New Sensitization In Respiratory Allergies Following Allergen Immunotherapy

Background Respiratory allergies are the most common chronic airway inflammatory diseases.Aeroallergens such as dust mite,pollen and molds are the driven factors of respiratory allergic diseases.Several studies have demonstrated that the allergic patients may develop new sensitization with a prolonged disease course.Allergen immunotherapy(AIT)is the only causal therapy for Ig E-mediated allergy and has a long-term effect after treatment cessation.Previous studies implied AIT can prevent allergic rhinitis from developing asthma.However,there is still lack of convincing evidence to demonstrate the preventive effect of AIT on the development of new sensitization.New sensitization during AIT may have a potential impact on the effect of AIT and the control of allergic disease.Therefore,identification of new sensitization at early stage of AIT will benefit the management of respiratory allergies.Objective 1.To investigate the allergen sensitization profile and risk factors of developing new sensitization in respiratory allergic patients receiving AIT.2.To investigate the time-to-developing new sensitization in respiratory allergic patients receiving AIT.Methods 1.Clinical data collection: The allergic rhinitis and /or asthma patients who receiving AIT for more than one year and having at least one SPT result after AIT initiation were enrolled in our study from 2011 to 2016.The data of cases included demographic characteristics and skin prick test results.The skin prick test panel included 19 common kinds of aeroallegens in our area,they were dust mite(Dermatophagoides farinae/Dermatophagoides pt eronyssinus,Df/Dp),grass pollens(Artemisia sieversi ana/ Ambrosi a artemisiifoli a/Humulus scandens,As/Ra/Hs),tree pollens(Populus cathayana/Cryptomeria fortunei/Platanus acerifolia/ Sabina chi nensis,Pc/ Cf/Pa/Sc),molds(Paecilomyces varioti/ Aspergill us fumigat us/Alt ernaria alternata/Cladospori um cladospori oides,Pv/Af/ Aaf/ Cc),animal dander(cat hair/dog hair/sheep hair/duck hair,C H/DH/Du H),Blatell a germani ca(Bg)and mulberry silk(Ms).2.Identification of t he risk factors of new sensitization in patients receving AIT: The factors,including age,gender,diagnosis and sensitization profile,were anal yzed for the effect on new sensitization.Binary Logistic univariate and multivariate regression were used.3.The survival curve of development of new sensitization: The patients who having four times SPT results(0.5 year,1.5 years,2.5 years,3 years)were included into survival analysis.The factors,including age,gender,diagnosis and allergen sensitization profile,were anal yzed for the effect on survival rate of new sensitization.The Kaplan-Meier method and Log-Rank test were used to anal yze survival rate.Results 1.A total of 1640 patients were enrolled in the study,649 were male and 991 were female.The median age was 17.7±15.1 years old.Amongst the patients,816 were allergic rhinitis,214 were asthmatics and 610 were allergic rhinitis complicated asthma.58.6% of the patients were mono-sensitized.House dust mites were the most common allergen,92.0% of the patients were sensitizing to Df,90.9% to Dp.After AIT,413(25.2%)patients developed new sensitization.The most common allergens of new sensitization included Bg(23.5%),Hs(17.2%)and CH(16.0%).2.Two risk factors of developing new sensitization in AIT were identified in the binary logistic univariate regress anal ysis.Patients with age≤6 years old was less to develop new sensitization compared to age﹥18 years old(OR=0.616,P=0.001),mono-sensitized patients were less to develop sensitization compared to poly-sensitized patients(OR=0.407,P ﹤ 0.001).However,the binary logistic multivariate regression analysis showed that only poly-sensitization was a risk factor to develop new sensitization in AIT(mono-sensitization vs poly-sensitization,OR=0.432,95%CI 0.342-0.545).3.A total of 134 patients were included into survival analysis,35 patients developed new sensitization.The average time of developing new sensitization was 1.4±1.1 years.The cumulative incidence of new sensitization at 0.5 year,1.5 year,2.5 year and 3.0 year were 14.2%,17.2%,18.7% and 26.1% respectively.The rate of developing new sensitization became slow along with time prolong,but the rate in 2.5-3 year became higher than that in 0.5-1.5 year and 1.5-2.5 year.K-M univariate anlysis showed that the survival rate of new sensitization was correlated to sensitization profile(mono-sensitization/poly-sensitization)at baseline(p=0.024).The rate of developing new sensitization in the mono-sensitized patients became slower than that in poly-sensitized patients along with time prolong.Conclusions 1.Around 1/4 of the respiratory allergic patients will develop new sensitization after receiving AIT.2.Compared to poly-sensitized patients,mono-sensitized patients have a lower probability of developing new sensitization after receiving AIT.3.New sensitization often occurs at early stage of AIT.With the prolonged procession of AIT,the rate of developing new sensitization is decreased gradually,but the rate at end stage is increased relatively.Poly-sensitized patients have a higher rate of developing new sensitization compared to mono-sensitized patients.