Basophils are most often only considered as defenders against parasitic infections. Yet, their role in the body is much more extensive. Basophils are an important element of the immune system and play a big role in allergic reactions, inflammation, and autoimmune diseases.

What are Basophils?

Basophils are a type of white blood cells. They protect the body and help it to get rid of bacteria and parasites. Basophils also take part in allergies, asthma, and autoimmune diseases. They can be the cause of these diseases when they react too much to external or internal signals [1, 2].


The innate immune system (or inborn immunity system) is an important set of mechanisms that allow the body to defend itself against harmful substances.

Basophils are a part of the innate immune system as they can quickly react to foreign organisms and substances. They become activated when they contact with foreign molecules, IgE, or some specific signals from other cells [3, 4, 5].

Most of the functions of basophils depend on the release of heparin and histamine at the site of inflammation. They store them in special structures called granules. When basophils become activated, they release their granules [6].

Histamine expands blood vessels and increases blood flow. Heparin is a well-known anti-clotting agent. It also helps to maintain proper blood flow by balancing clotting processes. This allows all necessary cells and substances to get to the site of inflammation from the bloodstream [7, 8].

Activated basophils are also the source of the cytokines IL-3 and IL-4. These molecules enhance the activity of both basophils themselves and other immune cells, shifting the Th1 / Th2 balance towards Th2 [6, 6, 9, 10].

Normal Range

Basophils are the least numerous white blood cells. Their number is normally around 0 to 0.20 x 10^9/L, (about 1% of your total white blood cell count) [11].

Basophil Activation Test

The basophil activation test is a blood test that assesses the degree of basophil activation caused by an allergen. It is used for diagnosing allergies to various substances, such as foods, drugs, and dust particles [12].

During the test, a specific allergen is added to whole blood, where it can activate basophils. Activated basophils have specific molecules on the membrane (CD63 or CD203c), which help to recognize them. However, there are some medications (such as omalizumab) that may interfere with the result of the test [12, 13, 14, 15].

High Levels of Basophils and Related Diseases

An elevated level of basophils (above 0.20 x 109/L) is called basophilia. With basophilia, it may be easier for the body to provide improved protection against parasites or foreign substances. But usually, it is associated with the development of undesirable conditions, such as inflammation or allergy [1].

Additionally, in a study of 47 chronic myeloid leukemia patients, a high basophil count was associated with a worse prognosis [16].

Causes of Basophilia

1) Parasite Infection

Parasites in the human body produce a lot of substances that can provoke the immune system. Basophils play a crucial role in this type of immune response. They also help the body to react faster in the future to similar infections [17, 18, 19].

2) Allergic Reactions

Allergy most often involves inflammation, which is caused by activated basophils. When reacting with an allergen, basophils become activated, release their granules, and cause allergy symptoms [1].

3) Ulcerative Colitis and Crohn’s Disease

Ulcerative colitis and Crohn’s disease are different inflammatory disorders, but they share some similar traits.

While Ulcerative colitis has an allergic nature, Crohn’s disease is an autoimmune disorder. However, both of them involve inflammation, which increases basophil count [20].

4) Leukemia

Leukemia is a type of bone marrow cancer that produces blood cells. It results in high numbers of abnormal white blood cells, including basophils. Basophilia is an important marker of leukemia [21, 22, 23].

5) Rheumatoid Arthritis

Rheumatoid arthritis is an autoimmune disorder that causes joint inflammation. Juvenile rheumatoid arthritis usually causes increased levels of circulating basophils. However, adults with RA may have a reduced level of basophils [24, 25].

6) Asthma

Asthma is a serious inflammatory and allergic disease. It starts with elevated reactivity to common inhaled allergens. This disease is known for its “attacks” that cause shortness of breath and coughing [26].

Basophils play a large role in the development of asthma, but their level in the blood is usually within normal limits.

Importantly, patients with allergic asthma are sensitive to the level of basophils, and an increase indicates an impending attack [27, 28].

Low Levels of Basophils and Related Conditions

A low level of basophils is known as basopenia. Basopenia itself is not dangerous to your health, but it can be associated with some diseases [29, 1, 30].

Basophils can go from the blood to the sites of inflammation. This migration reduces their number in the blood [31, 29].

When basophils release their granules, they are no longer active. These “empty” cells are not included in basophil count during calculation [14, 31].

In such cases, low levels of basophils can serve as an additional argument while making a diagnosis [32].

Causes of Basopenia

1) Urticaria (Hives)

Urticaria (or hives) is a kind of skin rash with red and raised bumps, called wheals. They are also very itchy.

This condition is usually caused by an infection or an allergic reaction [33].

Wheals are caused by active molecules, released by basophils and mast cells. Basophils migrate from the blood to urticarial wheals during disease activity, thus causing basopenia [34, 35, 31].

2) Lupus

Lupus (systemic lupus erythematosus) is an autoimmune disease, during which the immune system attacks healthy tissues. It causes inflammation in various parts of the body (such as joints, skin, heart, and brain) [36].

The inflammatory process in lupus forces basophil accumulation in secondary lymphatic organs, such as lymph nodes, tonsils, and spleen, thus lowering basophil levels in the blood [30, 37].

3) Smoking

Smoking activates basophils and decreases the level of intact basophils. Therefore, smoking often leads to basopenia [38, 39].

However, a human study with 498 participants found basophilia in smokers [40].

4) Corticosteroids

Corticosteroids decrease both the activity of basophils and their number. If you take these kinds of drugs, your basophil level can be lowered [41, 42].

5) Anxious Depression

A study of 709 participants showed that during an anxious depression, people have decreased basophil levels. It may be associated with the involvement of inflammation in the development of this type of depression [43].

How to Change Your Basophil Activity

Basophils are able to influence their own count and activity. This ability allows allergies or inflammation to appear quickly enough. As such, it is better to keep your basophil activity low.

Ways to Decrease Basophil Activity

1) Caffeine

Caffeine directly decreases basophil activity. There are two main pathways involved: mTOR and PKA [44, 45].

2) Adrenaline

Acute stress and an increase of adrenaline (epinephrine), decrease the functional activity of basophils. Be aware that norepinephrine and chronic stress can cause quite the opposite effect [46].

3) Crocin

In a human study with 44 participants, crocin tablets (20 mg) decreased basophil count by almost 15%. Though crocin is a compound of saffron, saffron itself is quite ineffective during long-term use [47, 48].

4) α-Melanocyte-Stimulating Hormone (α-MSH)

A study showed that α-MSH reduced the response of basophils to allergens. So, anything that increases α-MSH can be also used to reduce the inflammation and allergies [49].

5) Polygoni Cuspidatum Extract

In mice, the extract inhibited the SYK signal pathway, present in both mast cells and basophils. This decreased histamine release and allergic cytokine production, and thereby had anti-allergic activity. Also, in a human study with 20 participants, the extract showed anti-inflammatory properties [50, 51].

6) Cortex Mori Radicis

A mouse study showed that cortex mori radicis decreased IgE and Th2 cytokine levels. Since they are important for basophil activation, it decreased inflammatory status [52].

7) Bulbine Natalensis Extract

Intake of bulbine natalensis extract for 7 days decreased basophil level in rats. However, it may cause hardening of the arteries (atherosclerosis) [53].

What Increases Basophil Activity

You do not want to increase basophil activity since it can cause inflammation. However, here is a list of things that may increase basophil activity, but not necessarily cause basophilia.

1) Smoking

Substances and tiny particles contained in cigarette smoke can affect basophils and mast cells. This results in an increased level of activated basophils and leads to an enhanced basophil activity. However, smoking can also cause basopenia [38, 39].

2) Antibiotics

Exposure to antibiotics in early life can result in higher asthma risks. There is speculation that this is connected to improper basophil responses. However, this connection may be indirect or inconsistent [54, 55, 1].

3) Air Pollutants

Various human and animal studies showed that tiny particles and various substances in the polluted air increase basophil activity [56, 57, 58].

4) Chronic Stress

Chronic stress negatively affects the body in many ways. It increases cortisol and norepinephrine levels, which has negative consequences for the immune system. Cortisol promotes the Th2 immune system and norepinephrine elevated basophil activity [59, 60, 61, 62].

Genes Related to Basophil Count and Activity

Basophil levels are influenced by your genes. If you’ve gotten your genes sequenced, SelfDecode can help you determine if your levels are high or low as a result of your genes, and then pinpoint what you can do about it.

If you’re sick and tired of guessing about your health, SelfDecode can help you find specific answers that conventional doctors/diagnostics may never uncover.

SNPs Affecting Basophil Count

The SNP rs4328821 in the GATA2 gene affects the basophil count directly. The protein encoded in this gene is involved in the development of blood cells. Each “A” variant increases basophil as well as eosinophil count [63].

SNPs Affecting IgE Level

There are some SNPs related to an increased IgE level. Since IgE plays a crucial role in basophil activity, an increase of the IgE level often results in heightened basophil reactivity.

Irregular Basophil Levels?

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