Interleukin 17 Blood Test

What is the purpose of this test?

Order this Interleukin-17 (IL-17) Blood Test, which measures the amount of IL-17 in the blood. Interleukin-17 (IL-17) and IL-17-producing cells have been shown to play essential roles in inflammation and the immune response. IL-17 is believed to be mainly produced by T helper 17 (Th17) cells, a unique helper T-cell subset different from Th1 and Th2 cells. Other subsets of T cells, such as γδT and natural killer T (NKT) cells, have also been found to produce IL-17 in response to innate stimuli. IL-17 acts as a proinflammatory cytokine that can induce the release of specific chemokines, cytokines, matrix metalloproteinases (MMPs), and antimicrobial peptides from mesenchymal and myeloid cells. This leads to the expansion and accumulation of neutrophils in the innate immune system and links innate and adaptive immunity in vivo.

Furthermore, increasing evidence indicates that IL-17 and IL-17-producing cells are involved in the pathogenesis of various diseases such as:

• Allergies
• Autoimmune diseases
• Allograft transplantation
• Malignancy

They may also play protective roles in host defense against infectious diseases and promote the induction of cytotoxic T lymphocyte (CTL) responses against cancer. In addition, targeting the IL-17 axis is under investigation for treating inflammatory disorders.

What other diseases or conditions are associated with IL-17?

The IL-17 family has six subtypes: 

• IL-17A
• IL-17B
• IL-17C
• IL-17 D
• IL-17E (also known as IL-25)
• IL-17F

Specific subtypes of IL-17 are related to various diseases and conditions, such as:

• IL-17A - plays a central role in the pathogenesis of psoriasis. This was shown in several studies with the successful use of inhibiting antibodies. It acts on non-hematopoietic cells, particularly epithelial cells, and plays an essential role in the immune response in neighboring organs. In the skin, IL-17A increases proliferation, alters keratinocyte differentiation, and induces antimicrobial peptides and chemokines.
• IL-17A - also has a role in other inflammatory diseases. For example, elevated IL-17A concentrations have been measured in patients with multiple sclerosis (MS), rheumatoid arthritis, and acute coronary syndrome that correlated with parameters of systemic inflammation.
• IL-17F - Increased serum levels of IL-17F have been associated with elevated autoantibody levels in primary Sjögren’s syndrome (pSS).