Leukocytes are white blood cells, and the human body has five different types that travel through the blood stream and play a critical role in protecting us from diseases. Each class of leukocytes plays a different role, but they work in unison--like an army--to combat threats, including bacterial infections, parasites and viruses. The number of leukocytes rises in the presence of a threat, and white blood cell counts can indicate the presence of an otherwise undetectable disease.
Neutrophils
Neutrophils are designed to protect the body from bacterial or fungal infections. They normally constitute more than half of the white blood cells in blood. Neutrophils are the immune system's first responders to foreign substances and are designed to kill bacteria and other pathogens. Neutrophils are found in large numbers when the body is wounded. Signs that neutrophils are preventing the spread of a bacterial infection include acute inflammation and visible pus, created from the large amount of dead bacterial cells. Neutrophils cannot sustain themselves and die after killing a few pathogens. A low neutrophil count indicates a greater chance of bacterial infection.
Eosinophils
While neutrophils fight bacteria and fungus, eosinophils are designed to battle parasites and parasitic-related infections. Eosinophils normally constitute one to three percent of the blood's leukocytes. If a larger number are detected in a blood test, it can indicate the presence of a parasite. The eosinophil count also rises during allergic reactions, which occur when the body senses a threat that is actually harmless. These cells contribute to allergic symptoms, such as hay fever, asthma and hives.
Basophils
Basophils are chiefly responsible for releasing histamines, the chemical that produces an inflammation in response to injury. They travel through the bloodstream to the injury site and are partially responsible for causing swelling, warmth and redness, which are all signs that the body is fighting foreign invaders. Basophils are normally barely present in the blood stream, constituting less than one percent of the body's total white blood cell count. Higher-than-average basophil counts may indicate some types of anemia or bone marrow-related diseases.
Lymphocytes
Lymphocytes are associated with the body's lymphatic system. They break down into three types: B-cells, T-cells and natural killer cells, all of which are critical to immune response systems. B-cells make antibodies that "stick" to pathogens, leaving them vulnerable to attack. T-cells "coordinate" the immune response and help kill some virus-infected and tumor cells. Natural killer cells "listen" to T-cell commands and destroy cells that contain viruses or have become cancerous. Lymphocytes are small and plentiful in the bloodstream, as well as the lymphatic system.
Monocytes
Monocytes are the largest class of leukocytes and are designed to surround, devour and digest pathogens and microorganisms. They are hardier than neutrophils, and also deliver pathogens to lymphocytes to start the production of antibodies to combat specific infections and diseases. Monocytes also act as the body's "vacuum cleaners" by removing unnecessary cells and material from the body. Monocytes typically make up less than 10 percent of all white blood cells; higher numbers may indicate malaria, typhoid or endocarditis.
Tags: white blood, blood cells, white blood cells, bacterial infection, blood cell, blood stream, class leukocytes