Anti-cytokine therapies can be used to target multiple steps in the allergic response. Blocking which of the following cytokines will reduce symptoms due to challenge by an allergen against which a patient has already been sensitized, but will not reduce sensitization to new allergens? IL-1 IL-4 IL-5 IL-13
The Correct Answer and Explanation is:
The correct answer is IL-5.
Explanation:
IL-5 is a cytokine that plays a critical role in the recruitment, activation, and survival of eosinophils, which are important immune cells involved in the allergic response. Eosinophils are involved in inflammation and tissue damage in response to allergens. When a patient is already sensitized to a specific allergen, blocking IL-5 can reduce the symptoms of an allergic reaction (such as asthma, rhinitis, or other allergic conditions) because it inhibits the function of eosinophils, which are responsible for much of the tissue damage and inflammation in response to the allergen.
However, IL-5 does not play a major role in the initial sensitization process to new allergens. Sensitization to new allergens primarily involves the activation of Th2 cells, which release IL-4 and IL-13. These cytokines are crucial for the differentiation of B cells into plasma cells that produce allergen-specific IgE antibodies, which are responsible for the sensitization process. Therefore, blocking IL-5 will not affect the initial sensitization to new allergens, as it does not interfere with the process of IgE production or the activation of Th2 cells.
In contrast:
- IL-4 and IL-13 are critical for the differentiation of Th2 cells and the production of IgE. Blocking these cytokines could affect both sensitization to new allergens and the ongoing allergic response.
- IL-1 is involved in the early stages of the immune response and inflammation, but it is not as directly involved in the allergic response as IL-4, IL-5, or IL-13.
Thus, targeting IL-5 specifically reduces symptoms due to challenge by allergens the patient has already been sensitized to but does not prevent sensitization to new allergens.
