Light chain multiple myeloma is a subtype of multiple myeloma, a cancer of the plasma cells in bone marrow.
Multiple myeloma is a rare type of cancer that occurs when plasma cells in bone marrow become cancerous and multiply.
There are different types of multiple myeloma, depending on the type of antibody the plasma cells produce. These antibodies, or immunoglobulins, consist of light and heavy chain proteins.
Light chain myeloma is a subtype of multiple myeloma, in which the immunoglobulins only consist of light chain proteins. This can affect symptoms, treatment types, and outlook.
This article looks at what light and heavy chains are and how light chain myeloma differs from other types of multiple myeloma.
Multiple myeloma is a rare type of cancer that occurs due to plasma cells becoming cancerous. Plasma cells are a type of white blood cell found in bone marrow, and they help protect against infections.
The term for a cancerous plasma cell is a myeloma cell. These cells can multiply, and excessive plasma cells may group together to form a tumor.
If there are multiple tumors or the bone marrow contains a significant number of cancerous plasma cells, the condition is called multiple myeloma.
There are different types of multiple myeloma. The type depends on the immunoglobulin that a myeloma cell produces, also known as antibodies or M-proteins.
According to the International Myeloma Foundation, immunoglobulins (Ig) usually consist of two heavy chain proteins and two light chain proteins joined together.
Myeloma cells produce abnormal immunoglobulins called monoclonal proteins, or M-spike, which cannot fight infection in the same way as regular immunoglobulins.
There are five types of heavy chain proteins:
There are two types of light chain proteins: kappa and lambda. Light chain proteins are
Subtypes of myeloma are categorized based on:
- the type of immunoglobulins they produce
- the combination of heavy and light chains the immunoglobulin contains
The types of immunoglobulins are:
- IgG kappa
- IgA kappa
- IgD kappa
- IgE kappa
- IgM kappa
- IgG lambda
- IgA lambda
- IgD lambda
- IgE lambda
- IgM lambda
The most common type of myeloma is IgG kappa. This means the myeloma cells produce immunoglobulins made of two IgG heavy chains and two kappa light chains.
Roughly 15% of people with multiple myeloma have light chain myeloma.
Light chain myeloma occurs when the myeloma cells only produce immunoglobulins with light chain proteins and no heavy chain proteins.
According to a
People may also refer to light chain myeloma as Bence Jones myeloma after the doctor who discovered this subtype of multiple myeloma.
The most common symptoms of multiple myeloma are:
- persistent or frequent bone pain or back pain
- persistent or worsening fatigue
- frequent, unexplained infections, such as sinus infection, pneumonia, or urinary tract infection
- swelling in the extremities
- shortness of breath
In addition to multiple myeloma symptoms, people with light chain myeloma may also experience:
- numbness in limbs
- loss of appetite
- impaired kidney function
- excess calcium in the blood
- bone damage
To diagnose multiple myeloma, doctors will assess any symptoms, take a full medical history, and use a range of tests, including:
- blood tests to check white and red blood cell counts
- urine tests to check for elevated levels of M-proteins, as excessive plasma cells can lead to higher levels of M-proteins than usual
- bone marrow samples to examine plasma cells
- imaging scans, such as MRI and CT scans, to look for any changes in the bones
These tests can help doctors identify signs that could indicate multiple myeloma, such as:
- kidney failure
- bone damage
To diagnose the subtype of multiple myeloma and determine whether a person has light chain myeloma, doctors may:
- test urine or blood for the presence of light chains
- check for deposits of light chains in the kidneys or nerves
Light chain multiple myeloma does not create the spike in M-proteins that can be a feature of other types of multiple myeloma, so doctors look for an excess of light chains and the absence of heavy chains.
Treatment for multiple myeloma may include:
- chemotherapy to decrease the number of myeloma cells
- antibiotics to fight infection
- pain-relief medications
- radiation therapy to destroy cancer cells or any bone tumors
- biologic drugs
- intravenous fluids if necessary to prevent dehydration from kidney failure
- stem cell transplant
Treatment may vary depending on a person’s overall health, age, and medical history.
According to the Dana-Farber Cancer Institute, doctors usually recommend the following approach to treatment:
- initial induction phase
- intensified treatment, including an autologous stem cell transplant for people who fit certain criteria
- maintenance therapy
- treatment for relapsed disease
Doctors often prescribe a VRd drug regimen to treat multiple myeloma. VRd includes:
- a proteasome inhibitor — Velcade
- an immunomodulatory agent — Revlimid
- a corticosteroid, such as dexamethasone
Light chain amyloidosis can affect any organ in the body except the brain, and commonly affects the kidneys and heart.
Treatment for light chain amyloidosis may include:
- a protein called albumin
- vasopressors, a type of drug to increase blood pressure to prevent organ damage
Having light chain myeloma may affect a person’s outlook compared to other types of multiple myeloma.
According to a 2021 article, impaired kidney function is more common in light chain multiple myeloma than other types of multiple myeloma. This can result in poorer outcomes.
The article notes that bortezomib is an important part of the treatment for managing kidney failure in multiple myeloma.
In a long-term
If a person has amyloidosis affecting
Multiple myeloma is a cancer of the plasma cells found in bone marrow. Light chain myeloma is a subtype of multiple myeloma.
Cancerous plasma cells, or myeloma cells, produce immunoglobulins. These immunoglobulins consist of heavy and light chain proteins.
A person has light chain myeloma if the immunoglobulins from myeloma cells only contain light chain proteins. Light chain myeloma can increase the risk of kidney failure and may result in poorer outlooks than other types of multiple myeloma.
Early diagnosis and treatment, and a treatment regimen with the drug bortezomib help improve a person’s outlook.