neutrophils and lymphocytes are the type of white blood cells that play a key role in protecting the body from infection and more.
White blood cells are a key component of the body’s response to stress and coordinate a process called inflammation.
Counting the number of neutrophils and dividing by the number of lymphocytes, a ratio called the “neutrophil-to-lymphocyte ratio” (NLR), is a measure of inflammation in the body.
Neutrophils and Lymphocytes in Inflammation
Neutrophils, the first responders to inflammation, quickly arrive on the scene and begin to play a role in a process called innate immunity.
Lymphocytes are slower but still important in responding to inflammation and tend to arrive after neutrophils as part of an adaptive immune response.
The NLR’s work is based on the knowledge that increased levels of stress hormones produced by the body will drive higher levels of neutrophils and lower levels of lymphocytes.
Therefore, this simple ratio can serve as a marker for the level of stress the body experiences during an acute illness.
Changes in neutrophil and lymphocyte levels correlate with the severity of a variety of diseases, including infection, cancer, even major cardiovascular events.
How do you measure NLR?
Measuring white blood cell levels is done using a common blood test called a complete blood count (CBC), which identifies specific types of white blood cells circulating in the blood.
When performing a complete blood count, the instrument used can identify and count neutrophils and lymphocytes.
Armed with this information, healthcare providers can calculate NLR ratios and gain insight into the body’s inflammatory state. A normal NLR is usually between 1 and 4, although this value can vary from person to person.
NLR levels above 6 are considered indicators of severe inflammation. In severe disease, the NLR may be as high as 100.
What is the risk of elevated NLR?
During stress episodes, such as when the body is responding to an infection, the NLR can rise abnormally and climb to levels as high as 100. Therefore, NLR is best viewed as a marker of inflammation that can help doctors determine the severity of ongoing stress in the body.
For example, NLR is associated with severe infections with COVID-19 and other infectious diseases. In other studies, elevated NLR was able to identify individuals likely to have more severe cardiovascular and respiratory disease.
Several studies have also investigated the role of NLR in the prognosis of cancer patients receiving chemotherapy. NLR is a predictor of adverse outcomes such as weight loss Cachexia (weight loss and muscle wasting) people undergoing chemotherapy.
NLR may be most useful for predicting the severity of infection. Research suggests that the use of NLRs in hospital emergency departments may help identify and more rapidly treat bloodstream infections known as bacteremia.
At the same time, NLR can be used to aid in the diagnosis of appendicitis (inflammation of the appendix, a small tubular pouch that extends from the large intestine on the right side of the abdomen).
Elevated NLR has been shown to correspond to the severity of appendicitis and may help determine the need for surgery.
It is important to note that NLR is only a measure and must be fully assessed in the context of a specific disease before any decision can be made.
There are many potential causes of elevated NLR. As such, NLR is most often used as a way to assess disease severity and how the body responds to infection.
Conditions with elevated NLR include:
- Sepsis (potentially life-threatening systemic inflammatory response to infection)
- Bacteremia (bloodstream infection)
- Septic shock (low blood pressure due to sepsis)
- Pancreatitis (inflammation of the pancreas)
- Appendicitis (inflammation of the appendix)
- Inflammatory diseases, such as Crohn’s disease and ulcerative colitis (type of inflammatory bowel disease)
- Autoimmune diseases such as rheumatoid arthritis
- Asthma (a chronic lung disease that causes difficulty breathing) and allergies (immune responses to normally harmless substances)
Interpreting high neutrophils with low lymphocytes
The neutrophil-to-lymphocyte ratio is a relatively new measure of inflammation in the body that is still gaining acceptance.
Growing clinical evidence underscores the utility of this measure, however, it may not always be applicable to all diseases.
To properly assess the body’s response to acute illness, NLR needs to be interpreted in the context of other laboratory and blood tests. For this reason, measuring NLR should be done with the help of a healthcare provider who can help interpret the results as well as other measures.
In some cases, NLR may not be accurately measured. For example, certain cancers, such as leukemia, may affect NLR measurements.
In addition, certain treatments, such as chemotherapy or bone marrow or stem cell transplantation, can also alter the NLR and limit its predictive power.
High neutrophils and low lymphocytes together represent elevated NLR ratios. Elevations can be caused by many different conditions and can be an indicator of a serious infection, inflammatory disease or cancer.
High levels of neutrophils can indicate a serious infection or stress in the body. Low levels of lymphocytes may also reflect severe stress and the release of stress hormones.
If you see high neutrophils and low lymphocytes in your lab report, discuss this finding with your healthcare professional.
While it may indicate inflammation, it needs to be interpreted taking into account your overall health, symptoms, and other diagnoses. Like any lab test, it’s just a tool for diagnosing disease.
Frequently Asked Questions
- What causes high neutrophils and low lymphocytes?
When the body is under severe physiological stress, levels of neutrophils may be high and lymphocytes may be low. The inflammation seen in many different conditions can produce this result.
- What is the reason for the high NLR?
The release of natural stress hormones contained in the body regulates the levels of neutrophils and lymphocytes in the body. These hormones help the body initiate an inflammatory response to respond to and fight infection, cancer and other diseases.
- What does it mean when your lymphocytes are low?
Lymphocytes are a specific group of white blood cells that play a vital role in fighting infection, creating immunity and controlling abnormal cells in our body. When lymphocyte levels are low, this is a sign that the body may be under severe stress.
- Does high neutrophil count predict cancer?
No, high neutrophils are not a reliable indicator of cancer. Diagnosing cancer requires a combination of blood tests, imaging, and organ tissue tests.