Oestrogen up‐regulates interleukin‐21 production by CD4+ T lymphocytes in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease in which abnormal immune responses are mediated by tissue‐binding autoantibodies and immune complex deposition. Because most SLE patients are women of child‐bearing age, oestrogen has been suggested to play an important role in SLE pathogenesis. One proposed role is to induce B‐cell activation, culminating in increased autoantibody production. Interleukin‐21 (IL‐21) has been shown to be crucial in the differentiation of activated B cells into plasma cells. We therefore hypothesized that oestrogen up‐regulates IL‐21 production and induces subsequent B‐cell activation in SLE patients. Peripheral blood was obtained from 22 SLE patients and 16 healthy controls. Expression levels of IL‐21 and its receptor in serum, peripheral blood mononuclear cells, and CD4⁺ T cells were higher in SLE patients than in healthy controls. Exposure of CD4⁺ T cells from SLE patients to 17β‐oestradiol led to a dose‐ and time‐dependent increase in IL‐21 expression, which was abolished in the presence of mitogen‐activated protein kinase (MAPK) (MAPK kinase, p38, Jun N‐terminal kinase) inhibitors. B cells from healthy controls showed increased antibody production when they were co‐cultured with oestrogen‐treated CD4⁺ T cells from SLE patients. Treatment with IL‐21 antibody abrogated the increased antibody production of the co‐culture systems. This study revealed the association between oestrogen and IL‐21 in SLE patients. Oestrogen up‐regulates IL‐21 expression of CD4⁺ T cells via MAPK‐dependent pathways in SLE patients, which in turn induces increased antibody production by B cells.     

Maternal antibodies from mothers of children with autism alter brain growth and social behavior development in the rhesus monkey

Antibodies directed against fetal brain proteins of 37 and 73 kDa molecular weight are found in approximately 12% of mothers who have children with autism spectrum disorder (ASD), but not in mothers of typically developing children. This finding has raised the possibility that these immunoglobulin G (IgG) class antibodies cross the placenta during pregnancy and impact brain development, leading to one form of ASD. We evaluated the pathogenic potential of these antibodies by using a nonhuman primate model. IgG was isolated from mothers of children with ASD (IgG-ASD) and of typically developing children (IgG-CON). The purified IgG was administered to two groups of female rhesus monkeys (IgG-ASD; n=8 and IgG-CON; n=8) during the first and second trimesters of pregnancy. Another control group of pregnant monkeys (n=8) was untreated. Brain and behavioral development of the offspring were assessed for 2 years. Behavioral differences were first detected when the macaque mothers responded to their IgG-ASD offspring with heightened protectiveness during early development. As they matured, IgG-ASD offspring consistently deviated from species-typical social norms by more frequently approaching familiar peers. The increased approach was not reciprocated and did not lead to sustained social interactions. Even more striking, IgG-ASD offspring displayed inappropriate approach behavior to unfamiliar peers, clearly deviating from normal macaque social behavior. Longitudinal magnetic resonance imaging analyses revealed that male IgG-ASD offspring had enlarged brain volume compared with controls. White matter volume increases appeared to be driving the brain differences in the IgG-ASD offspring and these differences were most pronounced in the frontal lobes.     

不同胰岛自身抗体阳性1型糖尿病临床特征分析

目的探讨单独或合并锌转运体8自身抗体(ZnT8A)、谷氨酸脱羧酶抗体(GADA)及蛋白酪氨酸磷酸酶抗体(IA-2A)阳性患者的1型糖尿病(T1DM)患者临床特征。方法采用放射配体检测法检测中南大学湘雅二医院1999—2009年收治的539例T1DM患者的ZnT8A、GADA及IA-2A,并将其分成三个亚组进行比较。结果(1)单一ZnT8A阳性组较抗体阴性组病程更长,胰岛素用量更大,收缩压更低,合并代谢综合征比例更少。单一ZnT8A阳性组较单一GADA阳性组BMI、WHR及空腹C肽值更高(P<0.05),而糖化血红蛋白水平更低(P<0.05);(2)多个抗体阳性组起病年龄显著低于抗体阴性组(P<0.05);1个抗体阳性患者的空腹C肽及餐后2 h C肽显著低于抗体阴性组(P<0.05);3个抗体阳性患者较1个抗体阳性患者的起病年龄更小(P<0.01),BMI更低(P<0.05),病程更短(P<0.05)。(3)合并任意两种抗体阳性中"GADA阳性与IA-2A阳性"组餐后C肽最低(P<0.01),空腹C肽也较低,但差异无统计学意义(P>0.05)。结论单独或合并ZnT8A,GADA及IA-2A的T1DM临床特征分析对临床具有重要的指导意义。     

Pre‐transplant phospholipase A2 receptor autoantibody concentration is associated with clinically significant recurrence of membranous nephropathy post‐kidney transplantation

Previous studies that have assessed the association of pre‐transplant antiphospholipase A2 receptor autoantibody (PLA2R‐Ab) concentration with a recurrence of membranous nephropathy (rMN) post‐kidney transplant have yielded variable results. We tested 16 consecutive transplant patients with a history of iMN for pre‐transplant PLA2R‐Ab. Enzyme‐linked immunosorbent assay titers (Euroimmun, NJ, USA) >14 RU/mL were considered positive. A receiver operating characteristic (ROC) analysis was performed after combining data from Quintana et al. (n = 21; Transplantation February 2015) to determine a PLA2R‐Ab concentration which could predict rMN. Six of 16 (37%) patients had biopsy‐proven rMN at a median of 3.2 yr post‐transplant. Of these, five of six (83%) had a positive PLA2R‐Ab pre‐transplant with a median of 82 RU/mL (range = 31–1500). The only patient who had rMN with negative PLA2R‐Ab was later diagnosed with B‐cell lymphoma. One hundred percent (n = 10) of patients with no evidence of rMN (median follow‐up = five yr) had negative pre‐transplant PLA2R‐Ab. In a combined ROC analysis (n = 37), a pre‐transplant PLA2R‐Ab > 29 RU/mL predicted rMN with a sensitivity of 85% and a specificity of 92%. Pre‐transplant PLA2R‐Ab could be a useful tool for the prediction of rMN. Patients with rMN in the absence of PLA2R‐Ab should be screened for occult malignancy and/or alternate antigens.     

女性不孕症患者血清及宫颈黏液中自身抗体检测对病情的评估价值

目的  分析女性不孕症患者血清及宫颈黏液中自身抗体检测对病情的评估价值。方法  选取2012年7月-2014年7月间至该院接受检查的女性不孕患者138例作为观察组对象。另取同期在该院因宫颈炎症接受检查的已育女性106例作为对照组。比较两组研究对象的血清及宫颈黏液自身抗体水平、外周血调解性T细胞（Treg）水平,进一步分析观察组患者中自身抗体与Treg水平的相关性。结果  ①观察组患者的血清及宫颈黏液中抗精子抗体（AsAb）、抗卵巢抗体（AoAb）、抗人绒毛膜促性腺激素（AhCGAb）、抗子宫内膜抗体（EMAb）、甲状腺自身抗体（ATA）、抗-β-2糖蛋白1抗体（α-β-2GP1）水平高于对照组女性（P <0.05）;②观察组患者的外周血Treg水平低于对照组（P <0.05）;③不孕症女性血清及宫颈黏液中的AsAb、AoAb、AhCGAb、EMAb、ATA、α-β-2GP1等自身抗体水平与外周血Treg水平呈负相关（P <0.05）。结论  女性不孕症患者血清及宫颈黏液中自身抗体水平大幅上升,与患者的疾病发生发展以及病情严重程度均关系密切,是临床诊断及指导治疗的理想指标。

     

Longitudinal changes in epitope recognition of autoantibodies against glutamate decarboxylase 65 (GAD65Ab) in prediabetic adults developing diabetes

We analysed the beta cell-specific autoimmunity reflected in autoantibodies to the smaller isoform of glutamate decarboxylase (GAD65Ab) in the prediabetic period of GAD65Ab-positive healthy adults who developed Type 2 diabetes (T2D) during a follow-up period of 10 years. We found that of the adults that tested GAD65Ab-positive at baseline (n=25), six developed T2D and one developed Type 1 diabetes (T1D). Of the subjects that tested GAD65Ab-negative at baseline (n=2209), 81 developed T2D, one developed T1D and four developed unclassified diabetes, indicating that the risk for GAD65Ab-positive healthy adults to develop diabetes is increased sixfold. The GAD65Ab epitopes were characterized in a competition radioligand binding assay using recombinant Fab derived of GAD65-specific monoclonal antibodies. We observed that the GAD65Ab epitope specificities in the prediabetic period changed dynamically. Specifically, the binding to a middle and a C-terminal epitope increased during the follow-up period (P=0 x 03), causing a significant increase in the number of epitopes recognized (P=0 x 03). These findings are similar to previous observations of dynamic changes in the prediabetic period of schoolchildren at high risk for T1D development. However, the character of the epitopes differs between the two populations, suggesting differences in the beta cell-specific autoimmune response in the prediabetic period of patients with latent autoimmune diabetes in adults (LADA) and T1D.     

Affinity maturation of immunoglobulin A anti-tissue transglutaminase autoantibodies during development of coeliac disease

Coeliac disease (CD) is an immune-mediated enteropathy triggered by ingestion of wheat gluten and related cereals in genetically predisposed individuals. Circulating immunoglobulin A (IgA) class autoantibodies against tissue transglutaminase (IgA-TGA) are highly specific and sensitive serological markers for CD, which is ultimately confirmed by duodenal biopsy. Although CD is considered a life-long disorder, transient or fluctuating IgA-TGA seropositivity has been observed in asymptomatic individuals on a gluten-containing diet. We set out to explore possible differences in the maturation of IgA-TGA avidity between individuals progressing to CD and subjects remaining healthy despite occasional expression of autoantibodies. We developed a time-resolved fluorometric IgA-TGA assay based on human recombinant tissue transglutaminase (tTG), and further modified the method to also measure urea-dependent avidity of the autoantibodies. We measured the autoantibody titres and avidities of sequential serum samples from 10 children developing CD and 10 children presenting transient or fluctuating autoantibodies. Both the initial titres at seroconversion and peak values of transient/fluctuating IgA-TGA were significantly lower than corresponding autoantibody titres in samples drawn from individuals with progressing CD (P = 0.004 and P = 0.0002, respectively). However, there were no statistically significant differences in the initial or peak avidity index values between the two groups of children. The avidity index values increased during the follow-up period (P = 0.013 for both groups) with no significant difference in the rate of avidity maturation between children with transient/fluctuating IgA-TGA and children developing CD. According to our results, high autoantibody titres have a higher predictive value than avidity maturation of TGA-IgA in screening for CD.     

Extracellular vesicles derived from injured vascular tissue promote the formation of tertiary lymphoid structures in vascular allografts

Tertiary lymphoid structures (TLS) accumulate at sites of chronic injury where they function as an ectopic germinal center, fostering local autoimmune responses. Vascular injury leads to the release of endothelial‐derived apoptotic exosome‐like vesicles (ApoExo) that contribute to rejection in transplanted organs. The purpose of the study was to evaluate the impact of ApoExo on TLS formation in a model of vascular allograft rejection. Mice transplanted with an allogeneic aortic transplant were injected with ApoExo. The formation of TLS was significantly increased by ApoExo injection along with vascular remodeling and increased levels of antinuclear antibodies and anti‐perlecan/LG3 autoantibodies. ApoExo also enhanced allograft infiltration by γδT17 cells. Recipients deficient in γδT cells showed reduced TLS formation and lower autoantibodies levels following ApoExo injection. ApoExo are characterized by proteasome activity, which can be blocked by bortezomib. Bortezomib treated ApoExo reduced the recruitment of γδT17 cells to the allograft, lowered TLS formation, and reduced autoantibody production. This study identifies vascular injury‐derived extracellular vesicles (ApoExo), as initiators of TLS formation and demonstrates the pivotal role of γδT17 in coordinating TLS formation and autoantibody production. Finally, our results suggest proteasome inhibition with bortezomib as a potential option for controlling TLS formation in rejected allografts.     

Aptamer BC 007’s Affinity to Specific and Less-Specific Anti-SARS-CoV-2 Neutralizing Antibodies

COVID-19 is a pandemic respiratory disease that is caused by the highly infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Anti-SARS-CoV-2 antibodies are essential weapons that a patient with COVID-19 has to combat the disease. When now repurposing a drug, namely an aptamer that interacts with SARS-CoV-2 proteins for COVID-19 treatment (BC 007), which is, however, a neutralizer of pathogenic autoantibodies in its original indication, the possibility of also binding and neutralizing anti-SARS-CoV-2 antibodies must be considered. Here, the highly specific virus-neutralizing antibodies have to be distinguished from the ones that also show cross-reactivity to tissues. The last-mentioned could be the origin of the widely reported SARS-CoV-2-induced autoimmunity, which should also become a target of therapy. We, therefore, used enzyme-linked immunosorbent assay (ELISA) technology to assess the binding of well-characterized publicly accessible anti-SARS-CoV-2 antibodies (CV07-209 and CV07-270) with BC 007. Nuclear magnetic resonance spectroscopy, isothermal calorimetric titration, and circular dichroism spectroscopy were additionally used to test the binding of BC 007 to DNA-binding sequence segments of these antibodies. BC 007 did not bind to the highly specific neutralizing anti-SARS-CoV-2 antibody but did bind to the less specific one. This, however, was a lot less compared to an autoantibody of its original indication (14.2%, range 11.0–21.5%). It was also interesting to see that the less-specific anti-SARS-CoV-2 antibody also showed a high background signal in the ELISA (binding on NeutrAvidin-coated or activated but noncoated plastic plate). These initial experiments suggest that the risk of binding and neutralizing highly specific anti-SARS CoV-2 antibodies by BC 007 should be low.