Is it red blood cells or white blood cells that fight infection?

Is it red blood cells or white blood cells that fight infection?

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It's implying that red blood cells (ABO blood groups only affect the surface of red blood cells, but not white blood cells) fight disease, with type A being the weakest, and I've been reading that this is blatantly wrong, since it is white blood cells that are involved in the immune response, not red blood cells, and thus blood type would have no effect on the course of an infection because red blood cells aren't involved in fighting diseases and blood groups don't affect the internal workings of a red blood cell anyway.

I somewhat like the Daily Mail - they vacuum up information indiscriminately and empty it out at your feet. Provided you are willing to think critically, you should be alright. This report is also found at and traces back to the preprint at

Note that Medrxiv is a preprint server - the papers are not peer reviewed - hence it is another source of delight for the critical and skeptical thinker. This preprint comes from a most respectable and prolific source, but one under great pressure to publish quickly for the sake of the world. In my opinion, the authors err in their statistics - I think they assume that the odds of getting 42% instead of 32% type A blood in a sample is the odds of a group of individuals selected randomly from a large population having that much of a skew, so it seemed significant. However, if the market at Wuhan was favored by people of certain ethnic extraction, or even if there were some extended family groups in the sample, the odds of seeing this effect by chance might be higher. I won't fault them for publishing the study because people in other countries SHOULD look to see if there is a correlation in their hands. But I don't think the paper would have passed a traditional peer review.

The Difference Between Red & White Blood Cells

Blood is something far greater and more interesting than a liquid that comes out of a person when cut. Blood carries vital chemicals and nutrients throughout the human body. Blood is also considered a form of tissue.

The types of blood cells vary according to shape and function. There are several differences between red blood cells and white blood cells.

TLDR (Too Long Didn't Read)

Blood is a fluid tissue containing red and white blood cells. Red and white blood cells have many differences between them, including function and shape.

What Does a High Monocyte Count Mean?

A high monocyte count — also called monocytosis — is often associated with chronic or sub-acute infections. It can also be linked with some types of cancer, especially leukemia. A high monocyte count can occur when you are recovering from an acute infection.

Some conditions that can cause monocytosis include:

    , a heart valve infection , a lung infection , a sexually transmitted disease
  • Collagen vascular disorders, an inflammation of the collagen and joints , an inflammatory disease
  • Protozoan or rickettsial infections
  • Bone marrow recovery , which affect your blood

Care and Treatment

How is a high red blood cell count treated?

If a medical condition is causing a high red blood cell count, your doctor may recommend a procedure or medication to lower it.

In a procedure called a phlebotomy, a health professional inserts a needle into your vein and drains blood through a tube into a bag or container. You might need to have this procedure on a repeated basis until your red blood cell level is close to normal.

If you are diagnosed with the bone marrow disease polycythemia vera, your doctor may also prescribe a medicine called hydroxyurea to slow your body’s production of red blood cells. You’ll need to see your doctor regularly while taking hydroxyurea to be sure your red blood cell level does not drop too low.

Last reviewed by a Cleveland Clinic medical professional on 05/02/2018.


  • National Heart, Lung, and Blood Institute. Blood tests. Accessed 5/7/2018.
  • National Health Service. Red blood cell count. Accessed 5/7/2018.
  • American Association for Clinical Chemistry/Lab Tests Online. Red Blood Cell Count (RBC). Accessed 5/7/2018.
  • Leukemia & Lymphoma Society. Understanding blood counts. Accessed 5/7/2018.

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Functions and diseases of red and white blood cells

Red and white blood cells have two main functions: the carriage of oxygen and defence against microbial attack. The full blood count is one of the most frequently requested routine blood tests it provides key indices such as haemoglobin and the number of white cell subsets, and provides information to aid diagnosis of a range of conditions, including anaemia, infection, leukaemia, myeloma and lymphoma.

Citation: Blann A (2014) Routine blood tests 4: functions and diseases of red and white blood cells. Nursing Times 110: 8, 16-18.

Author: Andrew Blann is a consultant at City Hospital, Birmingham, and senior lecturer in medicine, University of Birmingham.

  • This article has been double-blind peer reviewed
  • Scroll down to read the article or download a print-friendly PDF including any tables and figures to see other articles in this series


Red and white blood cells have two main functions: the carriage of oxygen and defence from microbial attack respectively. Together, red cells (erythrocytes) and white cells (leukocytes) are part of the full blood count (FBC), one of the most frequently requested haematology tests.

Red blood cells

A number of red cell blood tests are used in the diagnosis, treatment and management of anaemia, polycythaemia and erythrocytosis. These are:

  • Red cell count (RBC): haemoglobin is a protein found in the red cells that carries oxygen to the tissues for cellular respiration. The red cell count reveals how many red cells the blood contains this can vary between the sexes. Lower levels are present in menstruating women in post-menopausal women, levels are still lower than in age-matched men, who produce testosterone, which stimulates red cell production. See Table 1 for reference values
  • Haematocrit (Hct): this index shows the proportion of the blood made up of red cells. It is expressed as a percentage (for example 43%) or decimal (for example 0.43)
  • Mean cell volume (MCV): this is the size of the average red cell, and is important in many cases in defining the cause of many types of anaemia.


Patients who have difficulty fulfilling basic physiological and lifestyle demands due to fatigue may have anaemia (insufficient red blood cells or haemoglobin) (Box 1). More serious signs of the condition include jaundice, hepatomegaly, angina and cardiac failure, although these may arise from other conditions.

Box 1. Signs and symptoms of anaemia

  • Pallor (especially of the conjunctiva)
  • Tachycardia (pulse rate over 100 beats per minute)
  • Glossitis (swollen and painful tongue)
  • Koilonychia (spoon nails)
  • Decreased work and/or exercise capacity
  • Fatigue, lethargy, “Tired all the time”
  • Weakness, dizziness, palpitations
  • Shortness of breath (especially on exertion)

Anaemia can be classified in a number of ways the most common are described in Box 2. Red cells are produced in the bone marrow, so infiltration of the bone marrow by cancer or other cells will inevitably lead to low numbers and therefore anaemia. A poor diet, low in iron, vitamin B12 or folate, will lead to anaemia as these are essential for the production of red cells.

Box 2. Classification of Anaemia

Depressed red cell production from the bone marrow

  • Due to infiltrating cancer
  • Due to drugs, such as the chemotherapy used to treat cancer Diet deficiency


Problems with organs may also contribute to anaemia:

  • Liver: this organ stores iron and vitamins, so liver disease may lead to anaemia (Blann, 2014)
  • Kidneys: the kidneys produce erythropoietin to stimulate the bone marrow to produce red cells, so anaemia may be present in chronic renal failure (Blann, 2014b)
  • Intestines: intestinal diseases in which iron and vitamins are unable to cross the gut wall (malabsorption) can lead to anaemia - these include gastric atrophy, inflammatory bowel diseases such as Crohn’s disease or diverticulitis surgery for gastric cancer or any cancer that requires excision of a section of bowel can also lead to anaemia.

Haemolytic anaemia is the bursting, destruction or inappropriate break-up of red cells: causes include high fever and infections such as malaria (Blann and Ahmed, 2014). The condition can also occur when antibodies erroneously bind to red cells - this is known as autoimmune haemolytic anaemia.

Red cells may be lost by an acute or chronic bleed, such as heavy menstrual periods. Hidden or prolonged internal bleeding can lead to chronic blood loss and therefore anaemia.

The most common congenital haemoglobinopathies are sickle cell disease and thalassaemia these genetic conditions are characterised by changes in haemoglobin that reduce its ability to transport oxygen.

The MCV can be used to classify anaemia. If the cells are larger than normal (macrocytes), the haemoglobin is low and the patient is symptomatic, macrocytic anaemia is present, for example in vitamin B12 deficiency.

Some haemoglobinopathies and iron deficient states cause cells to be small (microcytes), leading to microcytic anaemia.

Normocytic anaemia is associated with normal-sized cells (normocytes) but a lower overall haemoglobin level. A prime reason for a normocytic anaemia is the sudden loss of a large number of healthy red cells, perhaps by an accident or bleeding gastrointestinal cancer.

Treatment of anaemia

Anaemia and its symptoms cannot be treated without a full understanding of the aetiology of the condition.

For example, dietary iron supplements will not help anaemia caused by malabsorption, but intravenous iron may increase haemoglobin levels and so address symptoms such as fatigue and lethargy. Patients with vitamin B12 deficiency should receive regular injections of this vitamin.

Anaemia can be caused by certain drugs, such as methyldopa, some antibiotics and hydrochlorothiazide. This should resolve when the patient stops taking the drug, ideally as soon as possible - if necessary substituting it with an alternative drug. In some cases, such as in cancer chemotherapy, cessation or substitution may not be possible, so the anaemia and its symptoms are treated by blood transfusion.

Autoimmune haemolytic anaemia may be treatable with immunosuppression.

However, some forms of anaemia, such as those caused by thalassaemia and sickle cell disease, are effectively incurable (except by bone marrow transplantation) and symptoms are managed by specialist teams.

Increased levels of red cells

There are two types of disease where the concentration of red cells is higher than normal: both are characterised by raised haemoglobin and Hct.

  • Polycythaemia: this may arise from a rare malignancy of the bone marrow
  • Erythrocytosis: this is often a result of the bone marrow’s response to reduced circulating levels of oxygen, often caused by heavy smoking.

White blood cells

White cells (leucocytes) defend the body from viruses, bacteria and parasites at such times, cell numbers will be raised. High concentrations are also found in rheumatoid arthritis and cancer, and after surgery. There are five types of white cells:

  • Neutrophils: making up to 70% of the white cell count, these recognise, attack and destroy bacteria
  • Lymphocytes: the second most common white blood cell (approximately 20-25% of the white cell count), are divided into two types - B lymphocytes make antibodies, while T lymphocytes destroy cells infected with viruses
  • Monocytes: these have several functions, including bacteria removal, and are active in inflammation and in repair of damaged tissues
  • Eosinophils and basophils: these cells have roles in hypersensitivity and allergy.

White cells defend the body from most microbial pathogens through two processes:

  • Inflammation: this develops rapidly and is associated with high neutrophil numbers, but can lead to the body attacking its own tissues, leading to chronic inflammation
  • An immune response, where lymphocytes are active: this develops slowly, over days or weeks, and is focused on the invading pathogen.

Inflammatory and immune responses often cooperate. For example, lymphocytes make antibodies that bind to bacteria and yeast pathogens, making them more palatable to the neutrophils and monocytes, which aids their removal. Infections occur when either or both these processes become impaired. Antibodies can also cause autoimmune diseases such as rheumatoid arthritis and thyroiditis.

Low white cell count: leucopenia

Virtually all cases of leucopenia are associated with the use of cytotoxic drugs, which can destroy white cells, increasing patients’ risk of infections. In these cases, prophylactic antibiotics may be needed, and stringent infection prevention measures are essential.

High white cell count: leucocytosis

Leucocytosis can be a normal response to infections and surgery. Pathological states associated with it include inflammatory and autoimmune diseases such as rheumatoid arthritis. The most serious cases of leucocytosis occur in leukaemia.

Leukaemia and other malignancies

The high white cell count in leukaemia is due to changes to how cells develop in the bone marrow.

Leukaemic cells stop developing prematurely, entering the blood in an immature state and increased numbers. If this process develops slowly, perhaps over several years, it is said to be chronic rapid development, for example, over months, is said to be acute.

Acute leukaemias, frequently characterised by high numbers of immature cells, are often much more aggressive than the chronic condition, and survival (unless treated) can be as short as months.

If the major affected cells in the leukaemia are of the neutrophil lineage, it is described as myeloid when lymphocytes are predominantly affected, it is known as lymphocytic leukaemia. A leukaemia dominated by blast cells is called lymphoblastic.

As leukaemia arises in the bone marrow, the production of other cells is reduced. Thus anaemia and low levels of platelets (thrombocytopenia, with a risk of bleeding and bruising) are invariably consequences of leukaemia (Table 2).

In advanced disease, leukaemia may invade the lymph nodes, liver and spleen, making them swollen (lymphadenopathy, hepatomegaly and splenomegaly respectively). Treatments are aimed at reducing the tumour burden, and are generally cytotoxic drugs. More severe leukaemias need transplantation of bone marrow stem cells from a donor or patients themselves.

Differential diagnoses of leukaemia

White cell counts may also be raised in severe infections. The most dangerous and life-threatening is septicaemia (blood poisoning), where the blood itself is infected with bacteria. Patients with septicaemia are usually cared for in intensive care units on high doses of intravenous antibiotics.

Other lymphoid cancers

Lymphoma involves malignant lymphocytes taking over lymph nodes: principle examples are Hodgkin and non-Hodgkin lymphomas. Lymphomas often progress to affect more lymph nodes the spleen, liver and bone marrow (therefore possibly leading to anaemia) can become involved.

Important differential diagnoses of lymphoma are self-limiting cases of lymphadenopathy, which may occur in tonsillitis or a nearby infected wound.

Myeloma is a tumour of B lymphocytes, which normally make antibodies to attack pathogens it is found in the bone marrow. Myeloma cells may make large amounts of an incorrect type of antibody, causing a high erythrocyte sedimentation rate.

Key points

  • Red blood cells’ main function is transport oxygen to body cells using haemoglobin
  • Lack of red blood cells leads to anaemia, which can be acute or chronic and is associated with a number of diseases
  • White blood cells defend the body from infection with bacteria, viruses or parasites
  • Different types of white cells perform different functions
  • Raised levels of white cells can be a sign of infection or a malignant condition such as leukaemia

Also in this series

Blann AD (2014a) Routine blood tests 2: what is the purpose of liver function tests? Nursing Times. 110: 6, 17-19.
Blann A (2014b) Routine blood tests 1: why do we test for urea and electrolytes? Nursing Times 110: 5, 19-21.
Blann AD, Ahmed N (2014) Blood Science: Principles and Pathology. Chichester: Wiley Blackwell.

Further reading
Blann AD (2013) Routine Blood Tests Explained. Keswick: M&K Update.

Platelets help blood to clot

A diagram of a platelet in Albert's
Molecular Biology of the Cell

As with all the cells in the blood, platelets originate from stem cells in the bone marrow. The stem cells develop into platelet precursors (called megakaryocytes) that "shed" platelets into the bloodstream. There, platelets circulate for about 9 days. If they encounter damaged blood vessel walls during this time, they stick to the damaged area and are activated to form a blood clot. This plugs the hole. Otherwise, at the end of their life span they are removed from the circulation by the spleen. In a diverse number of diseases where the spleen is overactive, e.g. rheumatoid arthritis and leukemia, the spleen removes too many platelets, leading to increased bleeding.

What is white blood cells in biology?

White blood cells (WBCs), also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders.

Furthermore, what are the 5 types of white blood cells and their functions? The five main types of blood cells are basophils, neutrophils, eosinophils, monocytes, and lymphocytes. Basophils are the cells mainly responsible for allergic reactions. They defend against parasites and bacteria by excreting two chemicals: heparin and histamine.

Herein, what are the 3 things white blood cells do?

They flow through your bloodstream to fight viruses, bacteria, and other foreign invaders that threaten your health. When your body is in distress and a particular area is under attack, white blood cells rush in to help destroy the harmful substance and prevent illness. White blood cells are made in the bone marrow.

How are white blood cells produced?

Red blood cells, most white blood cells, and platelets are produced in the bone marrow, the soft fatty tissue inside bone cavities. Two types of white blood cells, T and B cells (lymphocytes), are also produced in the lymph nodes and spleen, and T cells are produced and mature in the thymus gland.

Elevated White Blood Cell Counts

Though you may think of infections, there are many causes of an elevated white blood cell count. These can be increased by overproduction, or rather by the body releasing white blood cells early from the bone marrow.

Stress of any form can also result in this release of white blood cells. Some causes of an increased white blood cell count include:  

  • Infections
  • Cancers such as leukemias, lymphomas, and myelomas in which a greater number of white blood cells are manufactured
  • Inflammation such as inflammatory bowel disease and autoimmune disorders
  • Trauma ranging from fractures to emotional stress
  • Pregnancy
  • Asthma and allergies
  • Exercise

In severe infections, young-appearing white blood cells, called blasts, often appear in the blood due to the body's attempt to get as many white blood cells on the scene as quickly as possible.

Beta-carotene converts to vitamin A in your body and offers the same white blood cell-boosting benefits. It increases the number of T cells, white blood cells that fight infection and cells that naturally kill off harmful bacteria and viruses. Brightly colored vegetables, particularly those that are yellow, red and orange, contain the most beta-carotene. Good choices include carrots, squash, leafy green vegetables, sweet potatoes, spinach and bell peppers.

  • Beta-carotene converts to vitamin A in your body and offers the same white blood cell-boosting benefits.
  • Brightly colored vegetables, particularly those that are yellow, red and orange, contain the most beta-carotene.


Leukemia is a type of cancer found in your blood and bone marrow and is caused by the rapid production of abnormal white blood cells. These abnormal white blood cells are not able to fight infection and impair the ability of the bone marrow to produce red blood cells and platelets.

Leukemia can be either acute or chronic. Chronic leukemia progresses more slowly than acute leukemia, which requires immediate treatment. Leukemia is also classified as lymphocytic or myelogenous. Lymphocytic leukemia refers to abnormal cell growth in the marrow cells that become lymphocytes, a type of white blood cell that plays a role in the immune system. In myelogenous leukemia, abnormal cell growth occurs in the marrow cells that mature into red blood cells, white blood cells, and platelets. There are four broad classifications of leukemia:

  • Acute lymphocytic leukemia (ALL)
  • Acute myelogenous leukemia (AML)
  • Chronic lymphocytic leukemia (CLL)
  • Chronic myelogenous leukemia (CML)

Leukemia occurs in both adults and children. ALL is the most common form ofchildhood leukemia, and AML is the second most common. Decades of research have led to vastly improved outcomes for children diagnosed with ALL. The two most common adult leukemias are AML and CLL.

Am I at Risk?

Although experts are uncertain about the causes of leukemia, they have identified several risk factors that include the following:

  • Exposure to high levels of radiation
  • Repeated exposure to certain chemicals (for example, benzene)
  • Chemotherapy
  • Down Syndrome
  • A strong family history of leukemia

Symptoms vary depending on the type and stage of leukemia, but they can include the following:

  • Fever, chills, night sweats and other flu-like symptoms
  • Weakness and fatigue
  • Swollen or bleeding gums
  • Headaches
  • Enlarged liver and spleen
  • Swollen tonsils
  • Bone pain
  • Paleness
  • Pinhead-size red spots on the skin
  • Weight loss

How Is Leukemia Treated?

Your doctor will conduct a complete blood count (CBC) to determine if you have leukemia. This test may reveal if you have leukemic cells. Abnormal levels of white blood cells and abnormally low red blood cell or platelet counts can also indicate leukemia. If you test positive for leukemia, your doctor will perform a biopsy of your bone marrow to determine which type you have.

Treatment depends on your age, general health, and type of leukemia. You might receive a combination of treatments that could include chemotherapy, biological therapy, radiation therapy, and stem cell transplantation. Patients with acute leukemia often undergo chemotherapy because this type of treatment targets fast-dividing cells. Many acute leukemia patients have responded successfully to treatment. On the other hand, because the cells divide more slowly in chronic leukemia, it is better treated with targeted therapies that attack slowly dividing cells as opposed to traditional chemotherapy that targets rapidly dividing cells.

For some patients, participating in a clinical trial provides access to experimental therapies. If you are diagnosed with leukemia, talk with your doctor about whether joining a clinical trial is right for you.

Is Leukemia Preventable?

Because the cause of leukemia remains unknown, there is no certain way to prevent it. However, avoiding exposure to solvents, such as benzene and toluene, and unnecessary exposure to x-rays is generally good practice. If you think you may be exhibiting signs of leukemia, being aware of the risk factors and symptoms and talking with your doctor are critical to early diagnosis and treatment. It is especially important for people who have a family history of leukemia to be aware of symptoms and share their family medical history with their doctors.

Chronic Myeloid Leukemia: A Patient's Journey

Where Can I Find More Information?

If you find that you are interested in learning more about blood diseases and disorders, here are a few other resources that may be of some help:

Results of Clinical Studies Published in Blood

Search Blood, the official journal of ASH, for the results of the latest blood research. While recent articles generally require a subscriber login, patients interested in viewing an access-controlled article in Blood may obtain a copy by e-mailing a request to the Blood Publishing Office.

Patient Groups

A list of Web links to patient groups and other organizations that provide information.

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