Free Shipping on orders over $99

Allergen Immunotherapy in Asthma as a Treatment

Allergy, Asthma | December 12, 2014 | Author: The Super Pharmacist

allergy, Asthma

Allergen Immunotherapy in Asthma as a Treatment

Asthma is a respiratory condition in which the bronchi, or tubes leading from the throat to the lungs, may become constricted, thus restricting the ability to breathe in. This may lead to oxygen deprivation, discomfort, reduced quality of life and can be life-threatening. Asthma may occur in childhood or adulthood, and become a chronic condition. The symptoms of asthma may include:

  • Impaired air intake
  • Bronchospasm (i.e. the constriction of the smooth muscle found in bronchi and their subdivisions or bronchioles in the lungs)
  • Coughing
  • Wheezing or other forms of abnormal breathing
  • The presence of mucus in the airways, which may be coughed up

Asthma is associated with inflammation. This is a chemical process in the body that may increase the immediate temperature in areas where inflammatory molecules are released. This is done to destroy foreign bodies (or particulate matter from the environment) in the airways that may be present in inhaled air.

These inflammatory molecules are released by certain cells of the immune system, (e.g. eosinophils) which may be present in mucus. Asthma attacks (or the onset of this condition) may be triggered by many types of foreign bodies. These include:

  • Pollutants
  • Environmental allergens and irritants including pollen
  • Bacteria
  • Fungal spores

Some conventional therapies for many asthma types include:

Antibiotics

These are drugs that enhance the destruction of bacteria or fungi. However, long-term or high-volume use of these may result in adaptations in these micro-organisms that confer resistance to their actions. Therefore, recurrent infections may not be affected by the same antibiotics.

Antifungals

These are drugs such as triazoles which target fungi. These should only be used in cases of asthma definitively diagnosed as being associated with fungal species such as Aspergillus.

Corticosteroids

These are drugs that reduce inflammation, and therefore may treat pain and tissue damage in cases of asthma. They are associated with side-effects such as gastrointestinal distress and hormone response changes resulting in mood swings, weight gain or skin problems. Long-term corticosteroid use increases the risk of organ damage. Often these are used as inhaled corticosteroids, referred to as preventers, which reduces the systemic absorption, allows for a more potent localised effect, and reduces the incidence of previously mentioned side-effects.

Beta-agonists

These are drugs associated with the relaxation of smooth muscle tissue, referred to as relievers. These may be delivered by devices such as inhalers at the onset of airway constriction, and are popular in the treatment of asthma in children. Salbutamol is the most commonly used asthmatic treatment option.

Surgery

There are many types of surgical procedures available for cases of severe asthma, including bronchial thermoplasty. These may alleviate airway constriction, thus improving air-flow to the lungs and other symptoms. Normally reserved for severe cases.

Factors Affecting Asthma

Some factors may affect the progression of or recovery from asthma. These include:

Factors Affecting AsthmaObesity is linked to the increased severity of symptoms by some studies. Observations from these studies indicate that those who are obese and suffer from asthma, benefit less from treatment, find the control of their condition more challenging and require more healthcare resources in comparison to non-obese subjects. There is some evidence that weight loss leads to improvements in asthma symptoms and outcomes.

Non-adherence to treatment. This is associated with advanced cases of the condition in adults. Non-compliance may be related to common side-effects, some of which are outlined above, and the presence of comorbid (or additional and possibly associated) conditions.

Respiratory microbiome. There are a variety of different micro-organisms (e.g. bacteria) that normally inhabit the airways but do not adversely affect health, in a similar way to those found in a healthy gut.

This may be termed the respiratory microbiome. The microbiome has been found to be altered in patients with asthma compared to healthy people of similar demographics. This indicates that the normal balance of micro-organisms is disrupted or imbalanced in some cases of asthma, which increases the risk of the increased growth of micro-organisms that may cause damage or increased immune system activation. This may lead to further inflammation. Inflammation is associated with pain and damage to tissues which it affects. Therefore, asthma is often regarded as a disorder of innate immunity, and may require treatment as such.

Immunotherapy in Asthma

There are many treatments for asthma that focus on modulating or reducing the activities of the immune system in this condition. These include:

  • Anti-immunoglobulin antibodies: These are proteins, which may be synthetic or at least partially human, which bind to immunoglobulins such as IgE and inhibit their function. Immunoglobulins are molecules which locate micro-organisms and signal cells of the immune system to migrate to their location.
     
  • Methotrexate: This drug suppresses the immune response by inhibiting DNA synthesis in certain cells, activating cells that negatively regulate the immune system and inhibiting others that positively regulate it.
     
  • Antileukotriene drugs: Leukotrienes are a subtype of a class of molecules called cytokines, which also signal immune cells to relocate to their vicinity and release inflammation. They are associated with many respiratory conditions, including asthma.
     
  • Vaccines: These are components of allergens (e.g. surface molecules from bacteria or pollen) that are administered to generate a controlled immune reaction in the patient. These may include immune-system mechanisms that negatively regulate (or suppress) cytokines and/or immunoglobulins that signal eosinophils. Ideally, this leads to a competent immune response from the same complete foreign body in the future, but not undesired effects such as excessive inflammation.
     
  • Novel immunotherapy: These are relatively novel therapies still in development, or clinical trial stages in many cases, but show promise in cases of chronic asthma associated with specific triggers. Novel treatments include molecules such as complement proteins, adjuvants, peptides and DNA fragments.

Immunotherapy in AsthmaImmunotherapy may be administered in subcutaneous (under the skin), sublingual (under the tongue, usually in the form of drops or tablets) or intravenous forms. This may give long-term, constant-dose treatment for chronic forms of asthma. Immunotherapy is often specifically designed or prescribed based on the allergen (e.g. bacteria, fungi) that is responsible for the onset of asthma. However, they are associated with side-effects. These may include:

  • Gastrointestinal distress (e.g. diarrhoea, nausea, vomiting)
  • Systemic reactions such as itching, cough and shortness of breath
  • Serious, life-threatening events such as anaphylaxis, a condition in which many tissues exhibit severe swelling and blood pressure is reduced. This may be fatal unless treated.

These side-effects may restrict adherence to immunotherapy. A review of 23 clinical trials of sublingual immunotherapy found that the rate of side-effects in treatment groups ranged from 17% to 60%, in comparison to a rate of 8% to 14% in the corresponding groups receiving placebos. However, only two cases of anaphylaxis were found, which were in fact related to drug interactions with additional, non-trial medications.

A systemic review of 81 clinical trials with 9998 participants found that side-effects resulted in an overall drop-out rate of 14% (approximately 16% in the placebo groups and 17% for treatment groups).

These results indicate that immunotherapy may be tolerable for the majority of patients, but it should be noted that many of these trials monitored patients for a year or less, and this evidence does not often extend to post-market surveillance (which assesses adverse events and side-effects of drugs that have made it to the stage of commercial approval and use).

Immunotherapy may be highly specialised to individual cases of asthma, which could reduce healthcare resource use and medication reliance in the long term. However, many forms of this treatment are in need of further testing and development. Immunotherapy is associated with systemic reactions including anaphylaxis. However, the anti-IgE antibody omalizumab is associated with the prevention of these side-effects. This medication has been approved for use in Europe for cases of IgE-mediated asthma in children over six, adolescents and adults. It has been shown to treat asthma that is resistant to treatment with conventional medications such as corticosteroids effectively and safely.

www.superpharmacy.com.au  Australia’s best online discount chemist

References

Chung KF. Managing severe asthma in adults: lessons from the ERS/ATS guidelines. Curr Opin Pulm Med. 2015;21(1):8-15.

Khan MA, Nicolls MR, Surguladze B, Saadoun I. Complement components as potential therapeutic targets for asthma treatment. Respir Med. 2014;108(4):543-549.

Szlam S, Arnold DH. Identifying parental preferences for corticosteroid and inhaled Beta-agonist delivery mode in children with acute asthma exacerbations. Clin Pediatr (Phila). 2015;54(1):15-18.

Parulekar AD, Diamant Z, Hanania NA. Antifungals in severe asthma. Curr Opin Pulm Med. 2015;21(1):48-54.

Sivapalan P, Diamant Z, Ulrik CS. Obesity and asthma: current knowledge and future needs. Curr Opin Pulm Med. 2015;21(1):80-85.

Huang YJ. The respiratory microbiome and innate immunity in asthma. Curr Opin Pulm Med. 2015;21(1):27-32.

Passalacqua G, Durham SR, Global A, Asthma European N. Allergic rhinitis and its impact on asthma update: allergen immunotherapy. J Allergy Clin Immunol. 2007;119(4):881-891.

Smith TL, Sautter NB. Is montelukast indicated for treatment of chronic rhinosinusitis with polyposis? Laryngoscope. 2014;124(8):1735-1736.

Phillips JF, Lockey RF, Fox RW, Ledford DK, Glaum MC. Systemic reactions to subcutaneous allergen immunotherapy and the response to epinephrine. Allergy Asthma Proc. 2011;32(4):288-294.

Makatsori M, Scadding GW, Lombardo C, et al. Dropouts in sublingual allergen immunotherapy trials – a systematic review. Allergy. 2014;69(5):571-580.

Stelmach I, Sztafińska A, Woicka-Kolejwa K, Jerzyńska J. Omalizumab in the prevention of anaphylaxis during immunotherapy: a case report. Postepy Dermatol Alergol. 2014;31(3):191-193.

Kupczyk M, Kuna P. Omalizumab in an allergology clinic: real life experience and future developments. Postepy Dermatol Alergol. 2014;31(1):32-35.

backBack to Blog Home