Multiple myeloma and AL amyloidosis are conditions linked to plasma cells in the bone marrow.

Multiple myeloma (MM) is a cancer affecting the plasma cells, which are mostly in the bone marrow. MM occurs if plasma cells turn cancerous and multiply out of control.

Amyloidosis develops from a bone marrow disorder. It occurs when an abnormal protein, called amyloid, builds up and forms deposits in the body. Amyloidosis is closely linked to MM.

Amyloid light chain (AL) amyloidosis is the most common type of amyloidosis in the United States. Doctors may also refer to AL amyloidosis as primary amyloidosis.

This article looks at the causes, diagnosis, treatments, and outlook for people with MM with AL amyloidosis.

A laboratory assistant using a microscope to test for multiple myeloma and AL amyloidosis -2.Share on Pinterest
romaset/Getty Images

MM occurs when cancerous plasma cells grow out of control. The plasma cells produce an abnormal antibody called a monoclonal protein.

The overgrowth of plasma cells can crowd out or disrupt the function of other cells. This can lead to:

AL amyloidosis is a buildup of amyloid protein in the body. Deposits of amyloid protein form more quickly than the body can break them down.

Plasma cells produce antibodies, which form part of the immune system and help fight off infections.

“Immunoglobin” is the term for a group of proteins that work as antibodies and consist of four protein chains. Two of these chains are light chains, and two are heavy chains.

In AL amyloidosis, there is an abnormal forming of the light chain proteins. This process is called misfolding and causes amyloid to form.

The amyloid deposits collect in and around organs, tissues, and nerves throughout the body, which can then cause damage and affect how well an organ can function.

MM and AL amyloidosis can occur together. According to a 2021 case report, around 10–15% of people with MM also have AL amyloidosis.

Learn more about amyloidosis.

Researchers are unclear on the exact causes of MM, but it may link to certain DNA changes that lead to plasma cells becoming cancerous. Genetic mutations and changes in chromosomes may result in MM.

AL amyloidosis usually occurs due to a plasma cell disorder or abnormality.

MM can cause AL amyloidosis, although AL amyloidosis that links to MM is rare.

Who does AL amyloidosis affect?

According to a 2022 research review:

  • The risk of developing AL amyloidosis increases each decade after 40 years, with the median age of diagnosis at 64 years.
  • Fewer than 5% of people with AL amyloidosis are under age 40.
  • AL amyloidosis is more common in males than females.
Was this helpful?

Read about the pathophysiology of MM.

Doctors use many of the same tests to diagnose MM and AL amyloidosis but with some differences.

MM diagnosis

According to the American Cancer Society, doctors may use the following tests to diagnose MM:

  • complete blood count
  • blood chemistry test, which can show kidney function, levels of calcium in the blood, and levels of a type of protein called albumin in the blood
  • quantitative immunoglobulins, which measure levels of different antibodies in the blood
  • urine tests, such as electrophoresis, to check for monoclonal protein
  • serum free light chains, a blood test that measures levels of light chains in the blood and can help detect MM and AL amyloidosis
  • biopsy, which may include bone marrow biopsy to check for myeloma cells, or to remove a tissue sample from a tumor or lymph node to check for cancer
  • imaging scans, such as X-rays, CT scans, or MRI scans, to check for bone damage or abnormalities in bone marrow
  • PET scan to help identify cancer cells in the body

Read more about MM blood tests.

AL amyloidosis diagnosis

Tests to diagnose AL amyloidosis may include:

  • biopsy, to check for amyloid protein, which may take fat from the abdomen or tissue from the bone marrow
    • In rare cases, doctors may take a biopsy from an organ if they suspect amyloid may be causing heart or kidney problems.
  • serum free light chains
  • electrophoresis
  • echocardiogram to detect any amyloid in the heart

Doctors diagnose AL amyloidosis if all of the following criteria are present:

  • symptoms and signs of amyloidosis
  • a biopsy finds amyloid in any tissue of the body, such as bone marrow, fat, or an organ
  • the amyloid protein tests positive as a light chain protein rather than a heavy chain
  • tests show abnormal plasma cells in bone marrow or high levels of monoclonal protein in the blood or urine

This section outlines the treatment doctors may recommend for MM and AL amyloidosis.

MM treatment

Treatment for MM may include:

AL amyloidosis treatment

Treatment for AL amyloidosis depends on the organs and tissues the condition affects and the severity of the condition.

Treatment aims to treat organ damage, manage symptoms, and slow or prevent the production of amyloid. Treatment may include:

  • treating any heart or kidney problems
  • treating any gastrointestinal issues, which may include medications
  • using a medication called DARZALEX Faspro, which is a combination of daratumumab and hyaluronidase-fihj
  • a stem cell transplant if the person is eligible
  • chemotherapy drugs, such as melphalan
  • proteasome inhibitors, such as bortezomib
  • immunomodulators, such as thalidomide

People may also be eligible to participate in clinical trials, which often use newer, investigational drugs.

According to a 2021 study, AL amyloidosis may worsen the outlook for people with MM or smoldering MM, a subtype of MM that causes no symptoms. This is due to how AL amyloidosis affects vital organs, particularly the heart.

AL amyloidosis may have a greater impact on the outlook for people with smoldering MM than symptomatic MM. Treatment with bortezomib may help improve outcomes.

A combination of drugs may be more effective than single-drug treatment and help provide the best possible outlook. Many newer drugs are effective against the plasma cells that cause AL amyloidosis.

Read about the outlook for people with MM.

MM is a cancer of plasma cells. AL amyloidosis occurs due to a plasma cell disorder, resulting in a buildup of amyloid protein in and around tissues and organs.

Around 10–15% of people with MM may also have AL amyloidosis.

Treatment for both conditions may include combination drug therapies and stem cell transplants.