Hematologist
CION Cancer Clinics
Large granular lymphocytic leukaemia, explained | CION Cancer Clinics
LGL leukaemia is a rare, usually slow-growing blood cancer in which one family of large white cells builds up. Many people need no treatment at first and are followed with regular blood counts. When treatment is needed, it is usually tablets that calm the immune system, not intensive chemotherapy. This page explains the types, the tests that confirm it, and when treatment starts. At CION Cancer Clinics, every leukaemia, MDS and MPN case is reviewed by our haematologist and discussed at a tumour board before a plan is agreed.
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Medically reviewed by Dr. Basudev PokhrelConsultant Haematologist · last reviewed September 2026, next review due September 2027
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The short answer
What is LGL leukaemia?
Large granular lymphocytic (LGL) leukaemia is a rare, usually slow-growing blood cancer in which one family of large white cells, called large granular lymphocytes, grows in excess. Many people need no treatment when it is found, and some never need any.
Where the name comes from
Lymphocytes are white blood cells that fight infection. Some are larger than usual and carry small grains, or granules, inside them. In LGL leukaemia, a single family of these cells, all copies of one original cell, builds up in the blood, the bone marrow and often the spleen.
Why it causes trouble
The extra cells do not usually cause harm by their number alone. The problem is that they can attack and suppress the healthy cells the marrow makes. The most common result is a low neutrophil count, the white cells that fight bacteria. This leads to repeated infections, mouth ulcers or skin infections. Some people develop low haemoglobin, with tiredness and breathlessness.
Why it is often found by chance
A large share of people have no symptoms at all. The first sign is often a blood report ordered for something else, showing a raised lymphocyte count or a low neutrophil count that does not go away on repeat testing.
The types
Is every LGL leukaemia the same?
No. The report will say which kind of cell is involved, and that changes how closely it is watched.
T-cell LGL leukaemia
The most common form. It usually grows very slowly over years. Many people are simply monitored with blood counts.
Often seen with
- A low neutrophil count
- Rheumatoid arthritis
- An enlarged spleen
Chronic NK-cell disorder
Here the cells are natural killer (NK) cells, a close relative. It also tends to be slow and may cause few or no symptoms. Some reports call it a lymphoproliferative disorder rather than a leukaemia.
Aggressive NK-cell leukaemia
A very different, rare and fast illness, with fever, a large liver and spleen, and quickly falling counts. It is linked to the Epstein-Barr virus and needs urgent specialist care.
It is not the same illness as the slow forms, even though the names sound alike.Not sure whether this applies to you?
Ask an oncologistGetting a diagnosis
Which tests confirm it?
Repeat blood counts and a smear
A raised count of large granular lymphocytes on the blood smear is the first clue. Your doctor will want it confirmed on more than one occasion, because infections and some medicines can raise these cells for a while.
Flow cytometry
This test reads the markers on the surface of the cells. It shows whether the cells are T cells or NK cells, and whether they look abnormal.
A clonality test
A gene test, often called a T-cell receptor rearrangement, checks whether the cells all come from one parent cell. That is what separates a leukaemia from a harmless reaction.
STAT3 and marrow tests
A STAT3 gene change is found in many cases and supports the diagnosis. A bone marrow biopsy may be done when counts are very low or the picture is unclear.
Side by side
When is it watched, and when is it treated?
Usually watched
Usually treated
No symptoms and no repeated infections
Repeated or serious infections from a low neutrophil count
Neutrophil count low but holding steady
Neutrophil count very low, even without infections yet
Haemoglobin normal or only mildly low
Haemoglobin low enough to need transfusions
Joint symptoms controlled by your rheumatologist
Autoimmune problems made worse by the leukaemia cells
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If treatment is needed
What does treatment involve?
Treatment for the slow forms is usually a medicine that calms the immune system, taken as tablets for months. It is not the intensive chemotherapy people fear when they hear the word leukaemia.
The medicines you may hear about
Methotrexate, cyclophosphamide and ciclosporin are the usual choices. They quieten the abnormal cells so the marrow can make neutrophils and red cells again. It often takes a few months to see whether a medicine is working, so your team will judge it on repeat counts rather than on a single report.
Who a treatment does not suit
Some of these medicines are unsuitable in pregnancy, in people with certain kidney or liver problems, or with some other medicines. Your haematologist will check your kidney and liver tests and your full medicine list first. Never start, stop or change these tablets on your own, even if you feel well.
Where CION fits
CION's haematology team reviews your reports, presents your case at a tumour board and works with your rheumatologist if you have one. Specialised tests such as the clonality and STAT3 tests are coordinated with qualified laboratories.
Growth factor injections and steroids may be used alongside for a short time. Your team decides this.Commonly believed
What do families often get wrong about it?
"Leukaemia means it is spreading fast."
The common forms of LGL leukaemia usually change very slowly over years. The fast, aggressive NK form is a separate and much rarer illness. Ask your haematologist which one is on your report.
"If they are only watching, they are missing something."
Watching is a deliberate choice when counts are steady and there are no infections. Treatment carries its own side effects, so it is started when the benefit outweighs them.
"Mouth ulcers and boils are just heat in the body."
With a low neutrophil count, repeated ulcers, skin infections or fevers may be the illness showing itself. Tell your haematologist about each one rather than treating them at home.
"Arthritis and a blood cancer cannot be connected."
They often are. Rheumatoid arthritis is common in people with T-cell LGL leukaemia, so both doctors need to see each other's reports.
Being straight with you
What can this page not tell you?
This page cannot tell you whether your raised lymphocytes are LGL leukaemia. A high count on one report can follow a viral infection, a recent vaccine, some medicines or a transplant. Only repeat tests and a clonality test settle it.
It cannot tell you your outlook
Your own outlook depends on the type, how low your counts go, how you respond to treatment and your other health problems. Ask your haematologist to explain what your results mean for you. Online figures describe other groups of people.
What to bring to your appointment
Bring every blood report you have, in date order, including old ones. A trend over time tells the haematologist far more than a single number. Bring your medicine list and any rheumatology notes too.
Questions we are asked
Common questions about LGL leukaemia
Is LGL leukaemia a cancer?
It is classed as a blood cancer, because the extra cells come from one abnormal parent cell. But the common forms behave very differently from what most families picture. They grow slowly, often cause few symptoms and are mostly managed with regular blood tests or gentle immune-calming tablets.
My mother's report says raised lymphocytes. Is it LGL leukaemia?
Not necessarily. A raised lymphocyte count is common after viral infections and for several other reasons. LGL leukaemia is rare. If the raised count persists on repeat testing, or comes with a low neutrophil count, a haematologist can decide whether flow cytometry and a clonality test are needed.
Will she need chemotherapy in hospital?
For the slow forms, usually not. When treatment is needed it is most often a tablet taken at home, with regular blood tests to check the counts, the kidneys and the liver. Hospital care is mainly for serious infections or for the rare aggressive NK form.
Why do infections keep coming back?
The leukaemia cells can suppress the neutrophils, the white cells that fight bacteria. With too few of them, skin, mouth and chest infections happen more often and can become serious quickly. A fever with a low neutrophil count needs a doctor the same day.
What should we do if a fever starts?
If the neutrophil count is known to be low, treat a fever or shivering as an emergency. Go to the nearest emergency department the same day or call 108, and show them the latest blood report. Do not wait to see if it settles, and do not take leftover antibiotics first.
How often will blood tests be needed?
That depends on how stable the counts are. Soon after diagnosis or when starting a medicine, tests are frequent. Once things are steady, they are usually spaced further apart. Your haematologist will set the interval and tell you which changes should bring you in sooner.
Can LGL leukaemia turn into a faster leukaemia?
The common T-cell form very rarely changes into an aggressive illness. Follow-up is still important because counts can fall and infections can appear years later. Any new fevers, weight loss or night sweats should be reported to your haematologist.
Are the tests and treatment covered by schemes?
Blood cancer care is often covered by Aarogyasri, PM-JAY, CGHS, ECHS, EHS and cashless insurance, though specialised laboratory tests are not always included. Scheme rules change, so ask the helpline to check your current cover before tests are sent.
Your Haematologist
Meet CION's haematologist. One specialist for your blood report and your plan.
Dr. Basudev Pokhrel reviews blood counts, transfusion needs and blood disorders, and works with the CION tumour board on blood cancers.
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Sources
- Leukemia & Lymphoma Society — Leukemia
- National Cancer Institute — Leukemia - Patient Version
- Cancer Research UK — Leukaemia
- National Health Mission — National Health Mission
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
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Raised lymphocytes or a low neutrophil count?
Share your blood reports with us. CION's haematology team will tell you what they suggest and which tests come next. One helpline serves every CION centre.