News Release

Title
Intranasal levels of lead as an exacerbation factor for allergic rhinitis in humans and mice
Key Points
A higher level of lead in nasal epithelial lining fluid (ELF) from patients with pollinosis
than that in ELF from control subjects was clinically obtained in season.

Correlations of lead levels in ELF with pollen counts as well as with severity of subjective
symptoms were obtained.

The clinical results
were partiallyconfirmed
by ouranimalstudy.
Intranasallevelsof leadas anexacerbation
factor forallergic rhinitis in humans and miceBackground
Detection of ahigh level of lead(Pb) in pollens

New findings
Clinical study
Control Patient with AR
Correlation between
pollen & Pb in ELFPbPbPbPb

Risk of intranasal
Pb for allergic
rhinitis (AR) ?

Conclusion<Pb PbPb Pb

Symptoms
Pb in ELF

Animal study
Control Mice with AR
PbPb<Symptoms
Pb in ELF
Pb in mucosa

PbPb
PbPb
Pb Pb

Symptoms of AR
Increased intranasal
Pb level caused bypollens could
exacerbate AR.

Summary
Air pollutants are suspected to affect pathological conditions of allergic rhinitis (AR). After
detecting lead (Pb) (375 μg/kg) in Japanese cedar pollen, the effects of intranasal exposure toPb on symptoms of AR were investigated. Pollen counts, subjective symptoms and Pb levels innasal epithelial lining fluid (ELF) was investigated in 44 patients with Japanese cedar
pollinosis and 57 controls from pre-season to season. Pb levels in ELF from patients were >40%
higher than those in ELF from control subjects during the pollen season but not before thepollen season. Pb level in ELF was positively associated with pollen counts for the latest 4 days
before visiting a hospital as well as scores of subjective symptoms. Intranasal exposure to Pb
exacerbated symptoms in allergic mice, suggesting Pb as an exacerbation factor. Pb levels in
ELF and nasal mucosa in Pb-exposed allergic mice were higher than those in Pb-exposed
non-allergic mice, despite intranasally challenging the same amount of Pb. Since the increased
Pb level in the nasal mucosa of Pb-exposed allergic mice was decreased after washing the nasal
cavity, Pb on the surface of but not inside the nasal mucosa may have been a source ofincreased Pb level in ELF of allergic mice. Increased nasal Pb level partially derived frompollen could exacerbate subjective symptoms of AR, indicating Pb as a novel hazardous air
pollutant for AR.
Research Background
The prevalence of seasonal allergic rhinitis, which is characterized by immunologicalreactions such as recruitment of eosinophils and release of cytokines, has been rapidlyincreasing. Seasonal allergic rhinitis has become a global health problem because of its highworldwide prevalence (10-30%). The prevalence of Japanese cedar pollinosis (JCP), arepresentative seasonal allergic rhinitis in Japan, has reached almost 50%, and JCP is now
called a folk disease in Japan.
Health disturbances caused by exposure to various elements including heavy metals havebeen widely recognized worldwide. In fact, it has been shown that elements modulate
immunological and inflammatory reactions. Notably, levels of lead (Pb), cadmium (Cd) andmercury (Hg), which are representative air pollutants, have been reported to increase the riskof bronchial asthma in the general population via modulation of immunological potencies andairflow obstruction. In the context of allergic rhinitis, studies have shown that pollen collectedfrom highly air polluted areas has more allergic potency than that of pollen collected from
unpolluted areas. However, there has been no clinical study showing the effects of heavy
metals on allergic reaction in the nasal cavity of patients with seasonal allergic rhinitis before
the season (pre-season) and during the season (season). Moreover, there has been noexperimental study showing effects of intranasal exposure to heavy metals on pathologicalconditions of allergic rhinitis.
In this study, we first hypothesized that the heavy metals in pollens affect the pathogenesisof JCP. Then a clinical follow-up study was conducted to investigate the contributions of heavy
metals to the pathogenesis of seasonal allergic rhinitis under the condition of natural allergen
exposure. To provide a more solid basis for a linkage between heavy metals and allergic rhinitis,the results obtained in human subjects were further confirmed by the results of a study using
model mice with allergic rhinitis.
Research Results
The Pb levels in ELF from patients were significantly
higher than those from controls in season, while the Pb
levels in ELF were comparable in patients and control
subjects in pre-season (Figure 1). Correlations between
each nasal symptom score and Pb levels in humansamples from patients in season were next investigated.
Spearman’s correlation analysis revealed significant
associations between Pb levels in ELF and scores forsneezing (r = 0.22, P = 0.026), nasal blockage (r = 0.34, P

Figure 1. Pb level in ELF.

= 0.001) and total subject symptoms (r = 0.25, P =0.013), while the score for nasal discharge (r = 0.12, P= 0.252) was not associated with Pb levels in ELF
samples. Log-transformed Pb levels in ELF remained
positively associated with incidences of sneezing (oddsratio [OR] = 5.27, 95% CI: 1.37~20.28, P = 0.016), nasal
blockage (OR = 7.67, 95% CI: 1.69~34.88, P = 0.008)
and total subjective symptoms (OR = 7.28, 95% CI:

Figure 2. Correlations of nasal
symptoms and Pb level in ELF.

1.88~28.20, P = 0.004) in multivariable models
adjusting for age, sex, BMI, smoking history,
sleep time and physical activity (Figure 2). The
correlations between the number of Japanesecedar pollen grains and Pb levels in humansamples in season were then investigated.
There were significant positive correlations
between pollen counts for 4 days before visitinga hospital and Pb levels in ELF (Table). Thissuggest that increased Pb level in ELF isTable. Correlations between Pb levels in ELF
and Japanese cedar pollen counts.

partially derived from pollen.
Thus, our clinical study suggests not only apotential source of intranasal Pb but also a
potential role of intranasal Pb as anexacerbator for activated allergic rhinitis inseason.
In order to confirm the results of ourclinical study, animal studies using micewith allergic rhinitis and mice without
allergic rhinitis were conducted with orwithout nasal challenge of Pb and/or theFigure 3. Pb exacerbates nasal symptoms in amouse model of allergic rhinitis.

antigen. Levels of symptoms (sneezing and nose rubbing) in mice without allergic rhinitis justafter nasal challenge of Pb were comparable to those just after
nasal challenge of the solvent of Pb (control). However, those inmice with allergic rhinitis just after nasal challenge of theantigen and Pb were significantly higher than those just after
nasal challenge of the antigen, indicating that nasal exposure toPb exacerbated nasal symptom of the mice with allergic rhinitis(Figure 3).
In control mice without allergic rhinitis, Pb level in ELF 24hours after the nasal challenge of Pb was comparable to that 24hours after the nasal challenge of the solvent of Pb. In mice withFigure 4. Pb level in ELF
from mouse model.

allergic rhinitis, the mean level of Pb 24 hours after nasal challenge of the antigen plus Pb was
8.4-fold higher than those 24 hours after nasal challenge of the antigen (Figure 4). More
importantly, the mean level of Pb in ELF from mice with allergic rhinitis 24 hours after nasal
challenge of the antigen plus Pb was 4.3-fold higher than that in ELF from control mice
without allergic rhinitis 24 hours after nasal challenge of Pb (Figure 4). Correspondingly, thePb level in nasal mucosa from mice with allergic rhinitis 24 hours after nasal challenge of theantigen plus Pb was higher than that nasal mucosa from mice without allergic rhinitis 24hours after nasal challenge of Pb in the condition before washing their nasal cavities (Figure 5).
Theseresults

intranasallysuggestthatchallengedPbremained at a high level in thenasal cavity 24 hours after nasal
challenge of Pb in allergic micebut not in non-allergic mice
despite the fact that allergic miceandnon-allergic

mice

were

intranasally exposed to the same

Figure 5. Distribution of Pb in nasal mucosa

amounts of Pb.
Research Summary and Future Perspective
A contribution of Pb adhering to pollen (an air pollutant) to allergic rhinitis could be aworldwide issue. Further allergotoxicologic studies are needed to clarify the molecularmechanisms of Pb-mediated exacerbation of allergic rhinitis and to qualitatively identify otherexacerbation factors for allergic rhinitis.
Publication
Journal: The Journal of Allergy and Clinical Immunology, 23 March 2021.
Title: Intranasal levels of lead as an exacerbation factor for allergic rhinitis in humans andmiceAuthor:
Huadong Xu1, Nobutaka Ohgami1, Masafumi Sakashita2, Kazuhiro Ogi2, Kazunori Hashimoto1,Akira Tazaki1, Keming Tong1, Masayo Aoki1, Shigeharu Fujieda2, Masashi Kato1
Affiliation:
1 Department of Occupational and Environmental Health, Nagoya University Graduate Schoolof Medicine, Japan.
2 Division of Otorhinolaryngology-Head & Neck Surgery, Department of Sensory andLocomotor Medicine, University of Fukui, Japan.
DOI: https://doi.org/10.1016/j.jaci.2021.03.019

Japanese Ver.
https://www.med.nagoya-u.ac.jp/medical_J/research/pdf/Al_Cli_Im_210330.pdf