No abstract

BackgroundTo explore the effects of extracellular histones released by activated neutrophils on systemic-onset juvenile idiopathic arthritis (SoJIA), and to study the change of serum histone level between the active and remissive stage of SoJIA, then to clarify the role of serum histone in the pathogenesis of SoJIA.MethodsTwenty-six patients with SoJIA were recruited, and clinical informations were collected, and the serum histone was detected by ELISA. While neutrophils from normal children were incubated with the serum from the patients with SoJIA, also including incubated with FeCL3 and histone, the extracellular histone was detected, respectively; heparin was added to the above-mentioned groups to observe the changes of extracellular histone levels. The proportions of neutrophils, which released NETs, were calculated by confocal microscope.ResultsThe levels of serum histones in active SoJIA group (0.90 ± 0.90) were significantly higher than in remissive SoJIA group (0.17 ± 0.10) (P = 0.0009), and also higher than in control group (0.14 ± 0.09) (P = 0.246). Histone affects on clinical manifestations (including fever, rash, joint pain, liver and spleen enlargement, and serositis), except for joint pain. The proportions of neutrophils releasing NETs, that neutrophils were incubated with the serum from active SoJIA group, were 31.93% significantly higher than 12.32% from remissive SoJIA group (P < 0.0001). The proportions of neutrophils releasing NETs, that neutrophils were incubated with different concentration FeCl3 or with different concentration histones respectively, were positively correlated with the concentration of incubation; while heparins were added, NETs from neutrophils could be reduced effectively.ConclusionsThe level of serum histone is positively correlated with the activity of SoJIA. Serum histone may be from NETs, which were released by activated neutrophils. Free iron can activate neutrophils to produce NETs, which may release histones, and histones can further promote NETs to be released, that results in a positive feedback loop of histones, and that may be one of the pathogenesis of acute SoJIA or MAS secondary to SoJIA. Histones maybe play one of important roles in the pathogenesis of SoJIA. Heparin can act on histones to prevent histone-induced inflammation.Trial registrationChiCTR-OOC-15006228. Registered 9 April 2015, http://www.chictr.org.cn/showproj.aspx?proj=10752Electronic supplementary materialThe online version of this article (10.1186/s13052-019-0605-2) contains supplementary material, which is available to authorized users.

Background. Henoch-Schönlein purpura (HSP) is a systemic small-vessel vasculitis caused by environmental and inherent factors. Although recent research has advanced our understanding of the role of genetic susceptibility in HSP, there are still significant gaps in our knowledge. Objectives. In this study, we aimed to explore some susceptibility genes likely associated with HSP. Material and methods. Three DNA samples from a family with HSP were used to perform whole exome sequencing with Illumina Hiseq 2500 high-throughput sequencing. The relevant single nucleotide variants (SNVs) were screened according to specific filter conditions and the screened SNVs were then verified with Sanger sequencing. The Sanger sequencing results were further screened according to available literature. Finally, candidate genes were validated in 92 samples from children with HSP, and also in 1 child with HSP from HSP family, using the polymerase chain reaction technique (PCR). Results. Our analysis revealed that the MIF gene and the MGAT5 gene related to immunity remained after screening. Among the 93 children with HSP, there were 3 patients with MIF mutations and 2 patients with MGAT5 mutations. Conclusions. Our findings are helpful for providing new methods and ideas for understanding the pathogenesis of HSP by detecting and analyzing gene mutations at the whole-exome level including multi-generation sequencing. MIF and MGAT5 may be new susceptibility loci for HSP, but their roles in the pathogenesis of HSP are worthy of further study.

The pandemic Coronavirus Disease 2019 (COVID-19) causes noticeable morbidity and mortality worldwide. In addition to vaccine and antiviral drug therapy, the use of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) neutralizing antibodies for treatment purposes is a viable alternative. In this study, we aimed to profile the humoral responses and identify neutralizing antibodies against SARS-CoV-2 using high-throughput single-cell sequencing that tailored to B cell receptor sequencing. From two convalescent patients with high serum titer against SARS-COV-2, we identified seven antibodies specifically binding to SARS-CoV-2. Among these, the most potent antibody, P4A1 was demonstrated to block the binding of spike protein to its receptor angiotensin-converting enzyme 2 (ACE2), and prevent the viral infection in neutralization assays with pseudovirus as well as live virus at nM to sub-nM range. Moreover, antibody P4A1 can also bind strongly to spike protein with N354D/D364Y, R408I, W436R, V367F or D614G mutations respectively, suggesting that the antibody alone or in combination with other antibodies that recognize different variations of SARS-CoV-2, may provide a broad spectrum therapeutic option for COVID-19 patients. Authors Lisu Huang, Bingqing Shen, Yu Guo, and Shu Shen contributed equally to this work.