Final answer:
Corticosteroids suppress the immune system by inhibiting lymphocyte production, leading to reduced immune responses and potentially increasing infection risk especially when used for conditions like asthma and COPD.
Step-by-step explanation:
The effect of corticosteroids on lymphocyte levels is generally immunosuppressive. These medications, which include drugs like cortisone, prednisone, and hydrocortisone, are known for their ability to downregulate the immune system. Their action inhibits the inflammatory response, which can be beneficial in treating various inflammatory or immunologically mediated disorders. However, they also reduce the body's immune response to infection by inhibiting the production of lymphocytes, which are white blood cells key to the immune system's ability to combat infections. For instance, corticosteroids can cause lymphocytes to leave the circulation and migrate to specific tissues, which can lead to abnormally low lymphocyte counts, a condition associated with chronic illnesses, immunosuppression, or therapies involving steroids.
Moreover, extended or excessive use of corticosteroids has been shown to have harmful effects on the immune system, such as a significant reduction in the number of circulating lymphocytes, increasing the risk of infection and complications in conditions like asthma and chronic obstructive pulmonary disease when under treatment with these drugs.