Immunotherapy

Why it is extremely important for an allergy patient?

Allergic disease is a complex disorder with the involvement of genetic and environmental factors. Sometimes it becomes a challenge to treat some of these patients. For instance,severe allergic rhinitis/difficult to treat asthma patients while conventional pharmacotherapy failed in controlling allergic symptoms or achieve the optimum result.

In that stage, mismanagement of these patients can cost/cause an irreversible damage and even life. To minimise this risk, an expert management and an alternative medicine are extremely important. While patients are diagnosed with uncontrolled asthma or rhinitis, they are advised for long term systemic steroids (oral or injectable) and which often have significant adverse impact in particular osteoporosis or avascular necrosis.

According to a study published in British Medical Journal in 2001, failure to refer a patient with uncontrollable hay fever to an allergist, cost with bilateral hip replacement. A male in his 40s, suffers with severe allergic rhinitis with uvular swelling, palatal irritation, profuse rhinorhoea, incessant sneezing, nasal obstruction, and conjunctivitis. While conventional drug therapy failed, his GP prescribed him an injectable depot corticosteroids for at least one a year totalled 16 injections over 10 years.immuno

As a consequence,this patient developed bilateral avascular necrosis of his hips, with the result that the patient was crippled and faces multiple bilateral hip replacements. At that stage he was referred to an allergist and was diagnosed after SPT as allergic to grass and tree pollens and his IgE level was extremely high. (325kU/L). He was offered grass pollen immunotherapy and the patient achieved a clear benefit.

Therefore, referral an allergic patient to an allergist and importance of alternative therapy are  essential and immunotherapy is one the treatment which has already taken this place for the past many years in the developed countries. However, this therapy is still not available in Bangladesh.


Immunotherapy:

It is a disease modifying treatment and some allergic patients can hope for cure. Many described this is the treatment closer to ' cure for allergy'. Small doses of allergen extract is administered to the patient either by injection or orally and the doses are increased gradually. Then it is maintained for a long period of time up to 5 years according to designed protocols. Gradual increasing allergens extract teaches the patient's immune system to develop tolerance to the specific allergens. There are some mechanisms involved in motivation of immune fighter off by induction of regulatory T cells (Treg), immune deviation (Th2 to Th1)suppressing Th2-mediated inflammation and increasing antigen-specific IgG etc. Therefore, specific immunotherapy reduces severity of allergic symptoms and need for medication significantly for many allergy patients and is documented as an effective treatment for respiratory allergy, wasp and bee venom allergy.

There are two types of specific immunotherapy available in the pharmaceutical market in developed countries and they are sub-cutaneous immunotherapy (SCIT) and Sub-lingual immunotherapy (SLIT). Many double-blind, placebo-controlled studies confirm, the efficacy of subcutaneous immunotherapy for treatment of allergic rhinitis, allergic asthma, and Hymenoptera, venom hypersensitivity. This can be administered by injection however, SLIT is considered more safe and convenient (oral administration)compared to the SCIT. Its use in particular is suitable for children. In 1998, World Health Organisation accepted in SLIT as an alternative to SCIT. In several meta-analyses, which concluded that SLIT is significantly efficacious compared with placebo for rhinitis and asthma in adults and children.This can be found as drops, spray and tablet and put under the tongue.

Referral of a patient to an allergist help the patient with phenotyping classification such as allergic, aspirin-sensitive and/or eosinophilic asthma and choose the appropriate management. Studies suggest that immunotherapy and anti IgE therapy are helpful in allergic asthma and leukotriene modifiers can be helpful for patients determined to be aspirin sensitive (who are often eosinophilic as well).
Immunotherapy has been documented in both children (not typically under 5) and adult. They are beneficial in the treatment of allergic rhinitis, asthma, insect stings. Ongoing research studies have indicated the efficacy of immunotherapy on atopic eczema and some food allergies though evidence is very limited.