What Is a Compromised Immune System?

A compromised immune system does not work as well as it should because components are weakened or missing. Patients may develop immunocompromise, as it is known, as a result of medical therapies, underlying disease, or congenital conditions. As long as the immune system is not fully functional, the patient is at increased risk of infections and is less able to fight them off. Treatments are available to address these concerns, whether the immunocompromise is temporary or permanent.

Some patients have congenital immunodeficiencies, which means their immune systems do not work correctly because their bodies can’t make certain cells, or regulate immune function. In other cases, a compromised immune system is an acquired condition, caused by exposure to toxins, infections like the human immunodeficiency virus (HIV), or certain medications. Some drugs may suppress immune function as a side effect, seen with cancer drugs and some steroids. The benefits of treatment outweigh the risks, but the patient needs to be monitored throughout treatment.

Certain medical treatments may call for the deliberate induction of a compromised immune system. Patients preparing for transplants, for example, need to suppress their immune systems so they do not reject the transplant. They also need to take immunsuppressive drugs for life to prevent the onset of rejection. A temporary state of severe immune compromise may be induced just prior to a bone marrow transplant, where the donor marrow will eventually replace immune function.

Infectious organisms are more likely to catch hold in a patient with a compromised immune system, including rare organisms that do not usually cause disease in healthy individuals. The body lacks the defenses to identify and destroy bacteria, viruses, and other causes of disease. In addition, once an infection develops, the body is less able to suppress it. This means that an “ordinary” cold or flu could become severe, because the patient’s body doesn’t have the same adaptations as healthy people.

Patients may need to be isolated when their immune systems are particularly low. This could take place in a hospital or a secure home environment. Others may be advised to be careful about potential sources of exposure, such as young children who may carry a mix of viruses from the classroom, or foods known to carry infectious organisms. Medications may improve a compromised immune system in some cases, but they may need to be balanced against other health issues that could create contraindications, where using the medication would not be safe.