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

Initiating pollen sensitization - complex source, complex mechanisms

The mechanisms involved in the induction of allergic sensitization by pollen are not fully understood. Within the last few decades, findings from epidemiological and experimental studies support the notion that allergic sensitization is not only dependent on the genetics of the host and environmental factors, but also on intrinsic features of the allergenic source itself. In this review, we summarize the current concepts and newest advances in research focusing on the initial mechanisms inducing pollen sensitization. Pollen allergens are embedded in a complex and heterogeneous matrix composed of a myriad of bioactive molecules that are co-delivered during the allergic sensitization. Surprisingly, several purified allergens were shown to lack inherent sensitizing potential. Thus, growing evidence supports an essential role of pollen-derived components co-delivered with the allergens in the initiation of allergic sensitization. The pollen matrix, which is composed by intrinsic molecules (e.g. proteins, metabolites, lipids, carbohydrates) and extrinsic compounds (e.g. viruses, particles from air pollutants, pollen-linked microbiome), provide a specific context for the allergen and has been proposed as a determinant of Th2 polarization. In addition, the involvement of various pattern recognition receptors (PRRs), secreted alarmins, innate immune cells, and the dependency of DCs in driving pollen-induced Th2 inflammatory processes suggest that allergic sensitization to pollen most likely results from particular combinations of pollen-specific signals rather than from a common determinant of allergenicity. The exact identification and characterization of such pollen-derived Th2-polarizing molecules should provide mechanistic insights into Th2 polarization and pave the way for novel preventive and therapeutic strategies against pollen allergies.

Hypersensitivity to aeroallergens in patients with nasobronchial allergy

Background:

Aeroallergens are the most common causes of allergy.

Aim:

The aim of this study was to determine hypersensitivity to aeroallergens in patients with nasobronchial allergy.

Methods:

This retrospective population study included 2254 patients with nasobronchial allergy, from late adolescents to adults. Their response to aeroallergens was assessed by skin prick tests.

Results:

More patients had rhinitis (72.7%), than asthma (27.6%). Although majority of patients were female, allergy is more common in men than in women (p<0.05). Both groups of patients had the greatest number of positive skin prick tests for Dermatophagoides pteronyssinus (27.5%) and weed pollens (21.9%), followed by grass (18.3%) and tree pollens (10.1%). Ragweed is the most common positive weed pollen in both groups, more in patients with rhinitis (p=0.022). The cocksfoot is the most common grass pollen in rhinitis group (15.3%), but meadow grass (12.6%) in asthma patients. Birch is the most common tree allergen in the both groups.

Conclusions:

More patients with nasobronchial allergy have rhinitis than asthma. Skin prick tests are usually positive for Dermatophagoides pteronyssinus and weed pollens, followed by grass and tree pollens, and they are more common positive in patients with rhinitis than asthma.

Detection of Cereal yellow dwarf virus using small interfering RNAs and enhanced infection rate with Cocksfoot streak virus in wild cocksfoot grass (Dactylis glomerata)

Small RNA sequences were obtained from leaf extracts of wild Dactylis glomerata (cocksfoot grass) using deep sequencing (454 Life Sciences, Roche Diagnostics), and were screened against virus sequences in GenBank using a local BLASTn search program (BioEdit). Putative small interfering (si)RNAs complementary in sequence to Cereal yellow dwarf virus (CYDV, genus Luteovirus) genomes were identified. Primer sequences were made against the "high scoring" siRNA sequences and RT-PCR was used to amplify a 438 bp CYDV fragment in total RNA extracts from D. glomerata leaves. Sequencing of the RT-PCR product confirmed the occurrence of a previously undescribed CYDV population with phylogenetic affinity to CYDV-RPS. In D. glomerata the CYDV infection rates were 42.3% (n=78) in 2008 and 50.0% (n=48) in 2009. Specific RT-PCR tests also showed that this D. glomerata population harboured Cocksfoot streak virus (CSV, genus Potyvirus). Dual infections by these viruses were observed in 20.5-22.9% of all plants tested in 2008-2009. Interestingly, infections of either CYDV or CSV enhanced the occurrence of the other virus in individual grasses. Opportunities are discussed for using siRNA sequencing approaches in virus survey and other ecology studies under field conditions.