Altered serum levels of IL-36 cytokines (IL-36α, IL-36β, IL-36γ, and IL-36Ra) and their potential roles in Guillain-Barré syndrome

Emerging Role of the IL-36/IL-36R Axis in Multiple Inflammatory Skin Diseases

IL-36 is a most recent member of the IL-1 cytokine family, primarily expressed at barrier sites of the body such as the skin, lungs, and intestine. It plays a vital role in inflammation and is implicated in the development of various cutaneous; intestinal; and pulmonary disorders, including psoriasis, inflammatory bowel disease, and chronic obstructive pulmonary disease. IL-36 comprises 4 isoforms: the proinflammatory IL-36α, IL-36β, and IL-36γ and the anti-inflammatory IL-36R antagonist. An imbalance between proinflammatory and anti-inflammatory IL-36 isoforms can contribute to the inflammatory fate of cells and tissues. IL-36 cytokines signal through an IL-36R heterodimer mediating their function through canonical signaling cacade, including the NF-B pathway. Prominent for its role in psoriasis, IL-36 has recently been associated with disease mechanisms in atopic dermatitis, hidradenitis suppurativa, neutrophilic dermatoses, autoimmune blistering disease, and Netherton syndrome. The major cutaneous source of IL-36 cytokines is keratinocytes, pointing to its role in the communication between the epidermis, innate (neutrophils, dendritic cells) immune system, and adaptive (T helper [Th]1 cells, Th17) immune system. Thus, cutaneous IL-36 signaling is crucial for the immunopathological outcome of various skin diseases. Consequently, the IL-36/IL-36R axis has recently been recognized as a promising drug target for the treatment of inflammatory disorders beyond psoriasis. This review summarizes the current update on IL-36 cytokines in inflammatory skin diseases.

Extensive cytokine biomarker analysis in serum of Guillain-Barré syndrome patients

Guillain-Barré syndrome (GBS) is an acute idiopathic polyneuropathy which is related to infection and immune mechanism. The exact pathogenesis of the disease is unknown and treatment is limited. Thus, the purpose of the study is to identify biomarkers of GBS serum and elucidate their involvement in the underlying pathogenesis of GBS that could help to treat GBS more accurately. Antibody array technology was used to detect the expression levels of 440 proteins in serum of 5 GBS group and 5 healthy control group. Sixty-seven differentially expressed proteins (DEPs) were identified by antibody array, among which FoLR1, Legumain, ErbB4, IL-1α, MIP-1α and IGF-2 were down-regulated, while 61 proteins were up-regulated. Bioinformatics analysis indicated that most DEPs were associated with leukocytes, among which IL-1α, SDF-1b, B7-1, CD40, CTLA4, IL-9, MIP-1α and CD40L were in the center of protein-protein interaction (PPI) network. Subsequently, the ability of these DEPs to distinguish GBS from healthy control was further evaluated. CD23 was identified by means of Random Forests Analysis (RFA) and verified by enzyme-linked immunosorbent assay (ELISA). The ROC curve result of CD23 respectively displayed that its sensitivity, specificity and AUC were 0.818, 0.800 and 0.824. We speculate that activation of leukocyte proliferation and migration in circulating blood might be associated with inflammatory recruitment of peripheral nerves, leading to the occurrence and development of GBS, but this conclusion still requires deeper confirmation. More importantly, central proteins may play a pivotal role in the pathogenesis of GBS. In addition, we detected IL-1α, IL-9, and CD23 in the serum of GBS patients for the first time, which may be promising biomarkers for the treatment of GBS.