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Why is this topic important?
People with myeloma, a type of bone marrow cancer, are more likely to get infections than people without myeloma.
Although treatments for myeloma have improved and many people now live longer, infections are still common and can be serious.
Infection remains one of the main causes of illness and death in people with myeloma.
Why the risk is higher
Myeloma weakens the immune system. The immune system helps the body fight germs.
Some treatments for myeloma can also lower the body’s ability to fight infection.
When the immune system is weaker, infections can develop more easily and may become serious more quickly.
Why this information is important
Knowing about this risk helps patients and caregivers:
- Recognise symptoms early
- Seek medical advice quickly
- Discuss infection prevention with their healthcare team
There have been many recent advances in the management of myeloma. As new treatments have emerged, this has led to improved outcomes for myeloma patients. However, despite this promising progress, infection remains a leading cause of death for myeloma patients. This is recognised in the myeloma community, and medical organisations have produced guidelines based on evidence to support doctors and nurses, patients and patient advocates to help manage the impact of infection on myeloma patients.
Myeloma itself leads to an increased risk of infection, but many myeloma treatments can also contribute to further increasing this risk. Some of the most recently developed and effective medications (directed at immune cells called T-cells) are associated with even higher infection risk. These include CAR T-cell therapies and bispecific antibody medications.
It is therefore important for myeloma patients and carers to be informed of these increased risks to empower them to make informed decisions about their care and be aware of the safety profile of these medications.
What is an infection?
An infection happens when harmful germs, such as bacteria, viruses, or fungi, enter the body and multiply. This can make you unwell.
Symptoms of an infection depend on the part of the body affected. Common signs include:
- A high temperature (fever)
- Feeling cold and shivering (shaking)
- Pain or tenderness
- Feeling very tired
- Feeling generally unwell
Infections are usually treated with medicines. Some infections can become severe and may require hospital care.
Causes of infection, otherwise known as pathogens, include viruses, bacteria and fungi. Infection happens when pathogens enter the body and begin to multiply, making you unwell. Infections can cause a variety of symptoms depending on where they are located. General symptoms of infection include fever, chills, pain, fatigue and feeling generally unwell. Infections are usually treated with medications called antimicrobial medications. Antibiotics, which fight bacteria, are a common example. Serious infections may require treatment in hospital.
How is myeloma related to the immune system?
The immune system protects your body from infections. It has different parts that work together:
- Some act quickly to fight germs (for example, the skin and certain blood cells)
- Others make a more targeted response by producing antibodies
Antibodies are proteins that help the body recognise and destroy germs. Myeloma affects plasma cells, which are responsible for making antibodies. When these cells become cancerous, they do not work properly. This weakens the immune system and increases the risk of infection.
The immune system protects the body from causes of infection. There are many parts of the immune system in different parts of the body. Some parts form the initial resistance against a pathogen. This is called the innate immune system. The innate immune system includes barriers to the outside world such as skin. It also includes some types of white blood cells such as neutrophils. These react to pathogens non-specifically to fight infection. Neutrophils and other innate immune cells are located throughout the body and blood, ready to react.
The body can also mount a more specific immune response to pathogens. This is called the adaptive immune system. The body does this using other types of white blood cells such as lymphocytes and plasma cells. Plasma cells are found in bone marrow (inside large bones) and certain other tissues. These cells form an immune response to pathogens by producing antibodies. These antibodies are proteins made to stick to the specific pathogen, marking them for destruction. Myeloma develops when normal plasma cells become cancerous and divide in an uncontrolled manner. These cells disrupt the normal function of the immune system and increase risk of infection.
Serious infections may require treatment in hospital.
Why does myeloma cause increased risk of infection?
Because myeloma weakens the immune system, the body is less able to fight infections. As a result, people with myeloma are more likely to get infections than people of the same age without myeloma, and infections can sometimes be serious.
This happens because:
- There are fewer infection-fighting cells
- These cells do not work as well as they should
- The body makes antibodies that do not work properly
Myeloma can also affect other parts of the body, such as the kidneys. This can make infections harder to recover from.
Myeloma has a direct impact on the function of the immune system. Having myeloma means that the normal response to infections is disrupted. Myeloma patients are more likely to get infections when compared to people of the same age without myeloma. The immune system of a person with myeloma is not as effective at fighting infection as those without myeloma. Infection remains a leading cause of death in myeloma patients.
In myeloma, there are often fewer immune cells, and these immune cells are less effective. The myeloma cells (cancerous plasma cells) are primarily located inside the bone marrow. The cells do not leave enough space for a normal number of plasma cells or other immune cells to be made in the bone marrow, because the myeloma cells grow out of control. Additionally, it has been observed that immune cells function less effectively due to myeloma. Myeloma cells try to produce an antibody, but the antibody produced does not help to fight infection. The non-functional antibody produced in excess by myeloma cells is known as M-protein or paraprotein.
Myeloma also causes other issues in the body that lead to increased risk of infection. Kidney problems can occur due to raised calcium levels (through bone being damaged by the myeloma cells). Also, the kidney’s delicate filtering tubes can become clogged with the paraprotein that myeloma cells produce. When the kidneys are damaged, the impact of infection tends to be higher.