Validation Study of the OHIO Chamber in Patients with Japanese Cedar Pollinosis

Abstract

Background: An artificial exposure chamber (OHIO Chamber), which allows dispersal of a fixed concentration of Japanese cedar (JC) pollen under stable conditions, was constructed. This study was conducted to identify the exposure conditions assuring validity of the clinical tests conducted using this chamber. Methods: Twenty-four adult patients with JC pollinosis were exposed to different concentrations of JC pollen: 0 (only during the summer period), 4,000, 8,000 and 12,000 grains/m³, and the nasal and ocular symptoms were self-assessed during a 4-hour period of exposure. The amount of nasal discharge was measured and the sneezing frequency was recorded. This study was conducted twice during the summer and winter periods, i.e. non-pollen seasons. The reproducibility of the symptoms between the two seasons was assessed. Results: None of the subjects developed any symptom at the pollen concentration of 0 grains/m³. No significant differences in the time to the onset of symptoms were found between the summer and winter study, regardless of the pollen concentration. There were no significant differences between the summer and winter study in the total symptom score and total nasal symptom score at any pollen concentration, suggesting the very favorable reproducibility of symptoms. Conclusions: Efficient and reproducible results are obtained in patients exposed to JC pollen in the OHIO Chamber. The results suggest the conditions of JC pollen exposure have scientific validity and the OHIO Chamber has the potential to contribute significantly to basic and clinical studies of JC pollinosis.

Method for a homogeneous distribution of pollens in an environmental exposure chamber

“…Results of this study demonstrated that the system was able to deliver an average pollen level of 982 pollens/m 3 (SD, 102 pollens/m 3 ), close to the pre‐study target of 1000 pollens/m 3 . The variation was within what is generally accepted in other EEC studies . The spatial distribution of pollens varied by 9%, similar to what has previously been found .…”

Responses to ragweed pollen in a pollen challenge chamber versus seasonal exposure identify allergic rhinoconjunctivitis endotypes

“…Environmental exposure chamber studies can offer the advantage of inducing allergic rhinoconjunctivitis after exposure to pollen in the context of a highly controlled environment. [1][2][3][4][5][6] This strategy might potentially mitigate uncontrolled confounding factors that are inherent in phase III therapy trials conducted in sensitive subjects during the natural allergy season (eg, variable exposure to pollen or a short in-season period). 6 However, there are 2 key knowledge gaps that need to be bridged before this goal can be achieved.…”

Efficacy of fluticasone furoate nasal spray and levocetirizine in patients with Japanese cedar pollinosis subjected to an artificial exposure chamber

“…This facility can accommodate up to 14 subjects in one setting. The concentration of JC pollen and the exposure time were set at 8000 grains/m 3 (measured every 3 min by laser particle counter) and 3 h, respectively, according to the findings of a previous validation study23.…”

“…This rating system has been validated in the previous study23 and is different from that used in clinical trials in Europe and the US.…”