Pollen exposure weakens innate defense against respiratory viruses

Abstract

Background Hundreds of plant species release their pollen into the air every year during early spring. During that period, pollen allergic as well as non‐allergic patients frequently present to doctors with severe respiratory tract infections. Our objective was therefore to assess whether pollen may interfere with antiviral immunity. Methods We combined data from real‐life human exposure cohorts, a mouse model and human cell culture to test our hypothesis. Results Pollen significantly diminished interferon‐λ and pro‐inflammatory chemokine responses of airway epithelia to rhinovirus and viral mimics and decreased nuclear translocation of interferon regulatory factors. In mice infected with respiratory syncytial virus, co‐exposure to pollen caused attenuated antiviral gene expression and increased pulmonary viral titers. In non‐allergic human volunteers, nasal symptoms were positively correlated with airborne birch pollen abundance, and nasal birch pollen challenge led to downregulation of type I and ‐III interferons in nasal mucosa. In a large patient cohort, numbers of rhinoviruspositive cases were correlated with airborne birch pollen concentrations. Conclusion The ability of pollen to suppress innate antiviral immunity, independent of allergy, suggests that high‐risk population groups should avoid extensive outdoor activities when pollen and respiratory virus seasons coincide.

The EUMETNET AutoPollen programme: establishing a prototype automatic pollen monitoring network in Europe

“…The ultimate goal of AutoPollen is not only to establish long-term automatic pollen monitoring across Europe, but also to provide pollen observations and model forecasts to the public, medical practitioners, and health authorities for near real-time decision support (e.g. Gilles et al 2020). The cross-border Requires specialised staff, time-consuming Can be automatised to a certain degree, but may require human intervention on occasion…”

Biomarkers in the Diagnosis and Therapy of Allergic Diseases and Asthma

“…Like other chronic airway inflammatory diseases, AR patients also suffer from altered responses and potentially increased susceptibility towards viral infection. [107][108][109] This is similarly due to the reduced type III interferon response, which is crucial against incoming viral infection in the upper airway. [107][108][109] Hence, markers for virus induced AR exacerbation may have significant overlap with findings from other inflammatory airway diseases.…”

“…[107][108][109] This is similarly due to the reduced type III interferon response, which is crucial against incoming viral infection in the upper airway. [107][108][109] Hence, markers for virus induced AR exacerbation may have significant overlap with findings from other inflammatory airway diseases. Proinflammatory cytokines such as TNF-α, IL-4, IL-5, IL-13, RANTES, Eotaxin, TSLP, IL-25 and IL-33 are usually expressed at higher concentrations in chronically inflamed airways, some of which are also found in AR.…”

No SARS-CoV-2 detected in air samples (pollen and particulate matter) in Leipzig during the first spread

“…Moreover, pollen may interfere with antiviral immunity, e.g. pollen significantly diminish the epithelial response to rhinovirus infection ( Gilles et al, 2020 ). To date it is not known, if pollen allergy has an impact on the prevalence or severity of the SARS-CoV-2 pandemic.…”