Chronic lymphocytic leukemia (CLL) is a type of cancer that affects white blood cells (WBCs). Since these blood cells are part of the immune system, CLL affects the body’s ability to fight germs.

CLL originates in the bone marrow, which is where stem cells develop and become any other type of cell.

CLL causes an increasing number of stem cells to grow into immature WBCs. Eventually, these atypical WBCs start crowding out the healthy ones, impairing a person’s immune system.

People with CLL have an increased risk of infection, autoimmune conditions, and severe complications from COVID-19.

This article explores CLL and the immune system. It also discusses how people with CLL can reduce their risk of infection.

A doctor and patient talking in an office, wearing masks due to the impact of CLL on the immune system.Share on Pinterest
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CLL affects the development of a type of WBC known as lymphocytes. These are part of the immune system and protect the body from viral, bacterial, and fungal infections.

However, when someone has CLL, their bone marrow produces atypical lymphocytes that do not function as they should. These immature cells cannot effectively protect against pathogens.

Over time, the atypical cells begin to crowd out healthy lymphocytes, reducing their ability to respond to infections. The atypical cells multiply more quickly and live longer. As this happens, a person’s immunity decreases, making infection more likely.

Besides an increased risk of infections, people with CLL can develop other complications, including Richter’s syndrome, also known as Richter’s transformation. This is a rare condition in which CLL suddenly transforms into an aggressive form of large cell lymphoma.

People can also develop other types of cancer, such as:

Up to 25% of individuals with CLL develop autoimmune complications, meaning their immune system mistakenly attacks healthy tissue. This usually involves the immune system attacking blood cells.

Doctors call this autoimmune cytopenia, and there are several forms:

  • autoimmune hemolytic anemia
  • immune thrombocytopenia
  • pure red blood cell aplasia

Autoimmune hemolytic anemia

If the immune system destroys red blood cells (RBCs) faster than the body makes them, health experts call this autoimmune hemolytic anemia.

Symptoms include:

Immune thrombocytopenia

When the immune system attacks the blood’s platelets, or clotting cells, doctors call this immune thrombocytopenia.

Symptoms include:

Pure red blood cell aplasia

In this rare condition, the bone marrow does not make enough RBCs, but the numbers of WBCs and platelets are within typical ranges.

People with pure red blood cell aplasia may experience symptoms such as fatigue and skin paleness.

A person with CLL is immunocompromised, meaning the condition weakens their immune system. As a result, their body is less able to fend off infections and other health conditions.

Moreover, some medications doctors use to treat CLL can affect how the immune system functions. Health experts call this immunosuppression.

Doctors may use targeted therapy to treat CLL. For example, Bruton tyrosine kinase (BTK) inhibitors can make changes to the immune system.

A person’s doctor can provide more information about whether their treatment plan will likely benefit their immune system.

It is important for people with CLL to take extra precautions to avoid acquiring infections, as they can be a common complication of cancer. Steps that may help include:

  • washing the hands frequently with warm water and soap, especially after using the bathroom, after touching animals, and before eating
  • using a hand sanitizer when washing hands is not possible
  • disinfecting surfaces, door handles, and cell phones regularly
  • avoiding large crowds of people
  • bathing every day
  • brushing teeth and flossing
  • cleaning cuts and scrapes and covering them with a bandage
  • avoiding animal waste and dirty diapers
  • avoiding hot tubs, ponds, and rivers
  • not sharing towels, toothbrushes, or utensils

It is not possible to fully restore the optimal levels of immune system health when a person has CLL. However, self-care can help support the immune system’s ability to work as well as it can during this time.

Individuals with CLL or other type of cancer can help boost the immune system in the following ways:

  • Getting enough sleep: Sleep deprivation suppresses the immune system, so a person should aim for 7 hours or more of uninterrupted sleep.
  • Eating a balanced diet: Consuming plenty of fruits, vegetables, and whole grains is helpful for immunity and overall health.
  • Getting enough physical activity: Physical activity and exercise boost the immune system. A person may prefer to begin by exercising for 10 to 15 minutes at a time to begin with.
  • Reducing stress: High levels of stress hormones, such as epinephrine and cortisol, suppress the immune system. Therefore, stress reduction activities, such as meditation, yoga, and massage, may help.

People with CLL may be more susceptible to COVID-19 because of the effects of CLL and the treatment-related immunosuppression.

Some studies show that almost 8 in 10 people with CLL who have COVID-19 develop serious symptoms requiring hospitalization. Of these individuals, around 3 in 10 die.

In a 2021 study following 941 people with CLL and confirmed COVID-19, the risk of mortality was higher for those who:

Individuals with CLL need to take special care to avoid coming into contact with those who may have SARS-CoV-2, the virus that causes COVID-19. People around them also need to ensure they follow safety precautions.

Chronic lymphocytic leukemia (CLL) refers to a cancer of the blood and bone marrow. It results in the growth of atypical lymphocytes that cannot fight infection. Lymphocytes are a type of white blood cell and are part of the immune system.

A person with CLL can help boost their immune system and lower their risk of infection by maintaining personal hygiene, eating a balance rich in fruits and vegetables, and engaging in regular physical activity.