The role of chemokines in Henoch Schonlein Purpura

IgA vasculitis update: Epidemiology, pathogenesis, and biomarkers

Immunoglobulin A vasculitis (IgAV), formerly known as Henoch-Schönlein purpura, is the most common systemic vasculitis in children, characterized by diverse clinical manifestations with a wide spectrum ranging from isolated cutaneous vasculitis to systemic involvement. The incidence of IgAV is geographically and ethnically variable, with a prevalence in autumn and winter, suggesting a driving role that genetic and environmental factors play in the disease. Although IgAV has a certain degree of natural remission, it varies widely among individuals. Some patients can suffer from severe renal involvement and even progress to end-stage renal disease. Its pathogenesis is complex and has not been fully elucidated. The formation of galactose-deficient IgA1 (Gd-IgA1) and related immune complexes plays a vital role in promoting the occurrence and development of IgAV nephritis. In addition, neutrophil activation is stimulated through the binding of IgA to the Fc alpha receptor I expressed on its surface, resulting in systemic vascular inflammation and tissue damage. Starting from the epidemiological characteristics, this article will review the role of immunological factors such as Gd-IgA1, autoantibodies, circulating immune complexes, complement system, cellular immunization, and the contributions of environmental and genetic factors in the pathogenesis of IgAV, and conclude with the major biomarkers for IgAV.

Serum levels of selected cytokines [interleukin (IL)-17A, IL-18, IL-23] and chemokines (RANTES, IP10) in the acute phase of immunoglobulin A vasculitis in children

The pathogenesis of the immunoglobulin A vasculitis (IgAV) is still unknown. The available data shows that interleukin (IL)-17, IL-18, IL-23, regulated on activation, normal T cell expressed and secreted (CCL 5, RANTES), and interferon (IFN)-γ-inducible protein 10 (IP10) participate in the pathogenesis of IgAV by influencing the recruitment of leukocytes to the site of inflammation. The aim of this study was to analyze the serum concentration of IL-17A, IL-18, IL-23, RANTES, and IP10 in patients with acute IgAV compared to healthy children. Moreover, we wanted to assess the suitability of the levels of tested cytokines to predict the severity of the disease. All children with IgAV hospitalized in our institution between 2012 and 2017 were included in the study. Cytokines levels were determined in a serum sample secured at admission to the hospital. Basic laboratory tests have also been analyzed. IL-17A, IL-18, and IL-23 were significantly higher in whole IgAV group (52.25 pg/ml; 164.1 pg/ml and 700 pg/ml, respectively) than in the control group (27.92 pg/ml; 140.1 pg/ml and 581.5 pg/ml, respectively). The receiver operating characteristic (ROC) curve analysis revealed the largest area under the curve (AUC 0.979, p < 0.001) for the IL-17A with 95.1% sensitivity and 91.7% specificity. There were no significant differences in cytokine levels depending on the severity of the IgAV. Although the serum levels of the IL-17A, IL-18, and IL-23 increase significantly in the acute phase of the IgAV, they cannot be used as indicators of predicting the course of the disease. IL-17A seems to be a good predictor of IgAV occurrences.

Advances in our understanding of the pathogenesis of Henoch-Schönlein purpura and the implications for improving its diagnosis

Henoch-Schönlein purpura (HSP) is a leukocytoclastic vasculitis classically characterized by palpable purpura, arthritis, abdominal pain and renal disease. In this article, we summarize our current understanding of the pathogenesis of HSP and the implications for improving its diagnosis. Although the pathogenesis of HSP is not fully understood yet, exciting new information has emerged in recent years, leading to a better understanding of its pathogenesis. Here, we discuss genetic predisposition, immunoglobulins with a particular emphasis on IgA1, activated complements, cytokines and chemokines, abnormal coagulation and autoantibodies in the underlying pathogenic mechanisms. Finally, diagnostic criteria for HSP developed by institutions such as the American College of Rheumatology and the European League against Rheumatism/Paediatric Rheumatology European Society were proposed to improve early detection and diagnosis.

Lack of association between macrophage migration inhibitory factor gene promoter (-173 G/C) polymorphism and childhood Henoch-Schönlein purpura in Turkish patients

Henoch-Schönlein purpura (HSP) is a small-vessel vasculitis of autoimmune hypersensitivity with rash, arthritis, abdominal pain and renal involvements. Macrophage migration inhibitory factor (MIF) is a immunoregulatory proinflammatory cytokine, and a major mediator at the inflammatory sites. The pathogenesis of HSP has not been fully elucidated. Here we aimed to assess the influence of macrophage migration inhibitory factor gene (-173 G/C) polymorphism in the susceptibility and clinical expression of patients with Henoch-Schönlein purpura (HSP). HSP patients (n:139) and ethnically matched healthy controls (n:100) were genotyped by PCR-RFLP. Genotype analysis of both polymorphisms did not reveal a significant deviation from Hardy-Weinberg equilibrium in any group (p > 0.05). No significant difference was obtained in genotype distribution (p > 0.05) and allele frequencies (p > 0.05) between patients and controls. A statistically significant genotype-phenotype correlation was not obtained when HSP patients were stratified by the presence of certain systemic complications and the macrophage migration inhibitory factor gene (-173 G/C) polymorphism (p > 0.05). A significant risk was not observed in the subjects both with the GC+CC genotype (p = 0.06, OR: 0.5538, 95% CI: 0.2985-1.0274) and C allele (odds ratio: C vs. G: 1.799, 95% CI: 1.002-3.23, p = 0.05). Our findings suggest that MIF gene -173 G/C polymorphism is not associated with HSP in the present Turkish population.

Immune cell infiltrates in atypical teratoid/rhabdoid tumors

OBJECTIVE

Atypical teratoid/rhabdoid tumor (AT/RT) is a highly malignant tumor of the central nervous system. Its pathogenesis remains unknown. Like glioblastomas, AT/RTs contain brain cancer stem cells (CSCs) that suppress the immunity of patients and are resistant to conventional chemotherapy and radiation therapy. Considerable infiltration of immune cells, including macrophages/microglia, dendritic cells and T-cells, has been noted in glioblastomas, which correlates with poor prognosis. The present study examines the significance of infiltrating immune cells in four cases of AT/RT; including one associated with an autoimmune disease, Henoch-Schonlein purpura.

METHODS

Tumor tissues from four patients with AT/RT were analyzed and compared with those from four patients with glioblastomas. The frequency of immune cells, including CD68+, CD4+, and CD8+ cells, was assessed by scoring for statistical analysis.

RESULTS

The infiltration of immune cells was identified in the case of AT/RT associated with HSP and three other cases of infratentorial AT/RTs. Moderate infiltration of CD68+ macrophages/microglia and CD4+ cells was noted in AT/RTs with no significant difference from that in glioblastomas (p > 0.05). However, the infiltration of CD8+ T-cells was significantly higher in AT/RTs than that in glioblastomas (p < 0.05); CD4+/CD8+ ratio was significantly lower in AT/RTs than that in glioblastomas (p < 0.05). In addition, eosinophils were found in all AT/RTs, but not in glioblastomas.

CONCLUSIONS

These findings suggest an immune microenvironment of AT/RTs with more immune effectors than glioblastomas. Our observation contributes to understanding the growth environment of AT/RTs for which adjuvant immunotherapy may be potentially beneficial.

Circulating endothelial microparticles in children with Henoch-Schönlein purpura; preliminary results

The aim of this study was to investigate the levels of circulating endothelial microparticles (EMPs) in children with HSP and to determine whether there was a difference between patients with nephritis and those without nephritis. Twenty patients with HSP aged between 2.5 and 15 and 10 age-and sex-matched healthy controls were enrolled in the study. The HSP group was divided into two groups, including patients with nephritis (n = 9) and those without nephritis (n = 11). In all groups, circulating EMPs were enumerated by flow cytometry, after staining platelet-free plasma with PE-conjugated anti-CD144. At the same time, human umbilical vein endothelial cells (HUVEC) were incubated with the platelet-free plasma of patients with HSP and that of the control group. Then, circulating EMPs were counted in HUVEC supernatant incubated with the platelet-free plasma of patients and control groups, after staining the supernatant with PE-conjugated anti-CD146. Circulating EMPs were significantly higher in both the active and the remission period of the patient groups compared with the control subjects. In the patient group, there were no statistically significant differences in the level of circulating EMPs between patients with nephritis and those without nephritis. Both CD144 and 146+EMP in patients with HSP nephritis in the active period were substantially higher than in those remissions. CD144+EMP in the active period were substantially higher than in the remission period in patients without nephritis. We detected that circulating EMPs increased in patients with HSP in both active and remission periods. Although clinical and laboratory findings return to normal in the remission period, the increased circulating EMPs may show that the subclinical inflammatory process is continuous. We think that circulating EMPs could be used as a surrogate marker for subclinical inflammation in HSP.

Progress in pediatric vasculitis

PURPOSE OF REVIEW

To examine recent advances in the pathophysiology and therapy of pediatric vasculitis.

RECENT FINDINGS

The past 2 years have been marked by significant progress in extending novel techniques to the investigation of the two most common pediatric vasculitis syndromes, Henoch-Schonlein purpura and Kawasaki disease. Study of other vasculitides, such as Wegener granulomatosis, Churg-Strauss syndrome, and microscopic polyangiitis, is impeded by the small number of pediatric patients. Nonetheless, national and international registries are beginning to provide the foundation for generation of testable hypotheses regarding pathogenesis and optimal treatment. Thus, recent data from the study of children suggest that disorders in the control of inflammation, such as those that underlie familial Mediterranean fever and other autoinflammatory diseases, may predispose to vasculitis. Improved knowledge of mechanisms of disease, in turn, should pave the way for more targeted, effective, and tolerable therapies for children with systemic vasculitis.

SUMMARY

International collaboration to study rare disorders such as pediatric vasculitis are demonstrating disorders of inflammatory regulation that predispose to these diseases and may point toward new treatment approaches.