1. Historical origin of desensitization therapy.
Desensitization therapy has now been applied clinically for nearly 100 years. In 1911, the famous American allergist L. Noon was inspired by the Indian’s consumption of lacquer leaves to treat lacquer allergy, and for the first time used a small dose of pollen extract injection to treat hay fever allergic rhinitis successfully, thus creating a precedent for desensitization therapy.
2. Principle of desensitization therapy.
Although desensitization therapy has been applied for nearly 100 years, there are still some unexplored principles. In recent years, with the development of immunology and molecular biology, there has been a certain understanding of the mechanism of desensitization therapy from the cellular and molecular levels, and two of the more recognized points include.
① Generation of closed antibodies: Desensitization therapy causes the production of specific closed antibodies sIgG4 in the body, which can compete with sIgE, and when the allergen enters the body, it can compete with the allergen, thus preventing the binding of the allergen to sIgE and preventing the occurrence of subsequent reactions.
②Regulating the balance of T cells: Some studies have shown that prolonged desensitization therapy can change the balance of TH1/TH2/Treg cells in the body. Desensitization therapy inhibits the proliferative response of TH2 cells and enhances the effect of TH1 cells. After desensitization treatment, when exposed to allergens again, the body mainly produces TH1 cell reaction, TH2 cells are inhibited, and sIgE production is reduced, so that the allergic constitution is fundamentally corrected.
3. Comparison of desensitization therapy and drug therapy.
Desensitization therapy (treating the root cause)
Drug therapy (treating the symptoms)
Safety
In the past 22 years, there has not been a single case of anaphylaxis death in our laboratory, so desensitization therapy is relatively safe for allergic rhinitis.
Some drugs are cardiotoxic, but there are many highly effective and less toxic drugs available
Side effects
It is a biological treatment, except for temporary local redness, swelling, itching and pain during injection and minor systemic reactions, there are basically no side effects.
Some drugs have varying degrees of side effects, but there are many highly effective and low side effects drugs available.
Efficacy
80-90% of patients are effective in desensitization treatment, but the effect is slow
The effect is rapid and the maintenance time is short. Mostly in about 1 day. Long-acting hormones can last for about 1 month, but are not recommended for routine use
Cost
The cost is relatively high. However, in the long term, it has better cost performance compared with other treatments
High cost for those with high efficiency and low toxic side effects; low cost for those with heavy toxic side effects
Treatment time
Long treatment time makes it difficult for patients to adhere to the treatment. However, adherence to treatment can lead to more stable results
Immediate use of the drug can be effective. Symptoms may recur after stopping the drug
4, desensitization treatment of the appropriate population.
(1) Those who have strong positive inhalation allergen test.
(2) Those who are not effective with drug treatment.
(3) Children and adolescents with allergies are more suitable than adults because of better efficacy and prevention of new allergies and future aggravation of allergic diseases.
(4) Those with combined asthma or a tendency to develop asthma.
(5) People with severe exacerbations who cannot tolerate long-term medication and wish to obtain long-term stable results.
People who are not suitable or recommended for desensitization treatment.
(1) Those whose allergen tests suggest that the degree of allergy is not high.
(2) Those who cannot guarantee that desensitization therapy can be performed on time because of work or study.
(3) People with severe asthma attacks should not start desensitization during the attack. It should only be done after the symptoms are controlled and relieved.
(4) Women who are pregnant should not start desensitization therapy, but if desensitization therapy is first and pregnancy is second, desensitization can be continued after pregnancy.
(5) Other people who are not suitable for desensitization treatment.
5.Preparations for desensitization treatment.
The preparation used for desensitization must undergo strict production process and quality control. A series of processes from allergen extraction, purification, sterilization, quantification, etc. must be strictly quality controlled, otherwise it may affect the therapeutic effect or even cause complications and serious side effects.
Another very important aspect is the standardization of allergen preparations used for desensitization therapy. The purpose of standardization is to minimize the qualitative and quantitative differences between different batches of desensitization preparations. Because desensitization therapy is a sequential injection of desensitizing solution from low to high concentrations. If the composition and concentration of allergens fluctuate too much during injection, it is difficult for the immune system to form a good and orderly response, which can directly affect the efficacy of desensitization therapy and even cause serious local or systemic side effects.
6.Adverse reactions and side effects of desensitization treatment.
The adverse reactions and side effects of desensitization therapy are generally mild, mainly including.
(1) Local reactions: mainly erythema, swelling, papules, local itching, local pain and local hard nodules. Most of these reactions can be reduced and subside after local treatment with hot compresses, and it is generally not necessary to stop or adjust the injection volume. The higher the concentration level of injection and the higher the dose, the more local reactions occur, which is related to the strong stimulating effect of allergens.
(2) Systemic reactions: mainly urticaria or generalized pruritus, rhinitis and asthma symptoms after injection. The symptoms are usually not too serious and can be controlled after adjusting the injection dose and medication treatment, which does not affect the continuation of desensitization treatment. Individual patients may experience more severe asthma reactions with improper doses of desensitization therapy, and should promptly contact the specialist and adjust the desensitization dose accordingly.
Note: In some places, anaphylaxis caused by desensitization therapy was reported in the early years, but the causes were later analyzed to be mostly due to wrong dose or improper injection site, and anaphylaxis mainly occurs in patients with higher degree of allergy, mostly in asthmatic patients. Therefore, desensitization therapy is best performed by formally trained health care personnel. Particular attention should be paid to safety when desensitizing hypersensitive patients and asthma patients.
7. Role and efficacy of desensitization therapy.
Desensitization therapy can mainly achieve the following purposes.
(1) It can reduce the symptoms of allergic rhinitis and asthma.
(2) It can reduce the occurrence of new allergies.
(3) Reduce the chance of developing asthma in the future in patients with allergic rhinitis.
(4) Immediate efficacy is about 90% and long-term efficacy is about 75%.
The guarantee of the efficacy of desensitization treatment depends mainly on the following aspects: correct diagnosis by the doctor, correct choice of desensitization treatment plan, good desensitization preparation, correct and standardized operation, and cooperation of the patient.
Factors affecting the efficacy: inaccurate search for allergens, inaccurate diagnosis, unreasonable treatment plan, problematic desensitization preparations, irregular operation, poor patient cooperation or interference from other diseases of the patient’s body, etc.