Basophils and Other White Blood Cells

Small but mighty, they help to protect the body from infection

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White blood cells exist in far fewer numbers than red blood cells. Specifically, there is one white blood cell per 700 red blood cells (erythrocytes). White blood cells are most important in immune function and inflammation, whereas, red blood cells carry oxygen on their hemoglobin component and oxygenate our bodies.

All blood cells and blood elements (like platelets) are first created in the bone marrow, a process called hematopoiesis. Bone marrow is one of the most active organs in our body because it's constantly producing blood cells.

What Are Basophils?

Basophils are a type of white blood cell produced in the bone marrow and circulate in the blood. They are also found outside blood vessels throughout many tissues in the body.

Although basophils protect the body by killing bacteria and parasites (including external parasites such as ticks), they also can cause problems when they react incorrectly. This is what's behind the symptoms of allergies, asthma, and other inflammatory reactions in the body.

Basophils contain histamine and heparin, a blood thinning substance produced by the body. The histamine that is released by basophils (and mast cells) is the source of the symptoms of common seasonal allergies such as watery eyes, itchy skin, and runny nose. This is why antihistamines, which block the actions of histamine, are effective for reducing these symptoms.

Basophils are part of the innate immune system, which means that they can non-specifically destroy any invaders that they encounter in the body, such as bacteria and parasites. Non-specifically means that basophils do not have to recognize the invader specifically, but instead simply recognize the invader as something that should not be present and should be destroyed.

Other Types of White Blood Cells

Basophils make up about 0.5 percent of the total number of white blood cells. The other types of white blood cells are:

Eosinophils contribute to the inflammatory response and also attack parasites that are too large to be engulfed or swallowed up. Furthermore, eosinophils take part in certain allergic reactions.

Neutrophils. These cells travel to sites of injury and infection. Neutrophils contain potent enzymes that kill bacteria. They then engulf or consume broken-down bacteria. Neutrophils are the body's first line of defense against bacteria and are integral to normal immunity. Neutrophils are the most numerous of cells produced by the bone marrow. Neutrophils are short-lived and last only for about eight hours. When there's infection in the body, immature neutrophils, released from the bone marrow, accompany mature neutrophils to the site of infection. The presence of immature neutrophils in the blood is termed left shift and is an indicator of infection severity.

Monocytes. These cells usually hang out in body tissues where they consume bacteria in a process called phagocytose or prepare bacteria for presentation to lymphocytes, another type of white blood cell important for immunity. On a blood smear, monocytes are the largest blood cells seen.

Lymphocytes. Lymphocytes leave the bone marrow early and mature in circulation. These cells have the crucial role of recognizing "self" from "nonself" and modulate nearly all aspects of immune function.