A cytokine is one of the most important parts of the immune system. The immune system requires a system of signaling from cells in the body as a call for help; this is perhaps the best cytokine definition available. When a cell is damaged or invaded by a pathogen, macrophages and the damaged cells will secrete a cytokine – these include factors like interleukins, interferon, and tumor necrotizing factor alpha. The latter also proving that the destruction of tumor tissue is controlled by the immune system. When cytokines are released they call upon specific immune cells from the immune system like the white blood cells, and T and B cells.
These cytokines also signal the exact purpose that these cells have to perform. Cytokines and antibodies are completely different, as antibodies are what bind to antigens and allow the immune system to identify invaders. Therefore, a good analogy would be that cytokines are a general alert to an invader, and an antibody is the scout for the invader. The process of analyzing cytokines is called a cytokine assay.
A cytokines assay is usually employed to check for the specific cytokines being secreted. This is more a function of biochemistry research rather than a specific test for body functions. Cytokines and their receptors are under a great deal of research because of their role in disease control. It is worth noting that many cytokines have an opposing and sometimes complimentary effect to each other; thereby, modulating the severity of the immune response. Cytokine assays are used to identify which cytokines and their deficiencies are responsible for the cause of some autoimmune diseases.
A cytokine assay would most likely be a blood test because cytokine release is not done in an endocrine method since the target of action has to be very specifically defined; otherwise, healthy tissue would end up being unnecessarily damaged.
There are no preparations for this test at all. It is worth noting that there is an aberrant secretion of cytokines that sometimes occurs called the cytokine storm. This is when the cytokine release is not modulated and the body mounts a tremendous immune response in a region of the body. This causes the destruction of healthy tissue. This can happen sometimes in the case of a flu, especially swine flu, and can sometimes prove extremely fatal to a patient.