Tightness of the chest, difficulty breathing, coughing, and wheezing -- a person suffering from allergic asthma can start experiencing all of these symptoms after inhaling an allergen. Though asthma affects about 340 million people worldwide, allergic asthma is the most prevalent form, with 90 percent of children with asthma having allergies, compared to 50 percent of adults with asthma.
Now, researchers led by Laurent Reber (Infinity, Toulouse) and Pierre Bruhns (Humoral Immunity, Institut Pasteur, Paris) and French company NEOVACS have developed a vaccine that could provide long-term protection against allergic asthma and reduce the severity of the symptoms, improving patient quality of life dramatically.
The vaccine aims to help alleviate the challenges faced by people with severe asthma since while inhaled corticosteroids can be used to control asthma, they are ineffective in severe cases. The use of therapeutic monoclonal antibodies is required in this situation, according to the researchers, but they are expensive and require long-term or even lifetime injection administration.
This is where the researchers decided to step in, developing a conjugate vaccine, called a kinoid, as reported in a research published in the journal Nature Communications.
Blockade of the cytokines
To give you a bit of background information, when a person with allergic asthma is exposed to allergy triggers, type 2 cytokines (such as interleukin-4 (IL-4) and IL-13) are produced in the airways, as well as antibodies called immunoglobulin E (IgE). This sets off a chain of events that results in hyper-responsiveness of the respiratory tract and excessive mucus production, among other things, Medical Xpress reports.
The researchers combined the recombinant cytokines IL-4 and IL-13 with a carrier protein named CRM197, a non-pathogenic mutant version of the diphtheria toxin used in most conjugate vaccines, to create the vaccine.
The results are promising: The vaccine induces the sustained formation of antibodies specifically directed against IL-4 and IL-13 in animal models, according to preclinical findings. 90 percent of the mice had high levels of antibodies six weeks after the first dose. After more than a year, 60 percent still had antibodies that could neutralize IL-4 and IL-13 activity.
The vaccine also showed an effect on asthma symptoms in a model of dust mite allergic asthma by strongly decreasing levels of IgE, eosinophilia, mucus production, and airway hyper-responsiveness.
The experiments were also performed on genetically modified mice that were designed to produce the human versions of the IL-4 and IL-13 cytokines, showing again positive findings for at least 11 weeks after vaccination.
All in all, these findings show that the vaccine, which had no adverse effects on the animals, is both prophylactic and preventive in this asthma model. The vaccine is yet to be tested in a clinical trial setting, but patients in Toulouse and Strasbourg might receive the first human injections in the next two years if all goes to plan. If this laborious step can be completed with triumph, people who are suffering from the chronic disease can finally take a fresh breath of air.