rhinitis and in non-atopic children. Totally 249 children randomly selected from the university outpatient pediatric clinics were prospectively enrolled in the study between September 1 and November 30, 2007. Serum samples were examined using the virus neutralization test (VNT) for HSV-1 Immunoglobulin G(IgG) seropositivity. Skin prick tests (SPTs) were performed to determine atopic status. The results showed that HSV-1 IgG seropositivity was significantly higher in atopic children (56.8%) with asthma and allergic rhinitis than in the age-matched non-atopic children group (30.4%) (p<0.001). Although the occurrence of atopy was higher in seropositive girls (57%) than in seropositive boys (47%), the difference was not significant (p=0.329). These results support a possible relationship between the atopic status of children with asthma and allergic rhinitis and HSV-1 infection.

Proof of concept pilot study: prevalence of grass virus infection and the potential for effects on the allergenic potency of pollen.

BACKGROUND: Wild plants harbour a variety of viruses and these have the potential to alter the composition of pollen. The potential consequences of virus infection of grasses on pollen-induced allergic disease are not known. METHODS: We have collected pollen from Dactylis glomerata (cocksfoot; a grass species implicated as a trigger of allergic rhino-conjunctivitis) from Wytham Wood, Oxfordshire UK. Extracts were prepared from pollen from uninfected grass, and from grass naturally infected by the Cocksfoot streak potyvirus (CSV). Preparations of pollen from virus-infected and non-infected grasses were employed in skin testing 15 grass pollen-allergic subjects with hayfever. Allergen profiles of extracts were investigated by Western blotting for IgE with sera from allergic subjects. RESULTS: The prevalence of CSV infection in cocksfoot grasses sampled from the study site varied significantly over an eight-year period, but infection rates of up to 70% were detected. Virus infection was associated with small alterations in the quantities of pollen proteins detected by polyacrylamide gel electrophoresis, and in the patterns of allergens identified by Western blotting with IgE from grass pollen allergic subjects. For individual subjects there were differences in potencies of standardised extracts of pollen from virus-free and virus-infected plants as assessed by skin testing, though a consistent pattern was not established for the group of 15 subjects. CONCLUSION: Infection rates for CSV in cocksfoot grass can be high, though variable. Virus-induced alterations in components of grass pollen have the potential to alter the allergenic potency.

Rhinovirus infection preferentially increases lower airway responsiveness in allergic subjects.

Rhinovirus (RV) infections are important triggers of acute asthma symptoms in susceptible persons. To determine whether the presence of allergy is a risk factor for enhanced lower airway effects during RV infection, we experimentally infected (RV16) 18 volunteers with allergic rhinitis and 13 normal control subjects and measured the effects on the response of the lower airways to histamine. All subjects were successfully infected, as indicated by increased upper respiratory symptoms and RV16 cultured from nasal secretions. The change in histamine PD20(deltaPD20) caused by RV infection was significantly different in allergic subjects from that in nonallergic control subjects (deltaPD20 = -0.40 versus -0.03 log units, p = 0.04). This relationship was strengthened after adjusting for initial PD20 and FEV1 (mean deltaPD20 = -0.43 versus 0.01 log units, p < 0.01). The virus-induced deltaPD20 was also influenced by baseline lung function: there was a positive correlation between initial FEV1 and deltaPD20, and a weak but significant negative correlation between baseline PD20 and deltaPD20. These findings indicate that host factors such as allergy, baseline FEV1, and baseline PD20 influence the changes in lower airway physiology caused by RV infection and raise the possibility that these factors contribute to the increased lower airway effects of RV infection in subjects with asthma.