Serum VEGF-C as an evaluation marker of disease activity in adult-onset Still's disease

The landscape of innate and adaptive immune cell subsets in patients with adult-onset Still's disease

OBJECTIVE

Adult-onset Still's disease (AOSD) is a systemic autoinflammatory disorder. The understanding of the changes in adaptive immune cells and the crosstalk between innate and adaptive immune systems in AOSD is limited. This study aimed to examine the peripheral immune cell composition and inflammatory protein levels in AOSD patients.

METHODS

Twenty-nine active AOSD patients were enrolled. Flow cytometry was used to analyse the cell populations in peripheral blood. Antibody chips were utilized to detect the protein expression profile in serum.

RESULTS

In active AOSD patients, there was an increase in the percentage of classical and non-classical monocytes among peripheral blood mononuclear cells. The proportion of natural killer (NK) cells decreased, with an increase in CD56dim NK1 cells and a decrease in CD56bright NK2 cells compared with healthy controls (HCs). The percentage of naïve central memory T cells was decreased, while the percentage of effector and effector memory T cells was increased among adaptive lymphocytes. The proportion of naïve B and memory B cells was decreased, while plasma cells were increased in AOSD patients, indicating activation of the adaptive immune system. Additionally, the serum levels of 40 proteins were elevated in AOSD patients, primarily involved in cytokine-cytokine receptor interaction, inflammatory response and regulation of mitogen-activated protein kinase cascade.

CONCLUSION

Our findings showed the activation of the innate and adaptive immune system in AOSD. The protein-protein interaction analysis suggested potential communication between innate and adaptive cell subsets. These findings provide new insights into the pathogenesis of the disease and the development of targeted therapies.

Recent advances and evolving concepts in Still's disease

Still's disease is a rare inflammatory syndrome that encompasses systemic juvenile idiopathic arthritis and adult-onset Still's disease, both of which can exhibit life-threatening complications, including macrophage activation syndrome (MAS), a secondary form of haemophagocytic lymphohistiocytosis. Genetic insights into Still's disease involve both HLA and non-HLA susceptibility genes, suggesting the involvement of adaptive immune cell-mediated immunity. At the same time, phenotypic evidence indicates the involvement of autoinflammatory processes. Evidence also implicates the type I interferon signature, mechanistic target of rapamycin complex 1 signalling and ferritin in the pathogenesis of Still's disease and MAS. Pathological entities associated with Still's disease include lung disease that could be associated with biologic DMARDs and with the occurrence of MAS. Historically, monophasic, recurrent and persistent Still's disease courses were recognized. Newer proposals of alternative Still's disease clusters could enable better dissection of clinical heterogeneity on the basis of immune cell profiles that could represent diverse endotypes or phases of disease activity. Therapeutically, data on IL-1 and IL-6 antagonism and Janus kinase inhibition suggest the importance of early administration in Still's disease. Furthermore, there is evidence that patients who develop MAS can be treated with IFNγ antagonism. Despite these developments, unmet needs remain that can form the basis for the design of future studies leading to improvement of disease management.

Dysregulation of Lymphatic Endothelial VEGFR3 Signaling in Disease

Vascular endothelial growth factor (VEGF) receptor 3 (VEGFR3), a receptor tyrosine kinase encoded by the FLT4 gene, plays a significant role in the morphogenesis and maintenance of lymphatic vessels. Under both normal and pathologic conditions, VEGF-C and VEGF-D bind VEGFR3 on the surface of lymphatic endothelial cells (LECs) and induce lymphatic proliferation, migration, and survival by activating intracellular PI3K-Akt and MAPK-ERK signaling pathways. Impaired lymphatic function and VEGFR3 signaling has been linked with a myriad of commonly encountered clinical conditions. This review provides a brief overview of intracellular VEGFR3 signaling in LECs and explores examples of dysregulated VEGFR3 signaling in various disease states, including (1) lymphedema, (2) tumor growth and metastasis, (3) obesity and metabolic syndrome, (4) organ transplant rejection, and (5) autoimmune disorders. A more complete understanding of the molecular mechanisms underlying the lymphatic pathology of each disease will allow for the development of novel strategies to treat these chronic and often debilitating illnesses.

The Relationship between VEGFC Gene Polymorphisms and Autoimmune Thyroiditis

Background

Autoimmune thyroid diseases (AITDs), representative autoimmune diseases, mainly consist of Graves' disease (GD) and Hashimoto's thyroiditis (HT). In this passage, we investigated the association between vascular endothelial growth factor C (VEGFC) gene polymorphisms and AITDs.

Methods

A total of 1084 patients with AITDs and 794 healthy controls were tested for VEGFC gene genotypes in four single nucleotide polymorphisms (SNPs) by high-throughput sequencing, and the correlation between VEGFC gene polymorphisms and AITDs was statistically analyzed.

Results

The genotype distribution of rs3775194 was statistically associated with AITDs compared with the control group. Rs3775194 was associated with AITDs under the overdominant model, both before and after adjusting for confounding factors, while the other three SNPs were not associated with GD and HT. There was a prominent discrepancy between male healthy controls and male AITD patients under overdominant model in rs3775194 and the recessive model in rs11947611. The genotype distribution of rs3775194 was statistically related to male HT.

Conclusion

These results reveal the correlation between VEGFC mutation and AITD susceptibility.