Interleukin 5 (IL-5) has also been described as B-cell growth factor II due to induction to proliferation and secretion of immunoglobulins by activated B cells. It belongs to the group of cytokines that include IL-3, IL-5, and GM-CSF. Many other activities have also been attributed to this cytokine, including the development and differentiation of eosinophils from bone marrow stem cells, induction of IL-2R membrane receptor expression in activated B cells, and increased IgA secretion by LPS-stimulated B-cells. IL-5 is produced by the Th2 subpopulation of helper T-cells, while smaller amounts are secreted by activated eosinophils and mast cells. The range of biological activities of IL-5 in B cells as well as other cell types suggests that IL-5 plays an important functional role in the activities of Th2 cells. IL-5 is a highly glycosylated glycoprotein with a molecular weight of 45 to 60 kDa.
In humans, IL-5 primarily affects eosinophilic cells and promotes their differentiation, maturation, activation, migration, and survival. Although eosinophilic lung infiltration is a feature of allergic asthma that may be due to IL-5, the therapeutic administration of anti-IL-5 antibodies did not appear to alter the symptoms of asthma in clinical trials. Administration of anti-IL-5 antibodies can, however, reduce circulating eosinophils by 50% and has shown good efficacy in the treatment of the hypereosinophilic syndrome. IL-5 has also been reported to be a differentiating factor for basophils and may promote basophils to secrete histamine and leukotrienes.
Important Note
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. The correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings, and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.
