Clinical Immunology

Impairment of agonist-induced M2 muscarinic receptor activation by autoantibodies from chagasic patients with cardiovascular dysautonomia Publication date: March 2020 Source: Clinical Immunology, Volume 212 Author(s): Sabrina P. Beltrame, Laura C. Carrera Páez, Sergio R. Auger, Ahmad H. Sabra, Claudio R. Bilder, Claudia I. Waldner, Juan C. Goin Abstract Previous studies showed that circulating autoantibodies against M2 muscarinic receptors (anti-M2R Ab) are associated with decreased cardiac parasympathetic modulation in patients with chronic Chagas disease (CD). Here we investigated whether the exposure of M2R to such antibodies could impair agonist-induced receptor activation, leading to the inhibition of associated signaling pathways. Preincubation of M2R-expressing HEK 293T cells with serum IgG fractions from chagasic patients with cardiovascular dysautonomia, followed by the addition of carbachol, resulted in the attenuation of agonist-induced Gi protein activation and arrestin-2 recruitment. These effects were not mimicked by the corresponding Fab fractions, suggesting that they occur through receptor crosslinking. IgG autoantibodies did not enhance M2R/arrestin interaction or promote M2R internalization, suggesting that their inhibitory effects are not likely a result of short-term receptor regulation. Rather, these immunoglobulins could function as negative allosteric modulators of acetylcholine-mediated responses, thereby contributing to the development of parasympathetic dysfunction in patients with CD. Graphical abstract

Baseline derived neutrophil-to-lymphocyte ratio as a prognostic biomarker for non-colorectal gastrointestinal cancer patients treated with immune checkpoint blockade Publication date: March 2020 Source: Clinical Immunology, Volume 212 Author(s): Shuang Li, Jianling Zou, Chang Liu, Xi Jiao, Jifang Gong, Jian Li, Zhenghang Wang, Ming Lu, Zhihao Lu, Lin Shen Abstract Background Biomarkers in non-colorectal gastrointestinal (GI) cancer patients receiving immune checkpoint blockades (ICBs) are still limited. Methods Data were prospectively collected from a discovery cohort (n = 53) and a validation cohort (n = 107) in patients with non-colorectal GI cancer receiving ICB, as well as a chemotherapy-only cohort (n = 171). System inflammatory markers and derived neutrophil-to-lymphocyte ratio (dNLR) were determined as biomarkers by univariate and multivariate analyses. Results A higher level of dNLR (cutoff = 3) was associated with shorter overall survival (OS) in discovery and validation cohorts. In pooled cohort, disease control rate (DCR) (28% vs. 48.1%) was associated with dNLR (p = .017). In univariate analysis, original tumor site, tumor histopathology, number of metastases, and dNLR were correlated with OS. In multivariate analysis, higher dNLR level was correlated with reduced OS (10.43 months vs. 4.20 months, p < .001). In chemotherapy-only cohort, dNLR was also correlated with DCR and OS. Conclusion Higher dNLR level was correlated with worse outcomes, suggesting that dNLR may help risk-group stratification and assist disease management strategies as a prognostic biomarker for non-colorectal GI patients receiving ICB.

MicroRNA-9 ameliorates destructive arthritis through down-regulation of NF-κB1-RANKL pathway in fibroblast-like synoviocytes Publication date: March 2020 Source: Clinical Immunology, Volume 212 Author(s): Wen Shi Lee, Shinsuke Yasuda, Michihiro Kono, Yuki Kudo, Sanae Shimamura, Michihito Kono, Yuichiro Fujieda, Masaru Kato, Kenji Oku, Tomohiro Shimizu, Tomohiro Onodera, Norimasa Iwasaki, Tatsuya Atsumi Abstract We investigated the effect of miR-9 on fibroblast-like synoviocytes (FLS) from RA patients and animal arthritis model. The binding of miR-9 to NF-κB1 3’UTR was analyzed by luciferase reporter assay and immunoprecipitation. ChIP assay and luciferase promoter assay were performed to identify the binding of NF-κB1 to RANKL promoter and its activity. FLS were treated with miR-9/anti-miR-9 to evaluate cell proliferation and the expression of RANKL. Therapeutic effect of intra-articular miR-9 was evaluated in type-II collagen-induced arthritis in rats. miR-9 bound to the 3’-UTR of NF-κB1 and downregulated NF-κB1. NF-κB1 bound to RANKL promoter and increased the promoter activity of RANKL. RANKL was downregulated by miR-9. Proliferation of FLS was increased by miR-9 inhibitor. miR-9 dampened experimental arthritis by lowering inflammatory state, reducing RANKL and osteoclasts formation. Our findings revealed miR-9-NF-κB1-RANKL pathway in RA-FLS, further, miR-9 ameliorated inflammatory arthritis in vivo which propose therapeutic implications of miR- 9 in RA. Graphical abstract Known: miR-9 has lower expression in arthritis cartilage tissue. Normally, miR-9 binds to NF-κB1 or protegenin and promotes the survival and proliferation rate of chondrocyte as well as inhibits apoptosis. Loss of miR-9 will against this progress and hence reduce the cell numbers of chondrocytes [14,33]. However, miR-9 could also bind to MCPIP and upregulate the IL-6 expression which is the main cytokines in the progression of arthritis [35]. Bone fracture in vivo study has lower miR-9 expression which can promote the osteoclast precursor migration and increase the survival of osteoclast [34]. TNF-α induces IL-6 expression and the combination of IL-6/sIL-6R directly increases the expression of RANKL in RA-FLS [28]. Novel: In our study, we discover the role of NF-κB1 as one of the transcription factors to RANKL promoter, i.e. TNF-α and IFN-γ synergistically activates NF-κB signaling and hence upregulates RANKL expression in mRNA levels and protein levels (purple arrows). MiR-9 binds to NF-κB1 3’UTR and suppresses translational effect or cleaves NF-κB1 mRNA therefore suppresses the downstream of NF-κB1 signaling (red arrows). NF-κB1/p105 is processed by proteasome and produces NF-κB1/p50 which then enters the nucleus and acts as a transcription factor. RANKL expression and inflammation of RA are then indirectly downregulated by miR-9. Inhibiting miR-9 increases the proliferation of RA-FLS, which contributes to the pathophysiology of RA (green arrow) IL-6: interleukin-6; MCPIP: monocyte chemoattractant protein-induced protein 1; NF-κB1: nuclear factor kappa B; RA-FLS: rheumatoid arthritis fibroblast-like synoviocytes; RANKL: receptor activator nuclear factor kappa b ligand.

B cells in rheumatoid arthritis synovial tissues encode focused antibody repertoires that include antibodies that stimulate macrophage TNF-α production Publication date: Available online 5 February 2020 Source: Clinical Immunology Author(s): Serra E. Elliott, Sarah Kongpachith, Nithya Lingampalli, Julia Z. Adamska, Bryan J. Cannon, Lisa K. Blum, Michelle S. Bloom, Matthew Henkel, Mandy J. McGeachy, Larry W. Moreland, William H. Robinson Abstract Rheumatoid arthritis (RA) is characterized by the production of anti-citrullinated protein antibodies (ACPAs). To gain insights into the relationship between ACPA-expressing B cells in peripheral blood (PB) and synovial tissue (ST), we sequenced the B cell repertoire in paired PB and ST samples from five individuals with established, ACPA+ RA. Bioinformatics analysis of paired heavy and light chain sequences revealed clonally-related family members shared between PB and ST. ST-derived antibody repertoires exhibited reduced diversity and increased normalized clonal family size compared to PB-derived repertoires. Functional characterization showed that seven recombinant antibodies (rAbs) expressed from subject-derived sequences from both compartments bound citrullinated antigens and immune complexes (ICs) formed using one ST-derived rAb stimulated macrophage TNF-α production. Our findings demonstrate B cell trafficking between PB and ST in subjects with RA and ST repertoires include B cells that encode ACPA capable of forming ICs that stimulate cellular responses implicated in RA pathogenesis.

Cost and impact of early diagnosis in primary immunodeficiency disease: A literature review Publication date: Available online 5 February 2020 Source: Clinical Immunology Author(s): Kim Elsink, Joris M. van Montfrans, Mariëlle E. van Gijn, Maartje Blom, P. Martin van Hagen, T.W. Kuijpers, Geert W.J. Frederix Abstract Background New, innovative, costly diagnostic methods for patients with primary immunodeficiencies (PID) demand upfront insight into their potential cost savings and added value for individual patients. As such, high quality, comparable economic evaluations are of utmost importance to enable informed decisions. The objective of this review was therefore to create an extensive overview of current costing studies and potential cost savings of early diagnosis in primary immunodeficiency disease. Methods A literature search in PubMed was conducted and studies involving any form of costing study in the field of PIDs were included. Of the included studies, study characteristics, cost parameters and benefits of early diagnosis were extracted and outlined in separate tables. Results Twenty two studies met the inclusion criteria and were included in the review. The papers were categorized according to their subject: neonatal screening for severe combined immunodeficiency (SCID), Ig replacement therapies and studies reporting on costs of general or specific PIDs. Within and between these groups variability in reported costing characteristics was observed. In studies that reported cost savings pre- and post-diagnosis, cost savings ranged from 6500 to 108,463 USD of total costs per patient. Conclusion This literature review shows that, regardless of what aspect of PIDs has been studied, in nearly all cases early diagnosis reduces health care consumption and leads to better health outcomes for patients with PIDs. We found considerable variability in costing characteristics of economic evaluations of PID patients, which hampers the comparability of outcomes. More effort is needed to create uniformity and define cost parameters in economic evaluations in the field of PIDs, facilitating further prospective research to extensively assess the benefits of early diagnosis.

Mercury-induced autoimmunity: Drifting from micro to macro concerns on autoimmune disorders Publication date: Available online 4 February 2020 Source: Clinical Immunology Author(s): Geir Bjørklund, Massimiliano Peana, Maryam Dadar, Salvatore Chirumbolo, Jan Aaseth, Natália Martins Abstract Mercury (Hg) is widely recognized as a neurotoxic metal, besides it can also act as a proinflammatory agent and immunostimulant, depending on individual exposure and susceptibility. Mercury exposure may arise from internal body pathways, such as via dental amalgams, preservatives in drugs and vaccines, and seafood consumption, or even from external pathways, i.e., occupation, environmental pollution, and handling of metallic items and cosmetics containing Hg. In susceptible individuals, chronic low Hg exposure may trigger local and systemic inflammation, even exacerbating the already existing autoimmune response in patients with autoimmunity. Mercury exposure can trigger dysfunction of the autoimmune responses and aggravate immunotoxic effects associated with elevated serum autoantibodies titers. The purpose of the present report is to provide a critical overview of the many issues associated with Hg exposure and autoimmunity. In addition, the paper also focuses on individual susceptibility and other health effects of Hg.

Interactions of viruses and the humoral innate immune response Publication date: Available online 4 February 2020 Source: Clinical Immunology Author(s): Bailey E. Maloney, Krishani Dinali Perera, Danielle R.D. Saunders, Naemi Shadipeni, Sherry D. Fleming Abstract The innate immune response is crucial for defense against virus infections where the complement system, coagulation cascade and natural antibodies play key roles. These immune components are interconnected in an intricate network and are tightly regulated to maintain homeostasis and avoid uncontrolled immune responses. Many viruses in turn have evolved to modulate these interactions through various strategies to evade innate immune activation. This review summarizes the current understanding on viral strategies to inhibit the activation of complement and coagulation cascades, evade natural antibody-mediated clearance and utilize complement regulatory mechanisms to their advantage.

Longitudinal relationships between rheumatoid factor and cytokine expression by immunostimulated peripheral blood lymphocytes from patients with rheumatoid arthritis: New insights into B-cell activation Publication date: February 2020 Source: Clinical Immunology, Volume 211 Author(s): John M. Davis, Cynthia S. Crowson, Keith L. Knutson, Sara J. Achenbach, Michael A. Strausbauch, Terry M. Therneau, Eric L. Matteson, Sherine E. Gabriel, Peter J. Wettstein Abstract To identify associations between immunostimulated cytokine production and disease characteristics, peripheral blood lymphocytes were collected from 155 adult patients with rheumatoid arthritis (RA) before and after a 5-year interval. The lymphocytes were activated in vitro with T-cell stimulants, cytosine-phosphate-guanine (CpG) oligonucleotide, and medium alone (negative control). Expression of 17 cytokines was evaluated with immunoassays, and factor analysis was used to reduce data complexity and identify cytokine combinations indicative of cell types preferentially activated by each immunostimulant. The findings showed that the highest numbers of correlations were between cytokine levels and rheumatoid factor (RF) positivity and between cytokine levels and disease duration. Scores for cytokines driven by CpG and medium alone were negatively associated with RF positivity and disease duration at baseline but positively associated with both at 5 years. Our findings suggest that RF expression sustained over time increases activation of B cells and monocytes without requirements for T-cell functions.

The increased IL-17-producing γδT cells promote tumor cell proliferation and migration in neuroblastoma Publication date: February 2020 Source: Clinical Immunology, Volume 211 Author(s): Hui Zhang, Wenjia Chai, Wei Yang, Wei Han, Wenjun Mou, Yue Xi, Xi Chen, Hui Wang, Wei Wang, Hong Qin, Huanmin Wang, Xiaoli Ma, Xiaolin Wang, Jingang Gui Abstract Neuroblastoma (NB) is the most common solid extracranial malignancy in children with a considerable chance of metastatic progression. Prevalent evidence supports the anti-tumor role of γδT cells and these cells have been testing in clinical trials for constraining tumor growth. A small subpopulation of γδT cells releasing IL-17, however, were demonstrated to exert tumor-promoting effects in many aspects. In this study, we found an augment of IL-17+ γδT cells both in in vitro PAM-stimulated γδT-cell expanding culture and circulating γδT cells in NB patients. These patient-origin cells expanded in vitro by PAM in the presence of IL-17 polarizing condition were shown to promote the proliferation and migration of NB cells. Furthermore, an intrinsic preference for IL-17 polarization in NB γδT cells was revealed by mRNA microarray and Western Blot, which pointed to an up-regulated expression of multiple Th17-development related genes in addition to an increased phosphorylation level of STAT3.

Predictive value of mesangial C3 and C4d deposition in IgA nephropathy Publication date: February 2020 Source: Clinical Immunology, Volume 211 Author(s): Ki Heon Nam, Young Su Joo, Changhyun Lee, Sangmi Lee, Joohwan Kim, Hae-Ryong Yun, Jung Tak Park, Tae Ik Chang, Dong-Ryeol Ryu, Tae-Hyun Yoo, Ho Jun Chin, Shin-Wook Kang, Hyeon Joo Jeong, Beom Jin Lim, Seung Hyeok Han, on behalf of The Korean GlomeruloNEphritis sTudy (KoGNET) Group Abstract We aimed to determine the relative contribution of each complement (C3 and C4d) deposition to the progression of IgA nephropathy (IgAN). We enrolled a total of 380 patients with biopsy-confirmed IgAN. Mesangial deposition of C3(<2+ vs. ≥2+) and C4d(positive vs. negative) was evaluated by immunofluorescence staining and immunohistochemistry, respectively. Study endpoint was the composite of a 30% decline in eGFR or ESRD. The risk of reaching the primary outcome was significantly higher in patients having C3 ≥ 2+ and C4d(+) than in corresponding counterparts. Adding C3 deposition to clinical data acquired at kidney biopsy modestly increased the area under the receiver-operating characteristic curve, net reclassification improvement, and integrated discrimination improvement (IDI); adding C4d increased IDI only. In conclusion, mesangial C3 and C4d deposition was an independent risk factor for progression of IgAN. C3 showed better predictability than C4d, suggesting that lectin pathway alone has limited clinical prognostic value.