Terry J. Walker

A post-hoc qualitative analysis of real time heads-up pollen counting versus traditional microscopy counting in the environmental exposure unit (EEU)

Background A custom digital imagery method for real time identification and counting of pollen was qualitatively evaluated in the Environmental Exposure Unit (EEU). Methods Airborne grass pollen was collected in the EEU via a Rotorod ® impact sampler. The pollen grains on each sampling rod were counted using both traditional and headsup microscopy. The heads-up technique incorporated a microscope camera to create an on-screen image of the sampling rod. Firstly, unique images were created by manually advancing the stage, without duplicating previously captured pollen grains. Well-defined, sharp images were obtained by fine focus and zoom combinations to enhance certainty and recognition speed. Secondly, using a custom application, each pollen grain was identified and counted on-screen by “point and click” or “screen touch”, simultaneously counting and permanently anchoring opaque dots to the pollen grain locations. Counts were stored in real time on a central database. Results Increased clarity of the polle ng rains resulted in higher counting accuracy. Duplicate counting of pollen grains was eliminated by digitally labelling counted grains. Additional need for manual counting devices, commonly associated with mechanical and human errors, was eliminated. Error free counts can be obtained with increased speed, therefore, improving the overall efficiency of the process and the EEU system as a whole. Conclusions This validated heads-up counting technique will allow for an increased response time to changes in the EEU pollen levels. This advancement could also enhance pollen counting processes followed by others using direct microscopy pollen counting techniques.

Lack of effect of Grastek® on birch pollen-induced allergic rhinoconjunctivitis in the Environmental Exposure Unit

BACKGROUND Timothy grass pollen allergen extract tablets (Grastek) are standardized sublingual immunotherapy tablets (SLIT-T) approved for the treatment of grass pollen-induced allergic rhinitis (AR) and conjunctivitis. Many grass allergic patients are also cosensitized to birch pollen. Whether Timothy grass SLIT-T can confer symptomatic benefits for birch pollen-induced AR symptoms is unknown. OBJECTIVE To evaluate the treatment effect of Timothy grass SLIT-T for birch pollen-induced AR in participants sensitized to both grass and birch pollen using an environmental exposure unit (EEU). METHODS This study was a phase 4, randomized, double-blind, placebo-controlled, parallel-group study that enrolled participants aged 18 to 65 years allergic to both timothy grass and birch pollen. After a baseline EEU birch pollen challenge, in which a minimum total nasal symptom score (TNSS) of 6 of 12 was required for enrollment, participants were randomized to receive Timothy grass SLIT-T or placebo taken once daily for 4 months. No confirmatory grass pollen challenge was performed. The primary end point was the change in TNSS averaged from assessments from hours 2 to 5 during the posttreatment birch pollen challenge compared with baseline. The secondary and exploratory end points included temporally identical changes in total ocular symptom score (TOSS), total rhinoconjunctivitis symptom score (TRSS), and individual symptom scores. RESULTS The difference in TNSS reduction after 4 months of therapy between the Timothy grass SLIT-T and placebo group was not significant (P = .83). Reductions in TOSS (P = .19) and TRSS (P = .67) were also comparable between groups. Findings between groups for individual symptom scores were similar (all P > .40), except for watery eyes, in which symptom reduction was slightly better in the placebo arm (P = .01). Timothy grass SLIT-T was well tolerated, and no serious adverse effects occurred. CONCLUSION A bystander effect of grass SLIT-T on birch pollen-induced AR symptoms was not detected. Symptomatic benefits of grass SLIT-T are likely allergen specific. TRIAL REGISTRATION ClinicalTrials.gov identifier: NCT02394600.

Retraction Note: Meeting Abstract: A post-hoc qualitative analysis of real time heads-up pollen counting versus traditional microscopy counting in the environmental exposure unit (EEU)

Retraction This meeting abstract [1], published in the Canadian Society of Allergy and Clinical Immunology and AllerGen Abstracts 2014 supplement, has been retracted from Allergy, Asthma & Clinical Immunology by the authors. The meeting abstract has previously been published in Journal of Allergy and Clinical Immunology [2] and was inadvertently submitted to Allergy, Asthma & Clinical Immunology as part of the supplement. The authors apologise for any inconvenience that this may have caused.

An overview of the advanced data collection techniques in the environmental exposure unit (EEU)

Methods Advanced scanning technologies are used with a customized two-step quality assurance data collection process. Optical Mark Recognition (OMR) and Optical Character Recognition (OCR) capture data from paper symptom diary cards into the EEU’s clinical data management system (CDMS). A template is configured to read the static diary card format and assign zones where the specific diary card data are located. The user configures field requirements within the zones to validate data captured. Cards that do not meet a predefined confidence level for any particular zone will be flagged for a quality check. The quality checking process involves one user visually confirming all data captured and a second user inputting all values from the card to ensure accuracy. Invalid data are rejected from the batch and returned to the participant for correction. Corrected cards are scanned again and all valid data are transferred into the CDMS.