Aberrant autoantibody production is characteristic of systemic lupus erythematosus (SLE), but follicular regulatory T (TFR) cells potentially can suppress this abnormality. We investigate functional changes in TFR cells from SLE patients. Circulating TFR cells were collected from 19 SLE patients and 14 healthy controls (HC) to compare molecular expression and in vitro suppressive capacity of follicular helper T (TFH) cell proliferation. To reveal the stability of Foxp3 in TFR, pyrosequencing of conserved non-coding sequence (CNS) 2 at the Foxp3 gene locus was performed. We then tested IL-2 in SLE-TFR cells to check restoration of suppressor function. Programmed death-1 (PD-1) expression in SLE-TFR cells was positively correlated with anti-DNA antibody levels and disease activity. These cells had impaired suppressive function for TFH cells with decreased expression of suppression mediators forkhead box p3 (Foxp3), cytotoxic T-lymphocyte antigen 4 (CTLA4), and IL-2 receptor alpha (IL2Rα). Pyrosequencing identified hyper-methylation in CNS2 region of SLE-TFR cells comparing to HC. With In vitro IL-2 stimulation, PD-1 expression of TFR cells significantly decreased along with increased expression of Foxp3 and CTLA-4, especially in low-dose. Thus, SLE-TFR cells have functionally defective to TFH suppression, but low-dose IL-2 therapy might be useful to restore this ability.

Background: Cladribine (CdA), an oral prodrug approved for the treatment of relapsing multiple sclerosis, selectively depletes lymphocytes. CdA passes the blood-brain barrier suggesting a potential effect on CNS resident cells. Objective: We examined, if CdA modifies the phenotype and function of naïve and activated primary mouse microglia, when applied in different concentrations including 0.1-1 µM that putatively overlaps human CSF concentrations. Methods: Primary microglia cultures without stimulation or in the presence of proinflammatory lipopolysaccharide (LPS) or anti-inflammatory IL-4 were co-treated with different concentrations of CdA for 24 hours. Viability was assessed by MTT assay. Phagocytotic ability and morphology were examined by flow cytometry, and random migration by IncuCyte Zoom and TrackMate. Change in gene expression was examined by qPCR, and protein secretion by Meso Scale Discovery. Results: LPS and IL-4 upregulated deoxycytidine kinase (DCK) expression. Only activated microglia were affected by CdA, and this was unrelated to viability. CdA 0.1-1 µM significantly reduced granularity, phagocytotic ability and random migration of activated microglia. CdA 10 µM increased the IL-4-induced gene expression of Arg1 and LPS-induced expression of IL-1beta, TNF, iNOS, and Arg1, but protein secretion remained unaffected. CdA 10 µM potentiated the increased expression of anti-inflammatory TNFR2 but not TNFR1 induced by LPS. Conclusion: Microglia acquire a less activated phenotype when treated with 0.1–1 µM CdA that putatively overlaps human CSF concentrations. This may be related to the upregulated gene expression of DCK upon activation and suggests a potential alternative mechanism of CdA with direct effect on CNS resident cells.

Allergic sensitization is commonly assessed in patients by performing the skin prick test (SPT) or determining specific IgE levels in blood samples with the ImmunoCAP assay, which measures each allergen and sample separately. This paper explores the possibility to investigate respiratory allergies with a high throughput method, the Meso Scale Discovery (MSD) multiplex immunoassay, measuring IgE levels in low volumes of blood. The MSD multiplex immunoassay, developed and optimized with standards and allergens from Radim, was validated against the SPT and the ImmunoCAP assay. For 18 adults (15 respiratory allergy patients and 3 controls), blood collection and the SPT were performed within the same hour. Pearson correlations and Bland-Altman analysis showed high comparability of the MSD multiplex immunoassay and the ImmunoCAP assay, except for house dust mite. The sensitivity of the MSD multiplexed assay was ≥75% for most allergens compared to the SPT and ImmunoCAP assay. Additionally, the specificity of the MSD multiplex immunoassay was ≥80% - the majority showing 100% specificity. Only the rye allergen had a low specificity when compared to the SPT, probably due to cross-reactivity. The reproducibility of the MSD multiplex immunoassay, assessed as intra- and inter-assay reproducibility and biological variability between different sampling moments, showed significantly high correlations (r=0.943-1) for all tested subjects (apart from subject 13; r=0.65-0.99). The MSD multiplex immunoassay is a reliable method to detect specific IgE levels against respiratory allergens in a multiplexed and high throughput way, using blood samples as small as from a finger prick.

Though the pathogenesis of acute myeloid leukemia (AML) is still unknown, accumulating evidence has revealed that immune response plays a vital part in the pathogenesis. Here, we investigated the involvement of 24 single-nucleotide polymorphisms (SNPs) of immuno-related genes, including cytokines (IL2, IL4, IL9, IL-12A, IL-22, IFNG, and TGFB1), transcriptional regulatory genes (TBX21, STAT1, STAT3, STAT5B, STAT6, GATA3, FOXP3, and IRF4), and others (IL2RA IL6R NFKBIA), in 269 AML inpatients and 200 healthy controls. Furthermore, we analyzed the relationship between the SNPs and clinical characteristics. Immuno-related SNP genotyping was performed on the Sequenom MassARRAY iPLEX platform. All the SNPs in healthy controls were consistent with Hardy–Weinberg equilibrium. All final p values were adjusted by Bonferroni multiple testing. Our results showed that IL-22 (rs2227491) was significantly associated with the white blood cell (WBC) counts. STAT5B (rs6503691) showed a close relationship with the recurrent genetic abnormalities in patients with AML. We verified the negatively independent effect of age and risk of cytogenetics on overall survival (OS). More importantly, the GG genotype of IL-12A (rs6887695) showed a negative impact on AML prognosis independently. Furthermore, the relative expression of IL-12 was decreased in GG genotype, no matter under codominant or recessive model. However, no correlation was observed between the SNPs mentioned above and disease susceptibility, risk stratification, and survival. Our findings suggest that immuno-related gene polymorphisms are associated with prognosis in AML, which may perform as novel inspection targets for AML patients.

Although increasing evidence demonstrates the association between intestinal dysbiosis and pancreatic diseases, such as chronic pancreatitis and pancreatic cancer, it remains largely unknown whether intestinal dysbiosis is involved in the immunopathogenesis of autoimmune pancreatitis (AIP). Recently, we found that intestinal dysbiosis mediates experimental AIP via the activation of plasmacytoid dendritic cells (pDCs), which can produce IFN-α and IL-33. However, candidate pathobionts for type 1 AIP have not been identified. In this study, we tried to identify pathobionts associated with type 1 AIP. Fecal samples were obtained from type 1 AIP patients before and after prednisolone (PSL) treatment and subjected to 16S ribosomal RNA sequencing to evaluate the composition of intestinal bacteria. Induction of remission by PSL was associated with the complete disappearance of Klebsiella species from feces, in two of the three analyzed patients with type 1 AIP. To assess the pathogenicity of Klebsiella species, mild experimental AIP was induced in MRL/MpJ mice by repeated injections of 10 μg of polyinosinic-polycytidylic acid (poly (I:C)) in combination with oral administration of heat-killed Klebsiella pneumoniae. The AIP pathology score was significantly higher in MRL/MpJ mice that received both oral administration of heat-killed K. pneumoniae and intraperitoneal injections of poly (I:C) than in those administered with either agent alone. Pancreatic accumulation of pDCs capable of producing large amounts of IFN-α and IL-33 was also significantly higher in mice that received both treatments. These data suggest that intestinal colonization by K. pneumoniae may play a pathogenic role in AIP.

Background. Anti-citrullinated protein/peptide antibodies (ACPA) play important roles in the pathogenesis of rheumatoid arthritis (RA). ACPA-positive (ACPA+) and ACPA-negative (ACPA-) RA were suggested to be different disease subsets with distinct differences in genetic variation and clinical outcomes. The aims of the present study were to compare gene expression profiles in ACPA+ and ACPA- RA and identify novel candidate gene signatures that might serve as therapeutic targets. Methods. Comprehensive transcriptome analysis of peripheral blood mononuclear cells (PBMCs) from ACPA+ and ACPA- RA patients, and healthy controls was performed via RNA sequencing. A validation cohort was used to further investigate differentially expressed genes via PCR and ELISA. Spearman’s correlation test was used to evaluate the correlation of differentially expressed genes and the clinical and laboratory data of the patients. The role of differentially expressed genes in osteoclastogenesis was further investigated. Results. Expression of C-X-C motif chemokine ligand 2 (CXCL2) was significantly increased in ACPA+ RA than in ACPA- RA, which was validated in PBMCs and serum. CXCL2 promoted the migration of CD14+ monocytes and increased osteoclastogenesis in RA patients. RAW264.7 macrophages were used to investigate specific mechanisms, and the results suggested that CXCL2 stimulated osteoclastogenesis via ERK MAPK and NFκB pathways. Conclusion. CXCL2 was highly expressed in ACPA+ RA than in ACPA- RA. CXCL2 promoted osteoclastogenesis and was related to bone erosion in RA, which suggest that the blockade of CXCL2 might be a novel strategy for the treatment of RA.

Background: Pulmonary sarcoidosis is characterized by an exaggerated CD4+ T-cell response and formation of non-necrotizing granulomas. Tumour necrosis factor α (TNF-α) is regarded as crucial for granuloma formation and TNF-α inhibitors offer a 3rd line treatment option for patients not responding to conventional treatment. However, not all patients benefit from treatment, and an optimal dose and treatment duration have not been established. Insight into the influence of TNF-α inhibitors on lung immune cells may provide clues to what drives inflammation in sarcoidosis and improve our understanding of treatment outcomes. Objectives: To evaluate effects of treatment with the TNF- α inhibitor infliximab on lung immune cells and clinical features of the patients. Methods: Thirteen patients with sarcoidosis refractory to conventional treatment were assessed with bronchoalveolar lavage (BAL), spirometry and CT scan in close adjacent to start of infliximab treatment. These investigations were repeated after six months of treatment. Results: Treatment with TNF- α inhibitor infliximab was well tolerated with no adverse events, except for one patient who developed a probable adverse event with liver toxicity. Ten patients were classified as responders, having a reduced CD4/CD8 ratio, a decreased percentage of CD4+ T-cells expressing the activation marker CD69 and number of mast cells (p<0.05 for all). The percentage of T regulatory cells (Tregs), defined as FoxP3+ CD4+ T-cells decreased in most patients. Conclusions: Six months of infliximab treatment in patients with sarcoidosis led to signs of decreased CD4+ T-cell alveolitis and decreased mastocytosis in the lungs of responders.

Follicular T helper (Tfh) and regulatory (Tfreg) cells are distinct subsets of CD4+T lymphocytes, regulating humoral immune responses in the germinal center. Dysregulated Tfh and Tfreg cells are believed to associate with autoimmunity. Here, we evaluated the frequencies of circulating CXCR5+PD-1+ Tfh (cTfh) and CXCR5+PD-1+FoxP3+CD25+ Tfreg (cTfreg) cells, and their corresponding cytokines from the peripheral blood mononuclear cells of 20 patients with relapsing-remitting multiple sclerosis (MS) and 12 age- and sex-matched healthy controls (HC). Subsets of cTfh cells by Th1 and Th17 related surface markers (CXCR3 and CCR6) were also evaluated. We found the frequency of cTfh cells was significantly higher in MS patients compared to HC (p=0.002). Conversely, cTfreg cells were downregulated in MS patients (p<0.0001). IL-21 producing cTfh cells were significantly increased in MS patients (p=0.003), while IL-10 secreting cTfreg cells were decreased in MS compared to HC (p=0.02). Among cTfh cells, cTfh17.1 cells were major subtypes that were significantly increased in MS compared to HC (p=0.002) and the frequency of IL-21 secreting cells were highest. These results suggest that an imbalanced distribution of cTfh and cTfreg exist in MS, which contributes to reciprocally altered IL-21 and IL-10 production.

Follicular helper T cells (Tfh) cells are generally considered critical in secondary lymphoid tissues; however, they are also identified in the circulation and in tertiary lymphoid structures in chronic inflammation. Gingival tissues with periodontitis reflect chronic inflammation so genomic footprints of Tfh cells should occur in these tissues and may differ related to aging effects. Methods: Macaca mulatta monkeys were used in a model of ligature-induced periodontitis [adult group (12-23 years of age); young group (3-7 years)]. Gingival tissue and subgingival microbiome samples were obtained at matched healthy sites, sites during ligature-induced disease, and in samples after clinical resolution. Microarray analysis examined Tfh genes (n=40) and the microbiome samples were examined using 16S MiSeq. Results: An apparent increase in the major transcription factor of Tfh cells, BCL6, was found with disease in both adult and young animals, while the master transcription markers of other T cell subsets were either decreased or showed minimal change. A number of the Tfh related genes, including surface receptors, secreted products and transcription factors were also significantly increased during disease. Unique microbial complexes showed patterns of interactions with Tfh genes that differed in health and disease. Conclusions: An increase in Tfh cell responsiveness occurred later in the progression of periodontitis, affected by age and strongly related to specific microbial complexes. The capacity of gingival Tfh cells to contribute to localized B cell activation and active antibody responses, including affinity maturation may be critical for controlling periodontal lesions and contributing to limiting and/or resolving the lesions.

Autoimmune neutropenia (AIN) in childhood is characterized by chronic neutropenia and positivity for antineutrophil antibodies, resulting in the excessive destruction of neutrophils. In this study, we investigated the involvement of regulatory T cells (Tregs) in the pathogenesis of AIN in childhood. Tregs have been classified into three subpopulations based on the expressions of CD45RA and FOXP3: resting Tregs, activated Tregs, and non-suppressive Tregs. The frequency of activated Tregs (CD4+CD25+FOXP3highCD45RA− T cells) as well as that of total Tregs (CD4+CD25+FOXP3+ T cells) in peripheral blood was significantly decreased in patients with AIN. Analysis of the T cell receptor (TCR)-Vβ repertoire of CD4+ T cells revealed skewed usages in patients with AIN compared with that observed in age-matched control subjects. Regarding T cell subsets, the use of four of 24 TCR-Vβ families in Tregs and one in conventional T cells were increased in patients with AIN. The number of patients with AIN who showed skewed usages of TCR-Vβ family in conventional and Tregs was significantly higher than that reported in control subjects. When the preference between Tregs and conventional T cells in each TCR-Vβ family was individually compared, different use was prominently observed in the TCR-Vβ 9 family in patients with AIN. These results suggest that the quantitative abnormalities of Tregs and the skew of the TCR-Vβ repertoire in CD4+ T cells, including Tregs and conventional T cells, may be related to autoantibody production through a human neutrophil antigen-reactive T cell clone.

Backgroud: A long-term hepatic inflammatory response is a risk factor for liver cancer initiation and progression. Interleukin (IL)-35 is the newest member of the IL-12 cytokine family, and has been reported to play an essential role in the immunosuppressive liver microenvironment. Herein we focus on the expression profiles of IL-35 in hepatocellular carcinoma (HCC) and the effect on local immune status. Methods: HCC transcriptome array data were downloaded from Gene Expression Omnibus. The bioinformatics analysis was performed by the BRB array tools and online Ingenuity Pathway Analysis software. The serum IL-35 level was detected by AimPlet bead-based immunoassay. In situ IL-35 expression detection was performed by immunohistochemical staining and western blot. Results: Our results showed that there were large amounts of IL-35 expressed in HCC serum and tumor tissues. IL-35 expression affects the transcript of thousands of genes, most of which correlated with T-cell immunity. This study proved that enhancement of regulatory T cells (Tregs) and impairment of cytolytic T cells are prominent effects of IL-35. Conclusions: Elevated IL-35 played critical roles in HCC patients through affecting the balance between Tregs and cytotoxic T cells. Dissection of the precise targets and the underlying molecular mechanisms will lead to alternative treatments for HCC patients.

Natural Killer (NK) cell functions are regulated by diverse inhibitory and activating receptors including Killer cell Immunoglobulin-like receptors (KIR) which interact with HLA class I molecules. Some KIR/HLA genetic combinations were reported associated with spontaneous clearance (SC) of hepatitis C virus (HCV) but with discordant results, possibly reflecting KIR and/or HLA gene polymorphism according to populations. KIR/HLA genetic combinations associated with both an exhaustive NK and T cell repertoire were investigated in a cohort of HIV-HCV co-infected individuals with either SC (n=68) or chronic infection (CI, n=163) compared to uninfected blood donors (Ctrl, n=100). Multivariate analysis showed that the HLA C2C2 environment was associated with SC only in European HIV-HCV co-infected individuals (OR=4.30[1.57-12.25], p=0.005). KIR2D+ NK cell repertoire and potential of degranulation of KIR2DL1/S1+ NK cells were similar in SC European cohort compared to uninfected individuals. In contrast, decreased frequencies of KIR2DS1+ and KIR2DL2+ NK cells were detected in CI group of Europeans compared to SC and a decreased frequency of KIR2DL1/S1+ NK cells compared to controls. On the T cell side, higher frequencies of DNAM-1+ and CD57+ T cells were observed in SC in comparison to controls. Interestingly, SC subjects emphasized increased frequencies of KIR2DL2/L3/S2+ T cells compared to CI subjects. Our study underlines that the C2 environment may activate efficient KIR2DL1+ NK cells in viral context and maintain KIR2DL2/L3/S2+ mature T cell response in the absence of KIR2DL2 engagement with its cognate ligands in SC group of HCV-HIV co-infected European patients.

Background NOD-like receptor pyrin 7 (NLRP7) has been identified as the major gene responsible for the recurrent hydatidiform mole (RHM). The immunological role of NLRP7 mutation in HM patients has not been conclusively demonstrated. Hence, we aim to demonstrate this role in our study. Methods We followed 12 new patients with NLRP7 nonsynonymous variations (NSVs) from date to date. Peripheral blood mononuclear cells (PBMCs) were collected from patients with and without NLRP7 mutation, separately. Supernatant IL-1β secretion, intracellular pro-IL-1β and mature-IL-1β expressions were measured after 24h lipopolysaccharide (LPS) stimulation. Plasmids with corresponding NSVs were generated to evaluate the ability of processing pro-IL-1β into mature-IL-1β in vitro. Results Homozygous or compound heterozygous NLRP7 mutation secreted less IL-1β in root of abnormal intracellular pro-IL-1β or mature-IL-1β according to different domain defective. Plasmids with NSVs could also affect processing or/and trafficking together with caspase-1 and apoptosis-associated speck-like protein (ASC). Conclusion Inflammasome related NLRP7 mutation is a potential mechanism of RHM.

Tuberculosis kills more people than any other single infectious disease globally. Despite decades of research, there is no vaccine to prevent TB transmission. Bacille Calmette-Guerin (BCG) vaccine developed a century ago has little effect on pulmonary TB and does not control transmission. Lack of an effective vaccine emanates from lack of knowledge on correlates of protective immunity on which to base vaccine design and development. However, some household contacts who are extensively exposed to Mtb infection remain persistently negative to tuberculin skin test and interferon-gamma assay. These individuals called “resisters” clear Mtb infection early before the development of acquired immunity. The immunological basis of early Mtb clearance is yet to be established, however, innate lymphocytes such as monocytes/macrophages, dendritic cells, neutrophils and natural killer cells, and innate like T cells such as mucosal associated invariant T cells, invariant natural killer T cells and gamma-delta (γδ) T cells have been implicated in this early protection. One of the cells that has attracted increasing attention in recent years, in protection against Mtb is the natural killer cell. Emerging data from animal and epidemiological studies indicate that NK cells may play a significant role in the fight against Mtb. NK cells express various surface markers to recognize and kill both Mtb and Mtb-infected cells. In this review, recent advances in our understanding of NK cells in the fight against Mtb early during infection, with emphasis on cohort studies, will be presented.

Peroxiredoxins (PRXs) are intracellular antioxidative enzymes but work as inflammatory amplifiers under the extracellular condition. To date, the function of PRXs in the pathogenesis of multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) is not fully understood. The aim of this study was to investigate whether PRXs play a role in the pathogenesis of MS and NMOSD. We analyzed levels of PRXs (PRX1, PRX5, and PRX6) in the CSF and serum of 16 patients with MS, 16 patients with NMOSD, and 15 patients with other neurological disorders (ONDs). We identified potential correlations between significantly elevated PRXs levels and the clinical variables in patients with MS and NMOSD. Additionally, pathological analyses of PRXs (PRX1-6) in the central nervous system were performed using the experimental autoimmune encephalomyelitis (EAE), animal model of MS. We found that serum levels of PRX5 and PRX6 in patients with MS and NMOSD were higher compared with those in patients with ONDs (p < 0.05). Furthermore, high levels of PRX5 and PRX6 were partly associated with blood–brain barrier dysfunction and disease duration in NMOSD patients. No significant elevation was found in CSF PRXs levels of MS and NMOSD. Spinal cords from EAE mice showed remarkable PRX5 staining, especially in CD45+ infiltrating cells. In conclusion, PRX5 and PRX6 may play a role in the pathogeneses of MS and NMOSD.

Properdin is the only one positive regulator of the complement system. In this study, we characterize the prevalence, functional consequences and disease associations of autoantibodies against properdin in a cohort of patients with autoimmune disease systemic lupus erythematosus (SLE), suffering from lupus nephritis (LN). We detected autoantibodies against properdin in plasma of 22.5% of the LN patients (16/71) by ELISA. The binding of these autoantibodies to properdin was dose-dependent and was validated by surface plasmon resonance. Higher levels of anti-properdin were related to high levels of anti-dsDNA and ANA and to low concentrations of C3 and C4 in patients and also with histological signs of LN activity and chronicity. The high negative predictive value (NPV) of anti-properdin and anti-dsDNA combination suggested that patients who are both negative for anti-properdin and anti-dsDNA will not have severe nephritis. IgG from anti- properdin positive patients’ plasma increased the C3b deposition on late apoptotic cells by flow cytometry. Nevertheless, these IgGs did not modify substantially the binding of properdin to C3b, the C3 convertase C3bBb and the pro-convertase C3bB, evaluated by surface plasmon resonance. In conclusion, anti- properdin autoantibodies exist in LN patients. They have weak but relevant functional consequences, which could have pathological significance.

Tissue damage associated with trauma might release a sufficient autoantigen substrate to break immune tolerance. In a previous study, we showed that the leukopenia observed following severe inflammation is related to adenosine A1-receptor (A1R) desensitization and A2AR upregulation. We hypothesized that, under destructive pathological conditions this mechanism is beneficial in reducing prevalence of autoimmunity. In this study, we aim to evaluate the protective role of A1R and A2AR in prevention of autoimmune diseases. We used two murine models of autoimmune diseases: type 1 diabetes (T1D) induced by low-dose streptozotocin and pristane-induced lupus (PIL) and on neutrophils we studied NETosis regulation by adenosine. In both the T1D and PIL models, A1R-KO mice were predisposed to the development of autoimmunity. In the PIL model, in WT mice, parallel to the decline of A1R mRNA levels, lymphocytes number dropped (-85%) 6h after pristane injection. WT mice remained without any sign of disease at 36 weeks. In contrast, following pristane 43% of A1R-KO mice suffered from lupus-like disease. Compared to A1R-KO, in WT mice at 10 days A2AR mRNA levels were significantly higher. Similar to PIL, in T1D model the presence of A1R and A2AR was protective. In addition, we found that A1R increases and A2AR suppresses NETosis. We suggest that adenosine-dependent immune suppression and reduction in neutrophil extracellular traps (NETs) limits the reactive T-cells and development of anti-double strand DNA (dsDNA) antibodies that promote autoimmunity.