Lymphopenia, which indicates lower levels of lymphocytes in the blood, has been tied to a higher risk of future illness and death, a new study found.
In the new study, published in the Canadian Medical Association Journal (CMAJ), a team of researchers aimed to identify the connection between lymphopenia and all-cause and cause-specific mortality in the general population. They found that low levels of lymphocyte blood cells could signal an increased risk of developing a future illness, and a 60-percent increase in death from any cause.
3d rendered illustration of the human blood cells and lymphocytes. Image Credit: Sebastian Kaulitzki / Shutterstock
Role of lymphocytes in the body
Lymphocytes are part of the white blood cells, which are responsible for warding off pathogens and other foreign bodies that can cause harm or illness. Specifically, lymphocytes fight off infections by recognizing antigens, producing antibodies, and destroying harmful cells that could cause damage to the body.
High lymphocyte levels may indicate an ongoing infection, while low levels have been typically linked to infectious diseases, like human immunodeficiency virus (HIV), tuberculosis, AIDS, typhoid fever, and viral hepatitis. In some cases, blood cancer like Hodgkin’s disease, aplastic anemia, autoimmune disease, and cancer treatment can cause decreased lymphocyte levels.
Low lymphocyte count is often detected during routine blood tests. When the doctor sees the low reading, he or she refers the patient for further investigation since lymphopenia is a known predictor of future health problems.
To land to their findings, the researchers enrolled more than 100,000 people of Danish descent between the ages of 20 and 100, who were part of the Copenhagen General Population Study from 2003 to 2015. After the analysis of the data, they found that an incidental finding o a low lymphocyte count was tied to about a 1.6-fold increase in the risk of death from any cause, and a 1.5 to 2.8-fold increase in the risk of dying from cancer, respiratory disease, cardiovascular disease, infections, and other causes.
“We found that lymphopenia was associated with an increased risk of all-cause and cause-specific mortality,” the researchers concluded in the study.
In the duration of the study, 10,372 people died. The researchers also noted that increasing age was linked to decreasing lymphocyte count.
"Our study showed that participants with lymphopenia were at high risk of dying from any cause, regardless of any other risk factor for all-cause mortality including age," Dr. Stig Bojesen and coauthors wrote on the paper.
The researchers believe that the connection between low lymphocytes and death may be due to the reduced ability of the immune system to fight off potentially life-threatening diseases and there’s reduced immune surveillance, reducing the capacity of the body to survive an illness.
In some cases, patients with low lymphocytes are frail, which predisposes them to illness and death.
The team hopes that the findings of the study may help doctors detect people who are at risk. With surveillance and preventive measures like lifestyle changes, they may improve the quality of life of these patients.
Further, the researchers said further research is needed among other races since the study involved participants who were white and of Danish descent.
What are the signs and symptoms of lymphopenia?
Lymphopenia or low lymphocyte count indicates many health conditions, such as chronic infections, cancers, and autoimmune diseases.
First off, it’s important to know the types of lymphocytes to determine which pathogen is responsible for the infection. B cells are the type of lymphocytes that make antibodies and signal proteins to initiate an attack against invading viruses, bacteria, and toxins. T cells are the ones that look for and kill the cells that are infected or are cancerous. Lastly, natural killer (NK) cells contain compounds that can destroy or kill cancer tumor cells or those which were invaded by a virus.
There are usually no signs and symptoms of lymphopenia, and the condition is usually discovered when a person gets tested for conditions like HIV, AIDS, or lupus, or through routine blood count. However, it’s important to take note if you get infections every now and then, or experience repeat infections, the doctor may suspect lymphopenia.
For some people, the most common symptom is fever and flu-like illness.
Incidental lymphopenia and mortality: a prospective cohort study Marie Warny, Jens Helby, Børge Grønne Nordestgaard, Henrik Birgens and Stig Egil Bojesen CMAJ January 13, 2020 192 (2) E25-E33; DOI: https://doi.org/10.1503/cmaj.191024