Factors that affect the allergic rhinitis response to ragweed allergen exposure

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

“…Most of our studied participants were either Hispanic white subjects or nonHispanic white subjects, and we found that race, age, sex, or skin test results to ragweed did not associate with symptom scores, whereas the symptom scores elicited in the PCC were strong determinants of the level of symptoms experienced during the natural season. Consistent with previous studies, [11][12][13][14] our study confirmed that the rate of symptom development or maximal symptom level achieved by participants exposed to ragweed pollen in the PCC or natural season was unrelated to the size of their ragweed skin test response. Together, these results substantiate Correlations were derived based on the maximum score recorded in each subject (n 5 26).…”

Clinical Validation of Controlled Grass Pollen Challenge in the Environmental Exposure Unit (EEU)

“…The symptom scores generated from the group exposed to 3500 grains/m 3 of grass pollen generally mirrored the responses seen previously with our ragweed pollen exposures, with some individuals reacting quickly with high symptom scores and others to a lesser degree [8]. The overall degree of symptomatic responses was also similar to those seen in ragweed sensitive subjects in a study conducted to evaluate the presence or absence of late phase allergic rhinitis responses to ragweed challenge in the EEU [19].…”

“…The overall degree of symptomatic responses was also similar to those seen in ragweed sensitive subjects in a study conducted to evaluate the presence or absence of late phase allergic rhinitis responses to ragweed challenge in the EEU [19]. In both of these studies, the mean TNSS at hour 3 was 8.6 to 9.2 with standard deviations of 2.0-2.1, respectively (8,19, data on file). The predictability of more rapid allergic symptoms achieved on the second day of pollen exposure may help to control for this variability, though no meaningful change in standard deviations between Day 1 and Day 2 data in the high or low concentration groups was observed.…”

“…The EEU has proven effective in multiple studies evaluating various aspects of seasonal allergic rhinitis and its treatments [4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Previous studies conducted in the EEU using ragweed pollen have shown 3500 grains/m 3 ± 500 to be an optimal concentration to produce symptoms similar to those experienced in the outdoor environment.…”

Nasal allergen challenge studies of allergic rhinitis: a guide for the practicing clinician

“…26 The effects of priming can be nonspecific. 25,27 For example, if a cat allergic participant is exposed to a cat before study entry (ie, already primed), the level of allergen required to activate their symptoms during a noncat allergen study would be lower than that required for a nonprimed person. Although studies that followed found similar effects, some reported the lack of the priming phenomenon, which may be attributed to the method of allergen introduction, evaluation of the response, or seasonal effects.…”