Asthma management: Blocking two immune system molecules can help prevent future attacks, suggests study

Asthma is a chronic respiratory disease that affects about 300 million people around the globe. In about 75 percent of all cases, asthma is triggered by an adaptive immune response (the one we develop after being exposed to an antigen) against certain allergens.Whenever an asthmatic person faces a trigger, their immune system recognises the trigger through memory cells, which then drive inflammation. Even though inhalers and anti-inflammatory medications help manage asthma attacks, so far there is no way to prevent an attack altogether.Now, a group of researchers at La Jolla Institute for Immunology, USA, claim that they have found two immune system molecules that, when blocked, can prevent asthma attacks in mice.The findings of the study have been recently published in The Journal of Allergy and Clinical Immunology.T cells and asthmaAsthma is driven by T helper cell (Th2) mediated inflammation in the lungs. T helper cells are specialised cells in the immune system that promote the release of type 2 cytokines and IgE (a type of immunoglobulin or antibody that mediates allergic responses in the body). Although type 2 cytokines have a protective role for the body, when dysregulated, they can lead to diseases.In our lungs, a specific type of T cells called Treg are responsible for maintaining tolerance to antigens (foreign substances against which our body mounts an immune response). It suppresses Th2 responses and thus helps in preventing lung and airway inflammation and the development of diseases like asthma.Several therapies targeting IgE and other effector cells of the immune system have been developed to manage asthma, though none of these are likely to affect the persistent memory Th2 cells. Memory cells are immune system cells that form when our body is first exposed to an antigen. It is these cells that help mount a quick and effective immune response when the same antigen enters our body for the second time.However, the authors of the latest study indicate that we still need a therapy that can prevent asthma attacks altogether and that is what this study aimed at.The studyFor the study, the researchers targeted two molecules: OX40L and CD30L. Both of these are signalling proteins that can activate T cells when the body is exposed to an allergen and hence lead to inflammation.Previous studies have suggested that blocking OX40L can reduce airway inflammation but it did not show any effects on memory response against the allergens. The experts had then decided that blocking OX40L was not enough and some other immune system molecule was involved in the process.So, in this study, they took mouse models who were allergic to dust mites and had either a missing OX40L or CD30L or both of these proteins absent.Here are some of the findings of the study:

• Absence of OX40L was found to be effective in reducing the initial response to an allergen but it did not have a major effect on the memory response when the body was exposed to the same allergen again.
• Absence of CD30L alone reduced some cytokine levels but it did not have a major effect on memory Th2 response. In fact, the effects of blocking CD30L was even less than that of OX40L when it came to suppressing memory response.
• Absence of both OX40L and CD30 together not only reduced the allergen-derived but also the memory Th2 response.

Based on the findings, the researchers suggested that blocking both OX40L and CD30 may be effective in reducing Th2 memory cells and hence preventing asthma attacks.For more information, read our article on Asthma. Health articles in Firstpost are written by myUpchar.com, India’s first and biggest resource for verified medical information. At myUpchar, researchers and journalists work with doctors to bring you information on all things health.