Interleukin-38 (IL-38) is a member of the interleukin-1 (IL-1) family and the interleukin-36 (IL-36) subfamily.
It is important for the inflammation and host defense.
IL-38 is expressed in the skin as well as in the tonsils.
It regulates both innate and adaptive immunity. It binds to the soluble IL-1RI receptor.
It is expressed in basal epithelia of skin, in proliferating B cells of the tonsil, in spleen and other tissues.
IL-38 is from the IL-1RN gene.
This cytokine has 41% homology with IL-1Ra and 43% homology with IL-36Ra.
IL-38 is expressed in skin, spleen, tonsil, thymus, heart, placenta and fetal liver.
When the activation of inflammatory response occurs the expression of IL-38 is changed: spondylitis ankylopoetica,
cardiovascular disease, rheumatoid arthritis, or hidradenitis suppurativa.
IL-38 could play an important role in rheumatic diseases.
IL-38 is also one of the five proteins which are related with C-reactive protein (CRP) levels in the serum, and may play role also in inflammatory diseases as cardiovascular disease.
Patients with SLE had higher concentrations of IL-38 in the serum than healthy patients and also patients with active disease had higher concentrations of IL-38 in the serum than patients with inactive form.
Biopsy of gland of patients with primary Sjogren’s disease shows that the expression of IL-38 is increased.
IL-38 was found also in the synovium of patients with rheumatoid arthritis.
IL-38 could have anti-inflammatory properties in rheumatoid arthritis and probably could be use in a therapeutic strategy.