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 Table of Contents  
ORIGINAL ARTICLE
Year : 2015  |  Volume : 29  |  Issue : 1  |  Page : 7-13

Inflammatory response to subcutaneous allergen-specific immunotherapy in patients with bronchial asthma and allergic rhinitis


Department of Respiratory Allergy and Applied Immunology, Vallabhbhai Patel Chest Institute, University of Delhi, New Delhi, India

Date of Web Publication17-Aug-2015

Correspondence Address:
Raj Kumar
Department of Respiratory Allergy and Applied Immunology, National Centre of Respiratory Allergy Asthma and Immunology, Vallabhbhai Patel Chest Institute, University of Delhi, New Delhi - 110 007
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0972-6691.162972

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  Abstract 

Background: Bronchial asthma (BA) and allergic rhinitis (AR) are chronic inflammatory disorders of the airways. The allergic response is driven by the production of different immunological effector cells cytokines like interleukin-5 (IL-5) and IL-6 among others. Subcutaneous allergen-specific immunotherapy (SCIT) modifies basic immunological mechanisms, reducing IL-5 production. The effect of SCIT on levels of IL-6 is undetermined. Objective: The aim is to study the changes in immunological parameters that follow SCIT in patients suffering from BA and/or AR. Materials and Methods: Twenty-nine patients (18-48 years, mean 25.5 years) diagnosed with BA and/or AR were evaluated for allergic sensitivity using skin prick test (SPT). The patients were started on standardized treatment for BA and AR as per global initiative for asthma and AR and its impact on asthma guidelines, respectively. SCIT was initiated as per the standard Indian guidelines. IL-5 and IL-6 levels were obtained at 0, 3 and 6 months during the course of SCIT and the response was evaluated using Friedman test. Results: Twenty-nine patients; 16 males and 13 females were evaluated and initiated on SCIT. The decreasing order of antigen sensitivity on SPT was mosquito (65.5%), housefly (58.6%), female cockroach (58.6%), male cockroach (48.2%), moth (34.4%) and house dust mite (17.2%). The IL-5 and IL-6 levels, for 0, 3 and 6 months were compared, and it was noted that with an increase in duration of treatment, the levels of inflammatory markers significantly decreases (P = 0.003). On comparison, the inflammatory response between male and female, duration of symptoms and number of positive antigens was not statistically significant. Conclusion: Immunologic changes associated with immunotherapy are complex and allergic patients suffering from asthma, and/or rhinitis showed a significant reduction in levels of inflammatory markers.

Keywords: Allergic rhinitis, bronchial asthma, subcutaneous immunotherapy


How to cite this article:
Kumar R, Gupta N, Bisht I. Inflammatory response to subcutaneous allergen-specific immunotherapy in patients with bronchial asthma and allergic rhinitis. Indian J Allergy Asthma Immunol 2015;29:7-13

How to cite this URL:
Kumar R, Gupta N, Bisht I. Inflammatory response to subcutaneous allergen-specific immunotherapy in patients with bronchial asthma and allergic rhinitis. Indian J Allergy Asthma Immunol [serial online] 2015 [cited 2017 Dec 14];29:7-13. Available from: http://www.ijaai.in/text.asp?2015/29/1/7/162972


  Introduction Top


The occurrence of allergic diseases such as bronchial asthma (BA) and allergic rhinitis (AR) has been on increasing trend all over the world including developing countries like India. It has been reported that 20-30% of world population suffers from an allergy, pollonosis alone accounting for 10-15% cases. [1],[2],[3]

Allergen immunotherapy (AIT) is defined as the repeated administration of specific allergens to patients with IgE-mediated conditions for the purpose of providing protection against the allergic symptoms and inflammatory reactions associated with natural exposure to these allergens. [4] The two most commonly prescribed routes for AIT are subcutaneous immunotherapy (SCIT) and sublingual immunotherapy.

Different immunological effector cells are responsible for allergic inflammation. [5] In humans, Th1 cells produce interleukin-2 (IL-2), interferon-gamma (IFN-γ) and possibly small amounts of IL-6, IL-10, and IL-13. On the other hand, Th2 cells produce IL-4, IL-5, IL-6, IL-9, and IL-13. Normally, Th1 cells support cell-mediated immune response and suppress the proliferation of Th2 cells, whereas Th2 cells support humoral and allergic responses. [6],[7] AIT acts by altering basic immunological mechanisms resulting in the suppression of the seasonal increase in eosinophilia, in the reduction of the late-phase reactivity and a shift from a Th2-to Th1-like response is initiated and maintained. [8],[9],[10],[11],[12],[13]

Hence, this study was undertaken to study the immunological changes that follow SCIT in patients suffering from BA and/or AR.


  Materials and methods Top


0Study design and demographics

The diagnosed patients of BA, AR and BA with AR (BA-AR) were enrolled for the study from the outpatient clinics. A total of 29 a topic subjects (16 males and 13 females) aged between 18 and 48 years were enrolled for immunotherapy, based on skin prick test (SPT) results for the purpose of analysis. The diagnosis of asthma and AR were based on the global initiative for asthma (GINA) [14] and AR and its impact on asthma (ARIA) [15] respectively. The exclusion criterion were: (1) Smoker (Former and current smokers) and (2) history of urticaria/eczema. All the 29 subjects underwent a battery of investigations including baseline spirometry and blood sampling. Written informed consent was obtained from all subjects. The study protocol was approved by Institutional Ethical Committee.

All 29 subjects were initiated on their BA and/or AR treatment as per the GINA and ARIA guidelines. SCIT, based on their SPT results was also initiated, and the subjects were followed-up. IL-5 and IL-6 levels were obtained from sera prior to initiation of SCIT and subsequently, at 3 rd and 6 th month of follow-up during immunotherapy treatment for the purpose of the study. The level of asthma control and medication requirement was noted at subsequent visits.

Spirometry with reversibility

Spirometry was performed on a dry, rolling-seal spirometer of the Benchmark model lung function machine (P. K. Morgan, Kent, UK). Maximal expiratory flow-volume curves were obtained as per the ATS recommendations. [16]

Skin prick testing

Skin prick testing to 58 common aeroallergens was performed in all the patients as per standard guidelines. [17] 58 different types of allergens, included five types of grass pollens (Cenchrus, Cynodon, Imperata, Pennisetum, Sorghum), 16 types of weed pollens (Adhatoda, Ageratum, Amaranthus spinosus, Argemone, Artemisia, Asphodelous, Brassica, Cannabis, Cassia occidentalis, Chenopodium album, Chenopodium M, Dodonaea, Gynandropsis, Parthenium, Suaeda, Xanthium), 11 types of tree pollens (Cassia siamea, Ehretia, Eucalyptus, Kigelia, Melia, Morus, Prosopis, Putranjiva, Ricinus, Salvadora, Holoptelia), 4 types of dusts (house dust, wheat dust, paper dust, cotton dust), 12 types of fungi (Alternaria, Aspergillus fumigatus, Aspergillus tamari, Candida, Cladosporium, Curvularia, Helminthosporium, Mucor, Phoma, Trichoderma, Rhizopus, Epicoccum), 6 types of insects (cockroach (M), cockroach (F), housefly, rice weevil, mosquito, moth) and others (house dust mite, kapok cotton, wool, silk) antigens. Atopy was defined as a positive SPT (wheal diameter of >3 mm as compared to buffer saline as control) for at least ≥1 aeroallergen. [17]

Subcutaneous perennial immunotherapy

The prescription for SCIT vials containing causative antigens was decided after correlating with history, evidence of exposure, precipitation of symptoms after exposure and skin test positivity. In cases where more than single antigen correlated with history, amount of individual antigen was decided depending upon their skin test positivity. More was the positivity; more was the amount of that antigen to be included in the vaccine. [17] In most of the cases, immunotherapy was started with 1:5000 w/v-diluted antigen and the injections were given 2 times a week starting from and increased by 0.1 ml in every injections. The injections were given subcutaneously or intradermally with a graduated syringe or insulin syringe. The idea was to achieve the highest maintenance dose, that is, 1:50 - 1-time a month, 1.0 ml. Usually the maintenance dose is between 0.5 and 1.0 ml of 1:50 dilution. [17] The complete schedule is labeled in [Table 1].
Table 1: Immunotherapy schedule of the patient*

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Measurement of serum interleukin-5 and interleukin-6

Serum levels of IL-5 and IL-6 were estimated by ELISA method using GENPROBE France, Diaclone kit as per manufacturer's instructions.

Statistical analysis

All data analysis was performed using SPSS statistical package version 16.0 for windows (SPSS, Chicago, Illinois, USA). The data were examined for distribution and homogeneity of variances was checked before applying parametric tests. The data on IL-5 and IL-6 were expressed as mean ± standard deviation. For comparing the inflammatory response markers (IL-5, IL-6) for 0, 3 and 6 months Friedman test was applied for k related samples. Mann-Whitney U-test and Kruskal-Wallis test were applied to compare response between the sub-groups. The conventional 5% level (P < 0.05) was considered to be statistically significant.


  Results Top


The demographic characteristics are shown in [Table 2]. Of the total 29 subjects, 16 were males and rests 13 were females. Overall there were 16 BA patients and 13 BA with AR patients in the study.
Table 2: Clinical profile of 29 patients undergoing SCIT

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Atopic profile

The various antigens positive on SPT were mosquito (65.5%), housefly (58.6%), female cockroach (58.6%), male cockroach (48.2%), moth (34.4%), rice weevil (31%), house dust mite (17.2%), cassia (3.4%) and prosis (3.4%). SCIT was initiated against single antigen in three subjects, two antigens in six subjects, three antigens in five subjects, four antigens in eight subjects and maximum five antigens in seven subjects [Table 2].

Interleukin-5 levels

The mean level of IL-5 at the baseline was 12.80 ± 13.09 pg/ml. The mean level obtained at 3 rd month was 9.64 ± 7.51 pg/ml and at 6 th month was 7.18 ± 4.88 pg/ml. The decrease in IL-5 level was statistically significant (P = 0.003) [Figure 1]. On analysis comparison of IL-5 levels at baseline between male and female, duration of symptoms (0-10, 10-20, 20-30, 30-40 years), number of positive antigens (≤2, >2) the mean response for each classification were not statistically significant [Table 3]. The mean level of IL-5 in-group classification according to number of antigen positive against, which SCIT were observed at initiation and in 3 rd and 6 th month of follow-up [Table 4].
Figure 1: Significant reduction in interleukin-5 (IL-5) and IL-6 observed during the treatment

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Table 3: Levels of IL-5 and IL-6 observed in various sub-groups of the study before initiation of SCIT

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Table 4: Levels of IL-5 and IL-6 observed in various sub-groups before and after 3 and 6 months following SCIT

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Interleukin-6 levels

The mean level of IL-6 at the baseline was 5.04 ± 1.35 pg/ml. The mean level obtained at 3 rd month was 4.32 ± 1.04 pg/ml and at 6 th month was 4.30 ± 1.13 pg/ml. The decrease in IL-6 level was statistically significant (P = 0.002) [Figure 1]. On comparative analysis of IL-6 levels at baseline between male and female, duration of symptoms (0-10,10-20, 20-30, 30-40 years), number of positive antigens (≤2, >2) the mean response for each classification were statistically insignificant [Table 3]. The mean level of IL-6 in-group classification according to number of antigen positive against which SCIT were observed at initiation and in 3 rd and 6 th month of follow-up [Table 4].

Asthma control and medication requirement

All BA and/or AR patients were evaluated for the compliance during the follow-up visits. BA patients had controlled asthma during the follow-up at 3 rd and 6 th month, with no requirement of additional oral corticosteroids for exacerbations and subsequently maintenance therapy at lowest controlling step was continued as per GINA guidelines. [14] In the assessment of AR, reduction in the requirement of oral anti-histamines was observed during the follow-up.


  Discussion Top


Allergy is one of the immune tolerance-related diseases that arise as a direct consequence of a dysregulated immune response. Allergen-specific immunotherapy has been used for more than 100 years in the therapy of allergic diseases. Currently, allergen-specific immunotherapy by the administration of increasing doses of allergen extracts remains the single curative approach to allergic diseases with the potential to modify its course. [18],[19] Subcutaneous SIT is able to decrease not only early, but also late asthmatic responses following allergen-specific bronchial challenge, thus confirming the anti-inflammatory effect of the treatment in the lung. [20]

Through previous two decades in India, a remarkable headway in research regarding characterization of various aeroallergens and the effectiveness of immunotherapy of significant value has occurred. [21],[22]

According to the GINA report, AIT should be considered only after strict environmental avoidance and pharmacologic intervention, including ICS. [14] The evidence for SCIT efficacy has been analyzed in the Cochrane review, which reported an overall clinical efficacy; that is, reductions in asthma symptom scores, medication usage, and allergen-specific bronchial hyperreactivity (BHR), and limited reduction in nonspecific BHR. [23] A recent meta-analysis of the effectiveness of SCIT in the treatment of AR and asthma concluded that SCIT reduces asthma symptoms and asthma medication usage. [24]

Epidemiological studies show that polysensitization is more prevalent in the general population. [25],[26] In a study by Kumar et al., [27] on pattern of skin sensitivity to various aeroallergens in patients of BA and/or AR in India, insects (43.90%) were the most common offending allergen, and among insects, the study reported moth (33%) as the most common cause. In the current study, the insects were the commonest causative allergen, with mosquito (65.5%) being a most frequent allergen.

In a review of the literature, studies have been performed with single allergens or cross-reactive allergen extracts in monosensitized patients and has been shown to be effective. [28],[29] However, the efficacy of multiallergen IT in polysensitized patients has been debated. Nelson [30] in his review of 13 studies on multi-AIT for AR and asthma concluded the simultaneous administration of more than 1 allergen extract is clinically effective. However, more studieSs are needed, particularly with more than 2 allergen extracts and with the sublingual administration. In the current study, the reduction in inflammatory markers (IL-5 and IL-6) was significant in both groups having number of positive antigens ≤2 and >2. Thus showing the efficacy of immunotherapy in subjects with more than 2 allergen extracts.

Wilson et al., [31] reported grass pollen immunotherapy leads to symptomatic improvement which correlates with reductions in eosinophils and IL-5 mRNA expression in the nasal mucosa during the pollen season. Immunotherapy induces transforming growth factor-beta, which is also a T-regulatory cell mediator [32] and is responsible for the down-regulation of the Th2 response-reducing IL-5 production [13] and preventing allergen-exposure-induced eosinophilia and inflammation. [31] In the present study, a statistically significant reduction in IL-5 and IL-6 levels was reported both at 3 and 6 months following initiation of allergen-specific immunotherapy. Karmakar et al. [33] in a placebo-controlled study on IT for 6-12 months with Cocos nucifera pollen extract showed significant clinical improvement (symptom-medication score), reduction in IgE and elevation of specific IgG in posttherapeutic patients' sera than placebo. Gaur and Gupta [34] similarly reported >50% improvement in clinical parameters (symptoms) after immunotherapy for 1-year in cases of asthma and/or rhinitis.

A double-blind placebo-controlled study [35] on IT with mosquito extract in asthma and AR patients demonstrated significant clinical improvement, supported with changes in airway reactivity and immunologic parameters (IgE, IgG1, IgG4 and IFN-γ) from the baseline and placebo. Similarly, a double-blind, placebo-controlled trial of cockroach IT [36] reported improved clinical and immunological status of asthma and rhinitis patients. A Clinico-immunologic study [37] on immunotherapy with mixed and single insect allergens concluded IT with two to three mix extract from the same allergen group is effective for insect hypersensitivity. Rasool et al. [38] reported a significant reduction in severity and medication requirements in cases of AR and BA following initiation of immunotherapy.


  Conclusion Top


Immunologic changes associated with immunotherapy are complex, and the exact mechanism or mechanisms responsible for its clinical efficacy are continually being elucidated.

In the current study of BA and AR patients, a significant reduction of inflammatory markers was observed during 6-month follow-up. However, a long-term study is required to elucidate clearly the response and effectiveness of immunotherapy.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
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