Multiple myeloma

Multiple myeloma (also called myeloma) is a cancer of the plasma cells, which are a type of white blood cell made in the bone marrow. About 370 people are diagnosed with myeloma in Ireland every year.* There are several treatments that can slow down and control multiple myeloma very well. 

When you have myeloma, abnormal plasma cells are made in your bone marrow. These abnormal cells are called myeloma cells. 

• Healthy plasma cells. Produce antibodies (immunoglobulins) to fight infection and keep you healthy. 
• Abnormal plasma cells (myeloma cells). Usually produce a lot of abnormal antibodies called paraproteins (or M proteins). Paraproteins can reduce the amount of normal antibodies being made. This affects your ability to fight infection and build immunity, which can result in more infections. 
• The myeloma cells build up in the bone marrow, leaving less room for normal plasma cells to develop. This may cause complications and symptoms, such as bone pain, fractures, infections, reduced kidney function and reduced numbers of red and white blood cells.

Multiple myeloma can be a difficult disease to understand. Always ask your doctor or nurse if you don't understand something. It's important to remember the following:

How multiple myeloma might affect you and how effective treatment is can depend on many things, including the type of myeloma you have.

Understanding immunoglobulins

What is an immunoglobulin? 

Immunoglobulin is another word for antibody. Antibodies are proteins that protect your body from infection and disease. Your body produces 5 main types of immunoglobulins to help you to fight infection. Each type of immunoglobulin has a different function in fighting disease. 

Light chains and heavy chains 

Immunoglobulins (antibodies) are made up of 2 types of proteins – light chains and heavy chains. 

• Heavy chains: Each immunoglobulin is identified by a letter – A, D, E, G or M. These letters refer to the type of heavy chains in the immunoglobulins. The 5 types of immunoglobulin are often described as IgA, IgD, IgE, IgG and IgM. 
• Light chain: The immunoglobulins also have 2 light chain portions, which are called kappa (K) or lambda (L). 

Abnormal immunoglobulins and myeloma 

With myeloma you produce an abnormal type of immunoglobulin. There are different types of myeloma, depending on the type of abnormal immunoglobulin (Ig) made by the myeloma cell. The most common ones are IgG and IgA. The others are quite rare.

The cause of multiple myeloma is unknown. But there are certain things called risk factors that can increase your chance of developing the disease. These include:          

• Age: Multiple myeloma happens mostly in people aged over 50.
• Gender: It is more common in men than women.
• Race: It is more common in black people than in white or Asian people.
• Exposure to gases and chemicals: Lifelong exposure to chemicals can affect your immune system and increase your risk. These include petrol, oil, benzene, certain pesticides, dioxins, paints, rubber and hair dyes. 
• Plasma cell conditions: People with monoclonal gammopathy of uncertain significance (MGUS) or smouldering myeloma or amyloidosis have a much higher risk of myeloma.  
• Other medical conditions: These include autoimmune illnesses, pernicious anaemia, ankylosing spondylitis and other illnesses that affect your immune system.
• Exposure to viruses: These include HIV, hepatitis, herpes virus 8 and simian virus 40.
• Exposure to radiation: This includes exposure to high doses of radiation in industry or nuclear accidents or to previous radiotherapy.
• Family history: If your parent, brother or sister had multiple myeloma your risk is increased but the risk is low. 

Medical content updated from our 'Understanding multiple myeloma' booklet (2024), reviewed by John Quinn, Consultant Haematologist, Geraldine Walpole, Advanced Nurse Practitioner in Haematology and Aileen Emery, Daffodil Centre Nurse.