IL-33/ST2 Axis Plays a Protective Effect in Streptococcus pyogenes Infection through Strengthening of the Innate Immunity

Significant Correlation Between Cutaneous Abundance of Streptococcus and Psoriasis Severity in Patients with FBXL19 Gene Variants

Psoriasis results from both genetic predisposition and environmental triggers, such as Streptococcal infections. This study aimed to explore the correlation between the abundance of the Streptococcus genus on the skin and psoriasis severity in individuals carrying specific psoriasis-associated genetic variants. Studying 39 chronic plaque psoriasis patients, the elbow skin microbiome and 49 psoriasis-related single nucleotide polymorphisms (SNPs) were analysed using a MiSeq instrument for 16S rDNA sequencing, and CLC Genomic Workbench for processing and analysis. Through multivariate linear regression analysis, a positive correlation was found between Streptococcus genus abundance and psoriasis severity in patients with certain FBXL19 gene-related heterozygous SNPs (rs12924903, rs10782001, rs12445568). Conversely, a negative association was observed in patients with homozygous genotypes. Moreover, we identified an association between Streptococcus abundance and psoriasis severity in patients with genetic variants related to IL-22, ERAP1, NOS2, and ILF3. This is the first study highlighting a positive association between Streptococcus skin colonization and psoriasis severity in patients with heterozygous genotypes within the FBXL19 gene region. FXBL19 targets the IL-33/IL1RL1 axis, crucial in infectious diseases and innate immunity promotion. These novel results suggests an intricate interaction among host genetics, Streptococcus skin colonization, and psoriasis inflammation, offering potential avenues for novel treatment approaches.

The Role of the IL-33/ST2 Axis in CpG-Induced Macrophage Activation Syndrome

Background

Macrophage activation syndrome (MAS) is a fatal inflammatory condition, which is often associated with the elevation of multiple proinflammatory cytokines and multiple organ dysfunction. Previous studies have shown that ST2 contributes to T cell overactivation and plays a detrimental role in mouse models of primary hemophagocytic lymphohistiocytosis. The purpose of this study was to investigate the role of the IL-33/ST2 axis in a mouse model of MAS induced by repeated injections of cytosine-phosphate-guanine (CpG).

Methods

Serum cytokines were determined using the cytometric bead array by flow cytometry. IL-33 and ST2 were detected by immunohistochemistry and real-time quantitative PCR in the liver and spleen of mice. CD3 and F4/80 in the liver were detected by immunohistochemistry. Inflammatory macrophages and effector memory T lymphocytes were detected by flow cytometry.

Result

The CpG-induced MAS model was successfully induced after repeated CpG injections, presenting with hypercytokinemia and hepatosplenomegaly. The numbers of IL-33 positive cells in the liver and spleen decreased significantly, while the expression of ST2 in the liver tended to increase in the mice with MAS. IL-33 and St2 knockout mice showed similar levels of hepatosplenomegaly, peripheral blood count, and cytokine storm when compared with wild-type (WT) mice after induction of MAS. There were also no significant differences in liver pathology (including inflammatory cell infiltration of CD3 and F4/80) and levels of splenic inflammatory macrophages and effector memory T cells between the WT and knockout mice.

Conclusion

These results suggested that IL-33 decreased in the liver and spleen tissues of MAS mice. Further results suggest that IL-33 and St2 knockout mice have no treatment potential in CpG-induced MAS. Thus, the IL-33/ST2 axis has little effect on the prognosis of CpG-induced MAS.

Th1/Th2 cytokine levels: A potential diagnostic tool for patients with necrotizing fasciitis

INTRODUCTION

Necrotizing fasciitis (NF) has emerged as rare but rapidly progressive, life-threatening severe skin and soft tissue infection. We conducted a study to investigate whether Th1/Th2 cytokines could serve as biomarkers to distinguish NF from class III skin and soft tissue infections (SSTIs).

METHODS

A retrospective review was performed for 155 patients suffering from serious skin and soft tissue infections from October 2020 to February 2022. Th1/Th2 cytokines were obtained from peripheral blood and wound drainage fluid samples. Data on demographic characteristics, causative microbiological organisms, Th1/Th2 cytokines, c-reactive protein, procalcitonin and white blood cell (WBC) were extracted for analysis. Factors with statistical difference(p < 0.1) were included in the multivariate logistic regression model. The clinical differential diagnostic values of interleukin-2(IL-2), IL-6, IL-10, tumor necrosis factor-α (TNF-α) and interferon-r (IFN-r) were analyzed by receiver operating characteristic (ROC) curve.

RESULTS

Among the 155 patients, 66(43%) patients were diagnosed as NF. We found no significant difference for sex, age, location of infection, coexisting condition, predisposition, duration of symptoms before admission and micro-organisms, WBC, procalcitonin and c-reactive protein in NF and class III SSTIs group. NF had higher levels of IL-6 in serum (50.46 [24.89, 108.89] vs. 11.87 [5.20, 25.32] pg/ml; p＜0.01), IL-10 in serum (3.45 [2.03, 5.12] vs. 2.51 [1.79, 3.29] pg/ml; p＜0.01), IL-2 in wound drainage fluid (0.89 [0.49, 1.33] vs. 0.63 [0.14, 1.14] pg/ml; p = 0.02), IL-6 in wound drainage fluid (5000.84 [1392.30, 13287.19] vs. 1927.82 (336.65, 6759.27) pg/ml; p＜0.01), TNF-a in wound drainage fluid (5.20 [1.49, 22.97] vs. 0.96 [0.12, 3.21] pg/ml; p＜0.01) and IFN-r in wound drainage fluid (1.32 [0.47, 4.62] vs. 0.68 [0.10, 1.88] pg/ml; p = 0.02) as compared to the class III SSTIs. Multivariate logistic regression analyses showed that IL-6 in serum, IL-10 in serum and TNF-a in wound drainage fluid exhibited independently significant associations with diagnosis of NF(p＜0.05). In ROC curve analysis of IL-2, IL-6, IL-10, TNF-a and IFN-r for diagnosis of NF, the area under the curve (AUC) of IL-6 in serum could reach to 0.80 (p＜0.001). Using 27.62 pg/ml as the cut off value, the sensitivity was 74% and the specificity was 79% in IL-6 in serum.

CONCLUSIONS

Th1/Th2 cytokines, IL-6 in serum in particular, are potential biomarkers for the diagnosis of NF in the early stage. However, larger patient populations with multiple centers and prospective studies are necessary to ensure the prognostic role of Th1/Th2 cytokines.

Dual Immune Regulatory Roles of Interleukin-33 in Pathological Conditions

Interleukin-33 (IL-33), a member of the IL-1 cytokine family and a multifunctional cytokine, plays critical roles in maintaining host homeostasis and in pathological conditions, such as allergy, infectious diseases, and cancer, by acting on multiple types of immune cells and promoting type 1 and 2 immune responses. IL-33 is rapidly released by immune and non-immune cells upon stimulation by stress, acting as an “alarmin” by binding to its receptor, suppression of tumorigenicity 2 (ST2), to trigger downstream signaling pathways and activate inflammatory and immune responses. It has been recognized that IL-33 displays dual-functioning immune regulatory effects in many diseases and has both pro- and anti-tumorigenic effects, likely depending on its primary target cells, IL-33/sST2 expression levels, cellular context, and the cytokine microenvironment. Herein, we summarize our current understanding of the biological functions of IL-33 and its roles in the pathogenesis of various conditions, including inflammatory and autoimmune diseases, infections, cancers, and cases of organ transplantation. We emphasize the nature of context-dependent dual immune regulatory functions of IL-33 in many cells and diseases and review systemic studies to understand the distinct roles of IL-33 in different cells, which is essential to the development of more effective diagnoses and therapeutic approaches for IL-33-related diseases.