Investigation Of Aeroallergens Among Rhinitis Patients In The Steppe Environment Of Inner Mongolia

Objective: To determine the sensitizing aeroallergens among patients withrhinitis in the steppe environment of Inner Mongolia, to evaluate the correlation ofexposure and sensitization to house dust mites, to compare the influence of individualcharacteristics (sex, age and nationality) in the etiology of allergic rhinitis (AR) andnon-allergic rhinitis (NAR), to discuss the clinical diagnosis value of the allergentesting in vivo and in vitro, and to provide reference for the diagnosis and preventionstrategy of rhinitis in the steppe region.Methods: Three hundreds and fourteen patients with rhinitis symptoms wererecruited in this study for a short time in Xilinhot, Inner Mongolia. All patients wereaccepted medical history investigations and anterior rhinoscope checks. Theycompleted standardized questionnaires and underwent serum measurement ofeosinophil cationic protein (ECP) and total IgE (tIgE). Skin prick test (SPT) andserum specific IgE (sIgE) to common aeroallergens were performed. Dust sampleswere obtained from some patients’ mattresses. The concentrations of group1allergenof Dermatophagoides pteronyssinus (Der p) and Dermatophagoides farinae (Der f)were measured by ELISA. Statistical analysis was performed using a SPSS17.0software.Results:①A mong314patients,the age range were5to70years old, with anaverage age of (30.14±14.18) years old.125cases (39.8%) were males, and89cases(60.2%) were females.195cases (62.1%) were Han nationality, and119cases (37.9%) were minority nationalities.②The positive rates of SPT for11kinds ofaeroallergens were follow: mugwort (52.2%), ragweed (31.2%), timothy grass(26.4%), birch (24.2%), Der f (21.9%), Blomia tropicalis (17.5%), dog dander(12.7%), cat dander (11.8%), German cockroach (9.2%), Alternaria alternate (8.3%),and Der p (5.7%). The positive rates of serum sIgE for these aeroallergens werefollow: mugwort (47.1%), ragweed (34.7%), birch (21.3%), timothy grass (19.7%),Der p (9.2%), cat dander (8.0%), Der f (7.6%), German cockroach (7.3%), dogdander (6.7%), Blomia tropicalis (6.4%), and Alternaria alternate (4.5%).③Samplesof dust were collected from276patients’ mattresses. The levels of Der p1weredetectable in two samples (0.7%) and Der f1in four samples (1.4%). The largestconcentration of Der p1and Der f1was162ng/g and532ng/g, respectively. ForDer p, there was positive correlation between exposure levels and SPT positivereactions (rs=0.156, P=0.010), but no significant correlation between exposurelevels and sIgE positive reactions (rs=0.116, P=0.055), by using Spearman rankcorrelation analysis (α=0.01). Exposure levels of Der f were not correlated with SPT(rs=0.05, P=0.931), as well as sIgE (rs=0.070, P=0.24).④Among rhinitis patients,the positive rates of SPT, serum sIgE, tIgE, and ECP were higher for males thanfemales (all, P <0.05), and showed a linear degressive tendency with increased age(P=0.000). But there were no significant differences between the nationality and theprevalence of positive SPT, serum sIgE, tIgE, and ECP (all, P>0.05).⑤207cases(65.9%) were diagnosed with AR, with male patients accounted for44.4%(92cases),and female patients55.6%(115cases).107cases (34.1%) were diagnosed with NAR,with male patients accounted for30.8%(33cases), and female patients69.2%(74cases). The highest morbidity age in AR patients was10~19years in males, and30~39years in females. On the other hand, the highest morbidity age in NAR patientswas30~49years in females, and no significant peak age in males was found.⑥For detection of sensitization to every aeroallergen, there was a consistency between theallergen testing in vivo (SPT) and in vitro (sIgE). Its intensity was highest formugwort followed by for cat dander, and was lower for Der f, Der p and Blomiatropicalis. The detection of serum sIgE against all of the tested allergens showed agood specificity as well as negative predictive value (both,>80%).Conclusions: In the steppe environment of Xilinhot, Inner Mongolia,65.6%of patients with rhinitis might be related to allergic sensitization, and mugwort is themajor aeroallergen. Exposure and sensitization to house dust mites are very low inthis special environment. Importantly, it is not a simple dose-reaction relationshipbetween exposure and sensitization to house dust mites. Among rhinitis patients, thepositive rates of SPT, serum sIgE, tIgE and ECP show a linear degressive tendencywith increased age. The positive rates of these parameters are higher in males than infemales, but not by the nationality influence. In rhinitis patients, men are more likelyto be AR than women. The highest morbidity age in AR is between10~19years inmales. In contrast to AR, females have a significant trends for suffering from NAR,and the highest morbidity age is between30~49years. For clinical diagnosis, we canchoose a detecting method in vivo or in vitro for the mugwort and cat allergens, andSPT is firstly recommended. And for the other aeroallergens, it is recommended thatthe in vivo and in vitro testing should be used combined, in order to improve theaccuracy of diagnosis.