What does it mean to be immunocompromised?

Most cancer patients and their caregivers will hear the word “immunocompromised” at some point.

But what does that actually mean? What causes someone to be immunocompromised? And why is it important to know if you are or not, especially during the coronavirus (COVID-19) pandemic?

We spoke with pulmonologist Scott Evans, M.D. Here’s what he had to say.

What does it mean to be immunocompromised?

The term “immunocompromised” is actually quite broad and relatively poorly defined. But generally speaking, it means someone’s immune system isn’t working as well as it should be to protect them against infections.

Being immunocompromised can lead both to worse illness from common infections and to increased susceptibility to uncommon infections, such as a Pneumocystis jirovecii.

What causes someone to become immunocompromised?

People can become immunocompromised for many reasons, including advanced age, metabolic disorders (such as diabetes), cancer treatments, and even cancer itself.

In cancer patients, being immunocompromised usually relates to the impairment of white blood cells, whether in number or function. Cancer often develops because the immune system fails to identify and eliminate abnormal cells. And in patients with blood cancers such as leukemia, lymphoma or multiple myeloma, the immune system may not function properly even if the person has a normal number of white blood cells.

Cancer patients who are preparing for a stem cell transplant are among the most vulnerable, as chemotherapy is intentionally used to reduce their immune function and then recover it with the transplant.

Are there different degrees of immunocompromization? Is there any type of scale that people can use to determine their own relative risk?

There’s really no universal standard scale for quantifying how immunocompromised someone is. But a particular type of white blood cell called a neutrophil can be one indicator of risk. This relationship was actually discovered here at MD Anderson back in the mid-1960s, and it was an incredibly important finding.

Gerald Bodey, M.D., and his colleagues showed that when neutrophil levels drop below 1,000 cells per microliter, patients’ susceptibility to infection goes up significantly. And if their levels drop under 500, patients’ risk goes up even higher. Low neutrophil counts are referred to as neutropenia.

The risk of contracting unusual infections goes up significantly in patients with AIDS, too, when their helper T-cell counts fall below 500.

Is there anything that can be done to treat immunocompromization clinically?

There are therapies we can give people to stimulate production of white blood cells called granulocytes, which includes neutrophils. We can also give people infusions of donated lymphocytes, another type of white blood cell.

But our main focus is treating the cancer, so that patients’ own immune function can be restored.

What challenges do immunocompromised patients face, and how can these be managed?

Many severely immunocompromised patients were already wearing masks prior to COVID-19, but outside the pandemic, many less-compromised patients don’t normally need to. They just have to engage in reasonable behaviors, such as avoiding sick people. Depending on the nature of a person’s particular immune dysfunction, certain hobbies, like gardening and spelunking, might put them at greater risk due to fungal exposure.

That being said, there is a huge discrepancy in immune function between individuals. So, it’s really best to talk to your own care team about your status and relative risk. Someone who has diabetes or cirrhosis of the liver is going to be at higher risk than the general population, but it’s still not going to be the same as someone who has just received a stem cell transplant. And different populations will have different germs that they’re susceptible to.

Some chemotherapies can have long-lasting effects on an immunocompromised patient’s system. Even 18 or 24 months after taking certain chemotherapy drugs, they can still see lingering side effects. So it’s important to talk to your care team about how long you should still take precautions, and which ones to continue even after treatment ends.

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