Ask the Nurse: Light chain, oligosecretory and non-secretory myeloma

Most myeloma patients will hear about paraproteins at the time of diagnosis. These abnormal proteins, found in the blood, are one of the key indicators of myeloma and play an important role during both diagnosis and ongoing monitoring. However, some patients have less common types of myeloma where paraproteins are made in much smaller amounts (oligosecretory myeloma), not at all (non-secretory myeloma), or only the light chain part of the paraprotein is produced (light chain myeloma).

In this month’s blog we answer your questions about these types of myeloma, what they mean and how they might affect your care.

What are paraproteins and light chains?

Myeloma is a cancer that affects plasma cells, a type of white blood cell found in the bone marrow. Healthy plasma cells make antibodies (immunoglobulins) to help fight infections. These antibodies are made up of two parts: heavy chains and light chains as shown in Figure 1.

Figure 1

• Heavy chains: There are five types – IgA, IgD, IgE, IgG and IgM. These letters refer to the type of heavy chains in the antibody.
• Light chain: There are two types – kappa (κ) and lambda (λ). In people without myeloma, there is usually a balance between the two (called the kappa to lambda ratio, or the free light chain ratio).

In people with myeloma, abnormal plasma cells (myeloma cells) produce large amounts of one type of antibody. This is known as paraprotein (or M-protein) and has no useful function.

The abnormal plasma cells in myeloma also produce either excess kappa or lambda light chains, disrupting the balance of the two and altering the kappa to lambda ratio. These excess light chains, when found circulating freely in the blood or excreted in urine, are referred to as free light chains.

Measuring paraproteins and free light chains is a key part of diagnosing and monitoring myeloma. You can read more in our Ask the Nurse: Paraproteins and free light chains blog.

What is light chain myeloma?

In around 1 in 5 people with myeloma, the abnormal plasma cells produce only the light chain part of the antibody.

These free light chains (also known as Bence Jones protein) are smaller than complete paraproteins, allowing them pass into the kidneys. Sometimes they will build up in the tiny tubes inside the kidneys, leading to inflammation or damage. If you have light chain myeloma, your healthcare team will monitor your kidney function closely.

You may be told you have kappa or lambda light chain myeloma depending on which type of light chain the abnormal plasma cells are making in excess.

What is oligosecretory and non-secretory myeloma?

These are much rarer forms of myeloma, affecting only around 1 in 100 patients.

• Oligosecretory myeloma means the myeloma cells are producing very small amounts of paraprotein or light chains – too little to show up easily on standard blood or urine tests.
• Non-secretory myeloma means that myeloma cells are present but no detectable paraprotein or light chains are found in the blood or urine, even with sensitive testing.

What are the symptoms of these types of myeloma?

The symptoms of light chain, oligosecretory, and non-secretory myeloma are usually the same as in standard myeloma, including fatigue, bone pain, frequent infections, or kidney problems. Read more about the symptoms & complications of myeloma on our website or in our Myeloma – An Introduction Infoguide.

Having a rarer type of myeloma may feel especially confusing or isolating at times. You can approach your healthcare team if you have any questions about your diagnosis or care. You might find that talking to your friends and family about your experiences may help you feel less alone. Our Myeloma Information Specialists can also offer support – get in touch on 0800 980 3332 (UK) or use our Ask the Nurse email service.

What tests are used to diagnose and monitor these types of myeloma?

Light chain, oligosecretory and non-secretory myeloma can be more challenging to diagnose and monitor because there aren’t always detectable changes in the blood.

However, in addition to monitoring your symptoms closely, there are specific tests, or combinations of tests, that can be helpful:

• Serum free light chain test (sFLC) measures the amount of free light chains in the blood and can compare the ratio of kappa and lambda. It is useful for diagnosing and monitoring light chain and oligosecretory myeloma.
• Urine tests can be used to look for free light chains (Bence Jones protein) in the urine.
• Advanced imaging techniques such as MRI or PET-CT scans can be important to look for signs of bone damage or disease progression.
• Bone marrow biopsies may be necessary to directly examine the bone marrow for myeloma cells but is typically only used if other tests are not providing enough information for your healthcare team.

For more information you can read the Tests and investigations in myeloma Infoguide.

What treatments are available?

Treatment for these types of myeloma is usually the same as for standard myeloma. Each treatment plan is personalised and depends on a number of factors such as your symptoms, whether you have specific complications caused by your myeloma, how well the myeloma responds to treatment and your overall health.

Find out about the types of treatments you may receive on the Treating myeloma section on our website.

Are there different risks with these types of myeloma?

There are a few specific considerations in these types of myeloma:

Delayed diagnosis

Sometimes, some of these types of myeloma are harder to spot early, especially if symptoms are vague and blood tests initially appear normal. This is why imaging and biopsies are so important if symptoms suggest myeloma but blood and urine test results don’t show typical markers.

Kidney damage

In light chain myeloma, the free light chains are more likely to build up and cause damage to the kidneys. Early detection and treatment are key to protecting kidney function.

Challenges to monitoring the myeloma

It is important for everybody living with myeloma to have regular monitoring to manage the myeloma and treatment. In types of myeloma where blood tests don’t detect disease activity accurately, more frequent imaging or biopsies can help. This can be more invasive, but it supports your healthcare team in monitoring the myeloma effectively.

Although light chain, oligosecretory and non-secretory myeloma can create different challenges for diagnosis and management, it’s important to remember that effective treatments are available, and your healthcare team will tailor monitoring to suit your individual needs. Additionally, ongoing research is focused on developing more sensitive and reliable methods for monitoring these types of myeloma.

Don’t hesitate to ask your healthcare team for further information on anything you may be unsure of. Our Infopack for Living well with myeloma offers tips and information that can help you navigate the emotional and practical challenges any diagnosis of myeloma may bring.

If you have any further questions or need support, contact us through the Myeloma UK Infoline at 0800 980 3332 (UK) or use our Ask the Nurse email service.