This type of lymphoma happens when something goes wrong with the development of certain white blood cells (usually B lymphocytes). This affects your immune system, which means you're more likely to get infections. It can cause your lymph nodes (glands) to swell.

The term low-grade non Hodgkin lymphoma (low-grade NHL) can be used to describe a number of different types of slow-growing lymphoma, including follicular lymphoma, Waldenström macroglobulinaemia (WM), mantle cell lymphoma and marginal zone lymphoma.

While the different types of low-grade NHL can cause similar symptoms and may be treated in similar ways, you should speak to your healthcare team about which parts of this information are relevant to you. This section is mainly about follicular lymphoma, which is the most common type of low-grade NHL.

In around 30% of people, low-grade NHL transforms into high-grade non-Hodgkin lymphoma.

> Download our booklet on low-grade non-Hodgkin lymphoma

What is low-grade non-Hodgkin lymphoma (NHL)?

Non-Hodgkin lymphoma (NHL) is a blood cancer that affects a type of white blood cells called lymphocytes.

There are two main types of NHL, which are grouped depending on how quickly the cancer grows and spreads. The two types are high-grade lymphoma, which develops quickly; and low-grade lymphoma, which develops more slowly.

If you have low-grade NHL, your cancer will also be defined by your symptoms and by how much lymphoma there is in your body. This is known as the ‘stage’ of the cancer, which will determine the treatment you’ll be offered.

Lymphoma is a cancer of the lymphatic system. Non-Hodgkin lymphoma is a type of lymphoma that usually affects B cells. There are different types of non-Hodgkin lymphoma, which are grouped depending on how fast the lymphoma grows and spreads.


When you have lymphoma some of your lymphocytes don’t work properly. Sometimes they aren’t developed fully (they’re immature), they divide in an abnormal way, or don’t die when they should. These abnormal lymphocytes can build up in your lymph nodes, causing them to swell and form a lump. Swollen lymph nodes can be in a place where they can be easily felt (such as your armpits, neck or groin) or they can be deep inside your chest or abdomen. Lymphoma can occur anywhere in the body where lymphocytes collect.

The abnormal lymphocytes can affect how your immune system works, which can sometimes mean you’re more likely to get infections.

Non-Hodgkin lymphoma (NHL)

NHL is divided into two main groups:

  • Low-grade lymphoma: this usually develops slowly and sometimes doesn’t require treatment at the time of diagnosis.
  • High-grade lymphoma: this usually develops more quickly and usually requires more urgent treatment.

These pages mainly talk about the most common type of low-grade NHL called follicular lymphoma. This is a type of low-grade NHL that affects B cells. There are some other types of low-grade NHL that behave differently, and are treated differently, to follicular lymphoma:

As each individual case is so different, particularly in non-Hodgkin lymphoma, your consultant is the best person to ask about your type of lymphoma and your treatment. 

Watch Dr Robert Marcus, Consultant Haematologist, King's College Hospital, London, explain low-grade NHL.

Your immune and lymphatic system

Your lymphatic system

Lymphoma is a disease that affects your lymphatic system. The different types of lymphoma depend on what types of cells are affected.

The lymphatic system is part of your body’s natural defence against infection, which is known as the immune system. Within your lymphatic system there’s a network of thin tubes called lymph vessels that run around your body.

The vessels collect fluid called lymph and return it to your blood. Lymph bathes all the cells in your body. It contains lots of lymphocytes (a type of white blood cell that fights infection), which carry nutrients and remove bacteria from infected areas.

Along the lymph vessels are small lumps of tissue called lymph nodes or lymph glands. There are many of these in your body. It may be possible for you to feel normal lymph nodes in the neck and groin, particularly if you’re slim.

If you get an infection when you’re healthy, these can swell and become tender, which people may refer to as swollen glands. As lymphocytes pass through the lymph nodes, they are changed and activated to fight certain types of infection. Your spleen is also part of your lymphatic system. It can do some of the same work as the lymph nodes. It also filters out old or damaged cells from the blood stream and helps to fight infection.

Your immune system

Your immune system is a network of cells, tissues and organs that protect your body against infection. It’s able to react quickly to infections it’s seen before, and lymphocytes play an important role in this. There are lots of different kinds of lymphocyte, including ones called T cells and B cells. These can be affected when you have lymphoma, which can increase the risk of infections. Your healthcare team can let you know about the ways to reduce your risk.

Information and resources on NHL

As the information isn't produced by Bloodwise, we can't guarantee the content of these pages. We've marked information which is more suitable for healthcare professionals.

Blood and bone marrow

Blood components from the NHS Blood and Transplant

The immune system

What is immunology? from the British Society for Immunology


Non-Hodgkin lymphoma incidence statistics from Cancer Research UK

QuickStats on incidence of blood cancers from the Haematological Malignancy Research Network


Non-Hodgkin lymphoma – general discussion of NHL on [for healthcare professionals]

Non-Hodgkin lymphoma risks and causes from Cancer Research UK

Signs and symptoms

Non-Hodgkin lymphoma from Cancer Research UK

Tests and investigations

Lab tests online – Department of Health approved website with details on tests and investigations


Types of treatment for non-Hodgkin lymphoma from Cancer Research UK


Follow up for non-Hodgkin lymphoma from Cancer Research UK

What causes low-grade NHL?

When you’re diagnosed with any cancer, one of the first things you might think is: ‘why me?’

You’re not alone. About 3,000 people are diagnosed with low-grade NHL every year in the UK.

In most cases, we can’t say what causes low-grade NHL. However, there are some factors that could make you more likely to develop low-grade NHL.

How common is NHL?

Around 10,000 people are diagnosed with a type of non-Hodgkin lymphoma every year in the UK.

About one-third of people diagnosed with NHL will get the low-grade type of the disease. The majority of those with low-grade NHL have a type called follicular lymphoma.


You can get low-grade NHL at any age, but it mainly affects older people. The average age of someone diagnosed with NHL is about 65. It’s uncommon for people under 40 to get low-grade NHL.

Low-grade NHL is very rare in children.


Men are slightly more likely than women to develop low-grade NHL; we don’t know why.

Family history

In most cases, low-grade NHL doesn’t run in families. However, rarely, in some families there are more cases of low-grade NHL than would be expected to occur just by chance.

If you feel this is the case for your family, please do discuss it with your doctor.


You might have a higher risk of getting NHL if you’ve had some viral infections, including the HIV virus and human T-cell leukaemia/lymphoma virus (HTLV-1). The HTLV-1 virus most commonly occurs in patients of Japanese or Afro-Caribbean origin.

The Epstein-Barr virus (EBV), which causes glandular fever, can sometimes lead to NHL. This virus is common, but only a very small number of people who get the virus go on to develop NHL and this is more usually related to more aggressive types of lymphoma.

It’s important to remember that although these viruses can be passed from person to person, you can’t catch lymphoma from someone else. And only a tiny number of people will ever then go on to develop NHL; a lot of things have to happen after you get the virus, for it to turn into NHL.

Watch Dr Robert Marcus, Consultant Haematologist, King's College Hospital, London, explain what causes and who gets low-grade NHL.

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