Immunophenotyping refers to one way a doctor can look at the protein that the human body's cells express. Normally, this procedure is performed during laboratory diagnostics and basic science research. For example, doctors can use this technique to diagnose leukemia in a patient. Although the human body has more than 300 clusters of differentiation, immunophenotyping is useful for testing white blood cells.
A cluster of differentiation (CD) is a protocol doctors use to investigate cell surface molecules on the human body's white blood cells. A CD's molecules function in a variety of ways; usually, one acts as a receptor or a ligand, which is what activates a receptor, but this isn't always the case. Other CD molecules might function as cell adhesion, which binds one cell to a surface.
Specifically, immunophenotyping involves labeling human white blood cells with certain antibodies adjacent to the surface protein, which is located on the cell's membrane. Depending on the antibodies that a doctor places onto the surface, this procedure can accurately identify which cells are leukemic. The labeled cells are then placed into a flow cytometer, an instrument that can analyze thousands of cells a second. Besides cells, doctors can perform this procedure on spinal fluid and bone marrow in just a few short hours.
Immunophenotyping can diagnose diseases in which there is some type problem with the human white blood cells. Perhaps the most common of these illnesses is leukemia, a cancerous disease in which the bone marrow supplies the body with an unusually high amount of white blood cells. Arganulocytosis is another disease caused by the destruction of neutrophil granulocytes, the most abundant kind of white blood cell.
Leukopenia is another disease similar to arganulocytosis, but it is less severe. Like its counterpart, it occurs when the white blood cell count drops below 5,000 per cubic milliliter. Leukopenia, however, is normally caused by an allergic reaction to a drug or chemical rather than direct destruction.
Finally, infectious mononucleosis is another disease characterized by the presence of abnormally formed lymphocytes in the bloodstream. It is a relatively contagious disease, and many people believe that kissing is a viable method of transmission, so it has been dubbed "the kissing disease." Also known as glandular fever, this disease is somewhat difficult to diagnose via immunophenotyping. Glandular fever incubates itself between four days and four weeks, and the patient might feel any number of symptoms. This includes a general feeling of weakness, a loss of appetite, swollen lymph nodes, a sore throat, a headache and a fever.