Immunocompromised conditions have many different causes. Some people are born with genetic disorders that affect immune function, such as severe combined immunodeficiency or common variable immunodeficiency. Others develop weakened immunity from diseases like HIV/AIDS, diabetes, or certain cancers including leukemia and lymphoma. Chronic kidney disease, liver disease, and malnutrition can also weaken the immune system over time.
Many medical treatments suppress immune function as a side effect. Chemotherapy and radiation therapy for cancer damage immune cells along with cancer cells. Organ transplant recipients take immunosuppressant medications to prevent rejection. Long-term use of corticosteroids for conditions like asthma or arthritis can weaken immunity. Age is also a factor, as immune function naturally declines after age 65. Lifestyle factors including chronic stress, poor sleep, smoking, and excessive alcohol use can further compromise immune health.