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Purpose: Secondary myeloid neoplasms (sMNs) remain the most serious long-term complications in patients with aplastic anemia (AA) and paroxysmal nocturnal hemoglobinuria (PNH). However, sMNs lack specific predictors, dedicated surveillance measures, and early therapeutic interventions., Patients and Methods: We studied a multicenter, retrospective cohort of 1,008 patients (median follow-up 8.6 years) with AA and PNH to assess clinical and molecular determinants of clonal evolution., Results: Although none of the patients transplanted upfront (n = 117) developed clonal complications (either sMN or secondary PNH), the 10-year cumulative incidence of sMN in nontransplanted cases was 11.6%. In severe AA, older age at presentation and lack of response to immunosuppressive therapy were independently associated with increased risk of sMN, whereas untreated patients had the highest risk among nonsevere cases. The elapsed time from AA to sMN was 4.5 years. sMN developed in 94 patients. The 5-year overall survival reached 40% and was independently associated with bone marrow blasts at sMN onset. Myelodysplastic syndrome with high-risk phenotypes, del7/7q, and ASXL1 , SETBP1 , RUNX1 , and RAS pathway gene mutations were the most frequent characteristics. Cross-sectional studies of clonal dynamics from baseline to evolution revealed that PIGA/ human leukocyte antigen lesions decreased over time, being replaced by clones with myeloid hits. PIGA and BCOR/L1 mutation carriers had a lower risk of sMN progression, whereas myeloid driver lesions marked the group with a higher risk., Conclusion: The risk of sMN in AA is associated with disease severity, lack of response to treatment, and patients' age. sMNs display high-risk morphological, karyotypic, and molecular features. The landscape of acquired somatic mutations is complex and incompletely understood and should be considered with caution in medical management.

Background: HLAs contain combinations of multiple eplets, sometimes shared between numerous HLA alleles. Some authors suggested that single antigen bead (SAB) assays may underestimate the signal of anti-HLA antibodies (Ab) when several beads share the targeted eplet. However, this assumption has not yet been validated experimentally., Methods: We selected 5 eplets shared by 1-24 beads of the routine SAB kits: the eplet 163LS/G; the 3 eplets 127K, 62GE, and 62GRN thereafter called cross-reactive group 2C; the 82LR eplet, well-known as Bw4; the locally called QB2A5 eplet associated with the DQA1*05:01/DQB1*02:01 combination; and the 40GR DQ eplet. We selected a dozen of sera for each eplet with Ab mean fluorescence intensity (MFI) between 1000 and 15 000 for the beads carrying the targeted eplet. We tested them with the classical SAB panel (SABp), with an isolated bead carrying the eplet (isolated SAB [SABi]) and with a mixture of both (SABp+i)., Results: No significant difference in MFI was detected among SABi, SABp, and SABp+i conditions for all the eplets., Conclusions: We noticed only a nonsignificant difference in the Ab MFI signal due to eplet sharing on the SAB assay. We, therefore, conclude that this phenomenon should no longer be considered as a significant risk factor during patient follow-up pre- or posttransplantation., Competing Interests: The authors declare no funding or conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the most effective treatment for selected patients with acute myeloid leukemia (AML) and relies on a "graft-versus-leukemia" effect (GVL) where donor T lymphocytes mediate control of malignant cell growth. However, relapse remains the major cause of death after allo-HSCT. In various malignancies, several immunoregulatory mechanisms have been shown to restrain antitumor immunity, including ligand-mediated engagement of inhibitory receptors (IRs) on effector cells, and induction of immunosuppressive cell subsets, such as regulatory T cells (Tregs) or myeloid-derived suppressor cells (MDSCs). Relapse after HSCT remains a major therapeutic challenge, but immunoregulatory mechanisms involved in restraining the GVL effect must be better deciphered in humans. We used mass cytometry to comprehensively characterize circulating leukocytes in 2 cohorts of patients after allo-HSCT. We first longitudinally assessed various immunoregulatory parameters highlighting specific trends, such as opposite dynamics between MDSCs and Tregs. More generally, the immune landscape was stable from months 3 to 6, whereas many variations occurred from months 6 to 12 after HSCT. Comparison with healthy individuals revealed that profound alterations in the immune equilibrium persisted 1 year after HSCT. Importantly, we found that high levels of TIGIT and CD161 expression on CD4 T cells at month 3 after HSCT were distinct features significantly associated with subsequent AML relapse in a second cross-sectional cohort. Altogether, these data provide global insights into the reconstitution of the immunoregulatory landscape after HSCT and highlight non-canonical IRs associated with relapse, which could open the path to new prognostic tools or therapeutic targets to restore subverted anti-AML immunity., (© 2022 by The American Society of Hematology.)

Previous studies reporting the response to SARS-CoV-2 mRNA vaccination in alloHSCT recipients used serological and/or cellular assays, but no study has evaluated vaccine-induced neutralizing antibodies. We prospectively studied 28 alloHSCT recipients who received two BNT162b2 doses. Two patients groups were defined according to time from alloHSCT and immunosuppressive treatment, and had different baseline immunologic status. Study end-point was the evaluation of humoral and cellular responses one month after the second vaccine. All patients seroconverted. Anti-S IgG levels and neutralizing antibodies percentages were not significantly different between both groups. Using IFNγ ELISpot assay, five patients showed a strong increase, without correlation with the humoral response. Using flow cytometry lymphocyte proliferation assay, 14 patients exhibited responding T cells, without difference between both groups or correlation with anti-S IgG levels. A few low serological responders had a detectable CD4 + T cell proliferative response. This finding should be confirmed in a larger cohort., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

HLA-DQA1*01:81 differs from HLA-DQA1*01:02:01:01 by one nucleotide substitution in codon 153 in exon 3., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Aims/hypothesis: Insulin allergy is a rare but significant clinical challenge. We aimed to develop a management workflow by (1) validating clinical criteria to guide diagnosis, based on a retrospective cohort, and (2) assessing the diagnostic performance of confirmatory tests, based on a case-control study., Methods: In the retrospective cohort, patients with suspected insulin allergy were classified into three likelihood categories according to the presence of all (likely insulin allergy; 26/52, 50%), some (possible insulin allergy; 9/52, 17%) or none (unlikely insulin allergy; 17/52, 33%) of four clinical criteria: (1) recurrent local or systemic immediate or delayed hypersensitivity reactions; (2) reactions elicited by each injection; (3) reactions centred on the injection sites; and (4) reactions observed by the investigator (i.e. in response to an insulin challenge test). All underwent intradermal reaction (IDR) tests. A subsequent case-control study assessed the diagnostic performance of IDR, skin prick and serum anti-insulin IgE tests in ten clinically diagnosed insulin allergy patients, 24 insulin-treated non-allergic patients and 21 insulin-naive patients., Results: In the retrospective cohort, an IDR test validated the clinical diagnosis in 24/26 (92%), 3/9 (33%) and 0/14 (0%) likely, possible and unlikely insulin allergy patients, respectively. In the case-control study, an IDR test was 80% sensitive and 100% specific and identified the index insulin(s). The skin prick and IgE tests had a marginal diagnostic value. Patients with IDR-confirmed insulin allergy were treated using a stepwise strategy., Conclusions/interpretation: Subject to validation, clinical likelihood criteria can effectively guide diabetologists towards an insulin allergy diagnosis before undertaking allergology tests. An IDR test shows the best diagnostic performance. A progressive management strategy can subsequently be implemented. Continuous subcutaneous insulin infusion is ultimately required in most patients., Clinicaltrials: gov: NCT01407640., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Complement-mediated interference is a well described phenomenon in single antigen bead (SAB) Luminex assay that leads to falsely low or negative results for anti-HLA antibody (Ab). In a context of high amount of Ab, the enrichment of the Ab around the bead can lead to complement cascade activation and deposition, thereafter impairing Ab detection. EDTA is now routinely used to circumvent this interference. In this report, we attempted to decipher the role of the phycoerythrin (PE) label conjugated to the secondary Ab in this interference. Indeed, PE is a huge molecule (240 kDa) that could participate to limiting access of the conjugate to its Ab target on the bead. To this purpose, 22 sera displaying complement interference without pre-treatment with EDTA were compared on SAB assay with three detection strategies: the recommended PE-conjugated secondary Ab (IgGPE), an Alexa Fluor 532-conjugated Ab (IgGAF) bearing a tiny 724 Da fluorochrome, and a biotinylated Ab followed by PE-conjugated streptavidin (IgGBiot). Complement interference occurred with the three detection methods, but its depth, defined by the percentage of MFI loss with neat serum, was the highest for IgGPE. Our study highlighted the partial role of the PE fluorochrome in complement interference in SAB assays., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Although the treatment of iatrogenic and HIV-related Kaposi sarcoma is well defined and mostly based on restoring immune function, the treatment of classic and endemic Kaposi sarcoma is less well established. Chemotherapy or interferon α is used for patients with extensive cutaneous or visceral Kaposi sarcoma, but tolerance might be poor and long-term remission is rare. We aimed to evaluate the activity of pembrolizumab in classic and endemic Kaposi sarcoma with cutaneous extension requiring systemic treatment., Methods: We did a multicentre, single-arm, proof-of-concept, phase 2 trial in adults aged 18 years or older with histologically proven classic or endemic Kaposi's sarcoma with progressive cutaneous extension requiring systemic treatment and an Eastern Cooperative Oncology Group performance status of 0-1 in three hospitals in France. The patients were treated with 200 mg pembrolizumab intravenously every 3 weeks for 6 months (eight cycles) or until severe toxicity. The primary endpoint was the best overall response rate within the 6-month timeframe, defined by the occurrence of a complete response or partial response and assessed by an investigator using the modified AIDS Clinical Trial Group (ACTG) criteria. Three or more responses among a total 17 patients were needed for the primary endpoint to be met, using a Simon's two-stage optimal design assuming a 30% response rate as desirable. For this final study analysis, all patients were included following the intention-to-treat principle. This study is registered with ClinicalTrials.gov, NCT03469804, and is closed to new participants., Findings: 30 patients were screened for eligibility and 17 patients (eight [47%] with classic and nine [53%] with endemic Kaposi's sarcoma) were enrolled between July 2, 2018, and Dec 16, 2019. The median follow-up was 20·4 months (IQR 18·1-24·1). Two (12%) patients had a complete response, ten (59%) had a partial response, and five (29%) had stable disease as the best response within the 6-month treatment timeframe, with a best overall response rate of 71% (95% CI 44-90), meeting the predefined primary outcome (ie, exceeding a response rate of 30%). Treatment-related adverse events occurred in 13 (76%) of 17 patients, including two grade 3 adverse events (one [6%] acute cardiac decompensation and one [6%] granulomatous reaction). Treatment was prematurely discontinued in two (12%) patients due to grade 3 acute reversible cardiac decompensation and grade 2 pancreatitis, and one other patient had a grade 3 granulomatous reaction in mediastinal lymph nodes requiring steroids and methotrexate treatment. There were no serious adverse events or treatment-related deaths., Interpretation: In this prospective trial, which to our knowledge is the first to assess the role of PD-1 blockade in patients with classic and endemic Kaposi's sarcoma, pembrolizumab showed promising anti-tumour activity with an acceptable safety profile. If this result is supported by further studies, treatment with anti-PD-1 could be part of the therapeutic armamentarium for patients with classic and endemic Kaposi's sarcoma., Funding: MSD France., Competing Interests: Declarations of interests JD reports support for travel or accommodation from Pierre Fabre and Roche; research funding from Merck Sharpe and Dohme and Amgen; and honoraria from Bristol Myers Squibb. SD reports institutional research grants from and travel costs covered by Bristol Myers Squibb and Merck Sharpe and Dohme. VH reports support for attending meetings from Merck Sharpe and Dohme. SM reports a consulting role for and research funding from Novartis, Bristol Myers Squibb, Biocartis, and Roche. VA reports support for attending meetings from Bediagenomics. MB reports board member fees from Bristol Myers Squibb; travel expenses from Roche; research grants from Takeda; expert consultancy for Innate Pharma and Kyowa Kirin; and speaker board fees from Kyowa Kirin. CL reports research funding from Roche and Bristol Myers Squibb; consulting fees from Bristol Myers Squibb, Merck Sharpe and Dohme, Novartis, Amgen, Roche, Merck Serono, Sanofi, and Pierre Fabre; honoraria from Roche, Bristol Myers Squibb, Novartis, Amgen, Merck Sharpe and Dohme, Pierre Fabre, Pfizer, and Incyte; fees for speaker's bureau from Roche, Bristol Myers Squibb, Novartis, Amgen, and Merck Sharpe and Dohme; support for attending meetings from Bristol Myers Squibb, Merck Sharpe and Dohme, Novartis, Sanofi, and Pierre Fabre; and fees from Avantis Medical Systems. All other authors declare no competing interests., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Vaccination against coronavirus disease 2019 (COVID-19) relies on the in-depth understanding of protective immune responses to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). We characterized the polarity and specificity of memory T cells directed against SARS-CoV-2 viral lysates and peptides to determine correlates with spontaneous, virus-elicited, or vaccine-induced protection against COVID-19 in disease-free and cancer-bearing individuals. A disbalance between type 1 and 2 cytokine release was associated with high susceptibility to COVID-19. Individuals susceptible to infection exhibited a specific deficit in the T helper 1/T cytotoxic 1 (Th1/Tc1) peptide repertoire affecting the receptor binding domain of the spike protein (S1-RBD), a hotspot of viral mutations. Current vaccines triggered Th1/Tc1 responses in only a fraction of all subject categories, more effectively against the original sequence of S1-RBD than that from viral variants. We speculate that the next generation of vaccines should elicit Th1/Tc1 T-cell responses against the S1-RBD domain of emerging viral variants., Significance: This study prospectively analyzed virus-specific T-cell correlates of protection against COVID-19 in healthy and cancer-bearing individuals. A disbalance between Th1/Th2 recall responses conferred susceptibility to COVID-19 in both populations, coinciding with selective defects in Th1 recognition of the receptor binding domain of spike. See related commentary by McGary and Vardhana, p. 892. This article is highlighted in the In This Issue feature, p. 873., (©2022 The Authors; Published by the American Association for Cancer Research.)

Chimeric Antigen Receptor T cells (CAR-T) are an outbreaking treatment option for relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL). Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) are the most common specific toxicities, while severe neutropenia and infections are often observed as well. From March 2020, early G-CSF prophylaxis at day (D) two post-infusion was systematically proposed. We then compared patients treated before that date who did not receive G-CSF or who received late (after D5) G-CSF as control group. Patients administered with early G-CSF had similar duration of grade 4 neutropenia but significantly decreased incidence of febrile neutropenia (58% versus 81%, p = 0.018). Similar rate of toxicities was observed, including overall and grade 3-4 CRS (p = 0.93 and p = 0.28, respectively), and overall and grade 3-4 ICANS (p = 0.62 and p = 0.88, respectively). We observed no difference in the quality of CAR T-cells expansion (p = 0.79, %Cmax), nor in response rate (best ORR, 57.6% vs 61.8%, p = 0.93), nor survival even in a group of patients adjusted by a propensity score. In conclusion, early G-CSF administration was safe and effective in reducing febrile neutropenia without impact on toxicities nor on anti-lymphoma activity of CAR-T., (© 2021. The Author(s).)

Tisagenlecleucel therapy has shown promising efficacy for relapsed/refractory (R/R) B-cell precursor acute lymphoblastic leukemia (BCP-ALL). However, relapses occur in 30-50% of patients. Determinants for CD19 pos versus CD19 neg relapses are poorly characterized. We report on 51 patients with R/R BCP-ALL (median age 17 years) infused with tisagenlecleucel after lymphodepletion. Complete remission rate at D28 was 96%. Prior blinatumomab increased the risk of early failure at D28. The 18-month cumulative incidence of relapse (CIR), event-free survival (EFS), and overall survival (OS) were 51%, 44%, and 74%, respectively, at a median follow-up of 15.5 months. Factors associated with a high tumor burden (occurrence of cytokine release syndrome) and prior blinatumomab were associated with an increased CIR, and a shorter EFS and OS. Pre-lymphodepletion high disease burden (MRD ≥ 10 -2 , SHR 10.4, p = 0.03) and detectable MRD at D28 (SHR 7.2, p = 0.006) correlated with an increased risk of CD19 neg relapse. Low disease burden (SHR 5.3, p = 0.03) and loss of B-cell aplasia (BCA) (SHR 21.7, p = 0.004) predicted an increased risk of CD19 pos relapses. These data highlight the impact of prior therapy on patient outcome. Finally, detectable MRD at D28 and loss of BCA both define patients at high risk of relapse for whom additional interventions are needed., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

CAR-T cells represent a new anti-tumor immunotherapy which has shown its clinical efficacy in B-cell malignancies. The results of clinical trials carried out in this context have shown that certain immunological characteristics of patients before (at the time of apheresis) and after the administration of the treatment, or of the CAR-T cells themselves, are correlated with the response to the treatment or to its toxicity. However, to date, there are no recommendations on the immunological monitoring of patients treated in real life. The objectives of this workshop were to determine, based on data from the literature and the experience of the centers, the immunological analyses to be carried out in patients treated with CAR-T cells. The recommendations relate to the characterization of the patient's immune cells at the time of apheresis, the characterization of the injected CAR-T cells, as well as the monitoring of the CAR-T cells and other parameters of immune reconstitution in the patient after administration of the treatment. Harmonization of practices will allow clinical-biological correlation studies to be carried out in patients treated in real life with the aim of identifying factors predictive of response and toxicity. Such data could have a major medico-economic impact by making it possible to identify the patients who will optimally benefit from these expensive treatments., (Copyright © 2021 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.)

Treatment of hematological malignancies by autologous T cells expressing a chimeric antigen receptor (CAR) is a breakthrough in the field of cancer immunotherapy. As CAR-T cells are entering advanced phases of clinical development, there is a need to develop universal, ready-to-use products using immune cells from healthy donors, to reduce time to treatment, improve response rate and finally reduce the cost of production. Mucosal-associated invariant T cells (MAIT) are unconventional T cells which recognize microbial-derived riboflavin derivatives presented by the conserved MR1 molecule and are endowed with potent effector functions. Because they are not selected by classical MHC/peptide complexes and express a semi-invariant T cell receptor, MAIT cells do not mediate alloreactivity, prompting their use as a new source of universal effector cells for allogeneic CAR-T cell therapy without the need to inactivate their endogenous TCR. We produced CD19-CAR MAIT cells as proof-of-concept allowing subsequent head-to-head comparison with currently used CD19-CAR T cells. We demonstrated their anti-tumor efficacy in vitro and their capacity to engraft without mediating GVHD in preclinical immunodeficient mouse models. Universal, off-the-shelf CAR-MAIT cells could provide a suitable alternative to current autologous CAR-T cells to treat patients regardless of HLA disparity, without production delay, enabling a cost-effective manufacturing model for large-scale clinical application., (Copyright © 2021 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.)

Background: The HLA evolutionary divergence (HED), a continuous metric quantifying the peptidic differences between 2 homologous HLA alleles, reflects the breadth of the immunopeptidome presented to T lymphocytes., Objective: To assess the potential effect of donor or recipient HED on liver transplant rejection., Design: Retrospective cohort study., Setting: Liver transplant units., Patients: 1154 adults and 113 children who had a liver transplant between 2004 and 2018., Measurements: Liver biopsies were done 1, 2, 5, and 10 years after the transplant and in case of liver dysfunction. Donor-specific anti-HLA antibodies (DSAs) were measured in children at the time of biopsy. The HED was calculated using the physicochemical Grantham distance for class I ( HLA-A or HLA-B ) and class II ( HLA-DRB1 or HLA-DQB1 ) alleles. The influence of HED on the incidence of liver lesions was analyzed through the inverse probability weighting approach based on covariate balancing, generalized propensity scores., Results: In adults, class I HED of the donor was associated with acute rejection (hazard ratio [HR], 1.09 [95% CI, 1.03 to 1.16]), chronic rejection (HR, 1.20 [CI, 1.10 to 1.31]), and ductopenia of 50% or more (HR, 1.33 [CI, 1.09 to 1.62]) but not with other histologic lesions. In children, class I HED of the donor was also associated with acute rejection (HR, 1.16 [CI, 1.03 to 1.30]) independent of the presence of DSAs. There was no effect of either donor class II HED or recipient class I or class II HED on the incidence of liver lesions in adults and children., Limitation: The DSAs were measured only in children., Conclusion: Class I HED of the donor predicts acute or chronic rejection of liver transplant. This novel and accessible prognostic marker could orientate donor selection and guide immunosuppression., Primary Funding Source: Institut National de la Santé et de la Recherche Médicale.

Background: Mucosal-associated invariant T (MAIT) cells are semi-invariant T cells that recognize microbial antigens presented by the highly conserved MR1 molecule. MAIT cells are predominantly localized in the liver and barrier tissues and are potent effectors of antimicrobial defense. MAIT cells are very few at birth and accumulate gradually over a period of about 6 years during the infancy. The cytotoxic potential of MAIT cells, as well as their newly described regulatory and tissue repair functions, open the possibility of exploiting their properties in adoptive therapy. A prerequisite for their use as 'universal' cells would be a lack of alloreactive potential, which remains to be demonstrated., Methods: We used ex vivo, in vitro and in vivo models to determine if human MAIT cells contribute to allogeneic responses., Results: We show that recovery of MAIT cells after allogeneic hematopoietic stem cell transplantation recapitulates their slow physiological expansion in early childhood, independent of recovery of non-MAIT T cells. In vitro, signals provided by allogeneic cells and cytokines do not induce sustained MAIT cell proliferation. In vivo, human MAIT cells do not expand nor accumulate in tissues in a model of T-cell-mediated xenogeneic graft-versus-host disease in immunodeficient mice., Conclusions: Altogether, these results provide evidence that MAIT cells are devoid of alloreactive potential and pave the way for harnessing their translational potential in universal adoptive therapy overcoming barriers of HLA disparity., Trial Registration Number: ClinicalTrials.gov number NCT02403089., Competing Interests: Competing interests: No, there are no competing interests., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Genetically engineered chimeric antigen receptor (CAR) T lymphocytes are promising therapeutic tools for cancer. Four CAR T cell drugs, including tisagenlecleucel (tisa-cel) and axicabtagene-ciloleucel (axi-cel), all targeting CD19, are currently approved for treating B cell malignancies. Flow cytometry (FC) remains the standard for monitoring CAR T cells using a recombinant biotinylated target protein. Nevertheless, there is a need for additional tools, and the challenge is to develop an easy, relevant, highly sensitive, reproducible, and inexpensive detection method. Molecular tools can meet this need to specifically monitor long-term persistent CAR T cells., Methods: Based on 2 experimental CAR T cell constructs, IL-1RAP and CS1, we designed 2 quantitative digital droplet (ddPCR) PCR assays. By targeting the 4.1BB/CD3z (28BBz) or 28/CD3z (28z) junction area, we demonstrated that PCR assays can be applied to approved CD19 CAR T drugs. Both 28z and 28BBz ddPCR assays allow determination of the average vector copy number (VCN) per cell. We confirmed that the VCN is dependent on the multiplicity of infection and verified that the VCN of our experimental or GMP-like IL-1RAP CAR T cells met the requirement (< 5 VCN/cell) for delivery to the clinical department, similar to approved axi-cel or tisa-cel drugs., Results: 28BBz and 28z ddPCR assays applied to 2 tumoral (acute myeloid leukemia (AML) or multiple myeloma (MM) xenograft humanized NSG mouse models allowed us to quantify the early expansion (up to day 30) of CAR T cells after injection. Interestingly, following initial expansion, when circulating CAR T cells were challenged with the tumor, we noted a second expansion phase. Investigation of the bone marrow, spleen and lung showed that CAR T cells disseminated more within these tissues in mice previously injected with leukemic cell lines. Finally, circulating CAR T cell ddPCR monitoring of R/R acute lymphoid leukemia or diffuse large B cell lymphoma (n = 10 for tisa-cel and n = 7 for axi-cel) patients treated with both approved CAR T cells allowed detection of early expansion, which was highly correlated with FC, as well as long-term persistence (up to 450 days), while FC failed to detect these events., Conclusion: Overall, we designed and validated 2 ddPCR assays allowing routine or preclinical monitoring of early- and long-term circulating approved or experimental CAR T cells, including our own IL-1RAP CAR T cells, which will be evaluated in an upcoming phase I clinical trial.

Background: Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection causes direct lung damage, overwhelming endothelial activation, and inflammatory reaction, leading to acute respiratory failure and multi-organ dysfunction. Ongoing clinical trials are evaluating targeted therapies to hinder this exaggerated inflammatory response. Critically ill coronavirus disease 2019 (COVID-19) patients have shown heterogeneous severity trajectories, suggesting that response to therapies is likely to vary across patients., Research Question: Are critically ill COVID-19 patients biologically and immunologically dissociable based on profiling of currently evaluated therapeutic targets?, Study Design and Methods: We did a single-center, prospective study in an ICU department in France. Ninety-six critically ill adult patients admitted with a documented SARS-CoV-2 infection were enrolled. We conducted principal components analysis and hierarchical clustering on a vast array of immunologic variables measured on the day of ICU admission., Results: We found that patients were distributed in three clusters bearing distinct immunologic features and associated with different ICU outcomes. Cluster 1 had a "humoral immunodeficiency" phenotype with predominant B-lymphocyte defect, relative hypogammaglobulinemia, and moderate inflammation. Cluster 2 had a "hyperinflammatory" phenotype, with high cytokine levels (IL-6, IL-1β, IL-8, tumor necrosis factor-alpha [TNF⍺]) associated with CD4+ and CD8+ T-lymphocyte defects. Cluster 3 had a "complement-dependent" phenotype with terminal complement activation markers (elevated C3 and sC5b-9)., Interpretation: Patients with severe COVID-19 exhibiting cytokine release marks, complement activation, or B-lymphocyte defects are distinct from each other. Such immunologic variability argues in favor of targeting different mediators in different groups of patients and could serve as a basis for patient identification and clinical trial eligibility., (Copyright © 2020 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Luminex single antigen flow beads (SAFB) assays are used to monitor anti-HLA antibodies, which are associated with allograft loss. The primary antibody binding level is evaluated by the mean fluorescence intensity (MFI) provided by the tracing secondary antibody. The aim of this study was to compare the MFI obtained with two secondary antibodies and to evaluate their sensitivity to detect newly developed de novo anti-HLA donor-specific antibodies (dnDSA). A total of 23 and 46 different sera from 20 HLA-sensitized kidney transplant recipients were tested with class I and II SAFB, respectively, as well as sera from 17 patients with dnDSA. The conventional secondary antibody (IgHPolyFab) was the phycoerythrin (PE)-conjugated goat anti-human IgG constant heavy chain (HC)-binding polyclonal-F(ab')2. The alternate secondary antibody was a PE-conjugated anti-human IgG Fc-specific monoclonal IgG (FcMonoIgG). MFI of negative control sera were drastically lower with the FcMonoIgG than with IgHPolyFab, requesting a unique positivity threshold to be defined for each secondary antibody. MFI obtained with positive control sera were also lower with FcMonoIgG. In kidney transplant recipient's sera, the number of antigenic specificities detected by each secondary antibody was comparable, for dnDSA as well as for nonDSA. In conclusion, decision thresholds must be refined when changing the secondary tracing reagent in SAFB assays. FcMonoIgG did not demonstrate any superiority over IgHPolyFab for monitoring HLA antibodies., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Pre-transplant serum screening of anti-HLA antibodies is recommended for solid organ transplantations. Many laboratories use the less expensive bead-based screening assay as the main technique and, if positive, turn to single-antigen beads (SAB). We studied the correlations between these two immunoassays. We re-analyzed the raw data of the two assays in 3030 first organ transplant recipients, explored with the two tests. We performed a ROC curve analysis of the screening ratio to predict a positive SAB assay. The AUC were 0.72 and 0.64 for class I and class II. The optimal thresholds of screening ratios were 3.28 (class I) and 2.11 (class II). Whatever the class, the negative predictive value was low, around 40%, with 36% of discordant sera, as defined by negative screening and positive SAB. Testing class I discordant sera on acid-treated SAB showed that 54% of antibodies reacted against denatured HLA molecules. However, these screening-negative sera may contain donor-specific antibodies in 13.9% and 28.7% of cases for class I and class II, respectively, involved in antibody-mediated rejection with the same frequency as non-discordant sera. Given the low predictive value of screening, both assays should be performed at least once on the same serum before transplantation., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Post-transplantation lymphoproliferative disease (PTLD) is a serious complication associated with Epstein-Barr virus (EBV) infection after hematopoietic stem cell transplantation (HSCT). Although anti-CD-20 therapy is now used as a preemptive strategy for EBV reactivation, PTLD still occurs in some patients. Here we analyzed outcomes and risk factors associated with PTLD transformation in 208 HSCT recipients who were diagnosed with EBV-DNAemia and received at least 1 course of rituximab. The median patient age was 42.52 years (range, 8.35 to 74.77 years), and the median duration of follow-up was 47.33 months (range, 3.18 to 126.20 months). The 2-year overall survival of the entire cohort was 62.8 (95% confidence interval [CI], 56.4 to 69.9), and the 2-year cumulative incidence function of PTLD was 6.3% (95% CI, 3.5% to 10.1%), for a median follow-up of patients diagnosed with PTLD of 37.85 months. Multivariable analysis identified 4 risk factors associated with PTLD: HSCT from an unrelated donor, recipient HLA-DRB1*11:01, fever at diagnosis of EBV infection, and donor-recipient sex-mismatched HSCT. The presence of more than 2 of these risk factors was associated with an increased risk of developing PTLD. This retrospective study identifies risk factors associated with PTLD in EBV-infected patients after HSCT and defines patient subgroups that may benefit from intensified preemptive strategies., (Copyright © 2019 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Mucosal associated invariant T (MAIT) cells are unconventional, semi-invariant T lymphocytes that recognize microbial-derived vitamin B2 (riboflavin) biosynthesis precursor derivatives presented by the monomorphic MHC class 1-related (MR1) molecule. Upon microbial infection, MAIT cells rapidly produce cytokines and cytotoxic effectors, and are thus important players in anti-microbial defense. MAIT cells are protective in experimental models of infection and are decreased in the blood of adult patients with bacterial infections, including Mycobacterium tuberculosis ( Mtb ). In children, the risk of rapid progression to active tuberculosis (TB) following Mtb infection is higher than in adults. Whether MAIT cells influence the outcome of Mtb infection in children is therefore, an important issue. We analyzed MAIT cell numbers and phenotype in 115 children investigated for pulmonary TB and determined their potential correlation with disease progression. MAIT cells were reduced in numbers and activated in the peripheral blood of children with active TB as compared to those with latent TB infection (LTBI) and healthy children. Moreover, MAIT cells did not accumulate and did not proliferate in the lung of children with active TB. These results suggest that MAIT cells may be important in preventing progression of Mtb infection to active TB in children.

Hematopoietic stem cell transplantation (HSCT) using unrelated cord blood (CB) donors is a suitable approach when an HLA-matched donor is not available. However, one important drawback is the risk of life-threatening viral infections prior to immune reconstitution, particularly from adenoviruses (AdVs). Although adoptive therapy with ex vivo expanded virus-reactive donor T cells has proven effective to treat these infections in HSCT recipients, the manufacturing process is complex and requires large numbers of cells, which is incompatible with CB donor units. Here, we have adapted our previous accelerated co-cultured dendritic cell (acDC) method, which allows to efficiently and rapidly expand peripheral blood T cells reactive to a given antigen, for use on limited CB material. Selected cytokine cocktails induced DC differentiation and maturation from unfractionated CB mononuclear cell cultures and simultaneously stimulated and expanded, within 10 days, functional CD8 + T cells specific for the model antigen MelanA or AdV immunodominant peptides. In addition, the use of G-Rex cultures yielded numbers of AdV-reactive CD8 + T cells compatible with adoptive cell therapy applications. Our acDC strategy, which uses reagents compatible with good manufacturing practices, may be promptly translated into the clinic for treating intercurrent infections in CB HSCT recipients.

Presence of anti-human leukocyte antigen donor-specific antibodies (DSAs) is associated with poor outcome after lung transplantation. Currently, DSAs are detected using the Luminex technique, which may be overly sensitive. The new C1q assay allows for the exclusive detection of complement (C1q)-binding antibodies, involved in antibody-mediated rejection. We investigated whether early detection of complement-binding DSAs is associated with chronic lung allograft dysfunction (CLAD) and survival.From 2009 to 2012, lung transplant recipients from three transplantation centres were screened for the presence of DSA and their complement-binding capacity during the 6-12 months post-transplantation in a stable condition.The analysis included 168 patients. The 3-year rates of freedom from CLAD and graft survival were lower for patients with complement-binding DSAs (33.6% and 53.7%, respectively), as compared with patients with non-complement-binding DSAs (61.9% and 77.4%, respectively) and patients without DSA (70% and 84.9%, respectively) (p<0.001 and p=0.001, respectively). Detection of complement-binding DSA was associated with a risk of graft loss that was nearly tripled after adjustment for clinical, functional, histological and immunological factors (hazard ratio 2.98, 95% CI 1.33-6.66; p=0.008).Assessment of the C1q-binding capacity of DSA appears to be useful in identifying stable lung transplant recipients at high risk of lung allograft loss., Competing Interests: Conflict of interest: H. Mal reports personal fees from Roche, Boehringer and CSL Behring, outside the submitted work. Support statement: This study was funded by Vaincre la Mucoviscidose (VLM). Funding information for this article has been deposited with the Crossref Funder Registry., (Copyright ©ERS 2018.)

Mucosal-associated invariant T (MAIT) cells are semi-invariant Vα7.2 + CD161 high CD4 - T cells that recognize microbial riboflavin precursor derivatives such as 5-OP-RU presented by MR1. Human MAIT cells are abundant in adult blood, but there are very few in cord blood. We longitudinally studied Vα7.2 + CD161 high T cell and related subset levels in infancy and after cord blood transplantation. We show that Vα7.2 + and Vα7.2 - CD161 high T cells are generated early during gestation and likely share a common prenatal developmental program. Among cord blood Vα7.2 + CD161 high T cells, the minority recognizing MR1:5-OP-RU display a TRAV/TRBV repertoire very similar to adult MAIT cells. Within a few weeks of life, only the MR1:5-OP-RU reactive Vα7.2 + CD161 high T cells acquire a memory phenotype. Only these cells expand to form the adult MAIT pool, diluting out other Vα7.2 + CD161 high and Vα7.2 - CD161 high populations, in a process requiring at least 6 years to reach adult levels. Thus, the high clonal size of adult MAIT cells is antigen-driven and likely due to the fine specificity of the TCRαβ chains recognizing MR1-restricted microbial antigens., (© 2018 Ben Youssef et al.)

The human leukocyte antigen-A2 (HLA-A2)-restricted zinc transporter 8 186-194 (ZnT8 186-194 ) and other islet epitopes elicit interferon-γ secretion by CD8 + T cells preferentially in type 1 diabetes (T1D) patients compared with controls. We show that clonal ZnT8 186-194 -reactive CD8 + T cells express private T cell receptors and display equivalent functional properties in T1D and healthy individuals. Ex vivo analyses further revealed that CD8 + T cells reactive to ZnT8 186-194 and other islet epitopes circulate at similar frequencies and exhibit a predominantly naïve phenotype in age-matched T1D and healthy donors. Higher frequencies of ZnT8 186-194 -reactive CD8 + T cells with a more antigen-experienced phenotype were detected in children versus adults, irrespective of disease status. Moreover, some ZnT8 186-194 -reactive CD8 + T cell clonotypes were found to cross-recognize a Bacteroides stercoris mimotope. Whereas ZnT8 was poorly expressed in thymic medullary epithelial cells, variable thymic expression levels of islet antigens did not modulate the peripheral frequency of their cognate CD8 + T cells. In contrast, ZnT8 186-194 -reactive cells were enriched in the pancreata of T1D patients versus nondiabetic and type 2 diabetic individuals. Thus, islet-reactive CD8 + T cells circulate in most individuals but home to the pancreas preferentially in T1D patients. We conclude that the activation of this common islet-reactive T cell repertoire and progression to T1D likely require defective peripheral immunoregulation and/or a proinflammatory islet microenvironment., (Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Mucosal-associated invariant T (MAIT) cells are unconventional CD3 + CD161 high T lymphocytes that recognize vitamin B2 (riboflavin) biosynthesis precursor derivatives presented by the MHC-I related protein, MR1. In humans, their T cell receptor is composed of a Vα7.2-Jα33/20/12 chain, combined with a restricted set of Vβ chains. MAIT cells are very abundant in the liver (up to 40% of resident T cells) and in mucosal tissues, such as the lung and gut. In adult peripheral blood, they represent up to 10% of circulating T cells, whereas they are very few in cord blood. This large number of MAIT cells in the adult likely results from their gradual expansion with age following repeated encounters with riboflavin-producing microbes. Upon recognition of MR1 ligands, MAIT cells have the capacity to rapidly eliminate bacterially infected cells through the production of inflammatory cytokines (IFNγ, TNFα, and IL-17) and cytotoxic effector molecules (perforin and granzyme B). Thus, MAIT cells may play a crucial role in antimicrobial defense, in particular at mucosal sites. In addition, MAIT cells have been implicated in diseases of non-microbial etiology, including autoimmunity and other inflammatory diseases. Although their participation in various clinical settings has received increased attention in adults, data in children are scarce. Due to their innate-like characteristics, MAIT cells might be particularly important to control microbial infections in the young age, when long-term protective adaptive immunity is not fully developed. Herein, we review the data showing how MAIT cells may control microbial infections and how they discriminate pathogens from commensals, with a focus on models relevant for childhood infections.

The development of cancer and chronic infections is facilitated by many subversion mechanisms, among which enhanced expression of immune checkpoints molecules, such as programmed death-1 (PD-1) and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), on exhausted T cells. Recently, immune checkpoint inhibitors have shown remarkable efficiency in the treatment of a number of cancers. However, expression of immune checkpoints on natural killer (NK) cells and its functional consequences on NK cell effector functions are much less explored. In this review, we focus on the current knowledge on expression of various immune checkpoints in NK cells, how it can alter NK cell-mediated cytotoxicity and cytokine production. Dissecting the role of these inhibitory mechanisms in NK cells is critical for the full understanding of the mode of action of immunotherapies using checkpoint inhibitors in the treatment of cancers and chronic infections., Competing Interests: The authors declare no conflict of interest.

Recent advances in technologies such as high density array-based genotyping, DNA and RNA deep sequencing, expression quantitative-trait loci mapping, epigenome analyses, and new computational strategies, have introduced drastic shifts into our understanding of major histocompatibility complex (MHC) association with immune-mediated diseases. Here, we review the most exciting findings in this field. We show how the fine characterization of structural features and expression levels of MHC alleles, posttranslational or environmental modifications of HLA-bound peptides, and epistatic interactions with non-HLA genes, has made it possible not only to provide mechanistic explanations for MHC associations with immune-mediated diseases but also to help choose relevant therapeutic targets., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Programmed Death-1 (PD-1), an inhibitory receptor expressed by activated lymphocytes, is involved in regulating T- and B-cell responses. PD-1 and its ligands are exploited by a variety of cancers to facilitate tumor escape through PD-1-mediated functional exhaustion of effector T cells. Here, we report that PD-1 is upregulated on Natural Killer (NK) cells from patients with Kaposi sarcoma (KS). PD-1 was expressed in a sub-population of activated, mature CD56dimCD16pos NK cells with otherwise normal expression of NK surface receptors. PD-1pos NK cells from KS patients were hyporesponsive ex vivo following direct triggering of NKp30, NKp46 or CD16 activating receptors, or short stimulation with NK cell targets. PD-1pos NK cells failed to degranulate and release IFNγ, but exogenous IL-2 or IL-15 restored this defect. That PD-1 contributed to NK cell functional impairment and was not simply a marker of dysfunctional NK cells was confirmed in PD-1-transduced NKL cells. In vitro, PD-1 was induced at the surface of healthy control NK cells upon prolonged contact with cells expressing activating ligands, i.e. a condition mimicking persistent stimulation by tumor cells. Thus, PD-1 appears to plays a critical role in mediating NK cell exhaustion. The existence of this negative checkpoint fine-tuning NK activation highlights the possibility that manipulation of the PD-1 pathway may be a strategy for circumventing tumor escape not only from the T cell-, but also the NK-cell mediated immune surveillance.

A paradigm in transplantation states that graft-infiltrating T cells are largely non-alloreactive "bystander" cells. However, the origin and specificity of allograft T cells over time has not been investigated in detail in animals or humans. Here, we use polychromatic flow cytometry and high throughput TCR sequencing of serial biopsies to show that gut-resident T cell turnover kinetics in human intestinal allografts are correlated with the balance between intra-graft host-vs-graft (HvG) and graft-vs-host (GvH) reactivities and with clinical outcomes. In the absence of rejection, donor T cells were enriched for GvH-reactive clones that persisted long-term in the graft. Early expansion of GvH clones in the graft correlated with rapid replacement of donor APCs by the recipient. Rejection was associated with transient infiltration by blood-like recipient CD28+ NKG2D Hi CD8+ alpha beta T cells, marked predominance of HvG clones, and accelerated T cell turnover in the graft. Ultimately, these recipient T cells acquired a steady state tissue-resident phenotype, but regained CD28 expression during rejections. Increased ratios of GvH to HvG clones were seen in non-rejectors, potentially mitigating the constant threat of rejection posed by HvG clones persisting within the tissue-resident graft T cell population.

Allogeneic hematopoietic stem cell transplantation (AHSCT) is a curative treatment for a wide variety of hematological diseases. In 30% of the cases, a geno-identical donor is available. Any other situation displays some level of human leukocyte antigen (HLA) incompatibility between donor and recipient. Deleterious effects of anti-HLA immunization have long been recognized in solid organ transplant recipients. More recently, anti-HLA immunization was shown to increase the risk of primary graft failure (PGF), a severe complication of AHSCT that occurs in 3-4% of matched unrelated donor transplantation and up to 15% in cord blood transplantation and T-cell depleted haplo-identical stem cell transplantation. Rates of PGF in patients with DSA were reported to be between 24 and 83% with the highest rates in haplo-identical and cord blood transplantation recipients. This led to the recommendation of anti-HLA antibody screening to detect donor-specific antibodies (DSA) in recipients prior to AHSCT. In this review, we highlight the role of anti-HLA antibodies in AHSCT and the mechanisms that may lead to PGF in patients with DSA, and discuss current issues in the field.

Despite effective targeted therapy acting on KIT and PDGFRA tyrosine kinases, gastrointestinal stromal tumors (GIST) escape treatment by acquiring mutations conveying resistance to imatinib mesylate (IM). Following the identification of NKp30-based immunosurveillance of GIST and the off-target effects of IM on NK cell functions, we investigated the predictive value of NKp30 isoforms and NKp30 soluble ligands in blood for the clinical response to IM. The relative expression and the proportions of NKp30 isoforms markedly impacted both event-free and overall survival, in two independent cohorts of metastatic GIST. Phenotypes based on disbalanced NKp30B/NKp30C ratio (ΔBC low ) and low expression levels of NKp30A were identified in one third of patients with dismal prognosis across molecular subtypes. This ΔBC low blood phenotype was associated with a pro-inflammatory and immunosuppressive tumor microenvironment. In addition, detectable levels of the NKp30 ligand sB7-H6 predicted a worse prognosis in metastatic GIST. Soluble BAG6, an alternate ligand for NKp30 was associated with low NKp30 transcription and had additional predictive value in GIST patients with high NKp30 expression. Such GIST microenvironments could be rescued by therapy based on rIFN-α and anti-TRAIL mAb which reinstated innate immunity.

Background: Durable HIV-1 remission after interruption of combined antiretroviral therapy (ART) has been reported in some adults who started treatment during primary infection; however, whether long-term remission in vertically infected children is possible was unknown. We report a case of a young adult perinatally infected with HIV-1 with viral remission despite long-term treatment interruption., Methods: The patient was identified in the ANRS EPF-CO10 paediatric cohort among 100 children infected with HIV perinatally who started ART before 6 months of age. HIV RNA viral load and CD4 cell counts were monitored from birth. Ultrasensitive HIV RNA, peripheral blood mononuclear cell (PBMC)-associated HIV DNA, HIV-specific T-cell responses (ie, production of cytokines and capacity to suppress HIV infection), reactivation of the CD4 cell reservoir (measured by p24 ELISA and HIV RNA in supernatants upon phytohaemagglutinin activation of purified CD4 cells), and plasma concentrations of antiretroviral drugs were assessed after 10 years of documented control off therapy., Findings: The infant was born in 1996 to a woman with uncontrolled HIV-1 viraemia and received zidovudine-based prophylaxis for 6 weeks. HIV RNA and DNA were not detected 3 days and 14 days after birth. HIV DNA was detected at 4 weeks of age. HIV RNA reached 2·17× 10(6) copies per mL at 3 months of age and ART was started. HIV RNA was undetectable 1 month later. ART was discontinued by the family at some point between 5·8 and 6·8 years of age. HIV RNA was undetectable at 6·8 years of age and ART was not resumed. HIV RNA has remained below 50 copies per mL and CD4 cell counts stable through to 18·6 years of age. After 11·5 years of control off treatment, HIV RNA was below 4 copies per mL and HIV DNA was 2·2 log10 copies per 10(6) PBMCs. The HLA genotype showed homozygosity at several loci (A*2301-, B*1503/4101, C*0210/0802, DRB1*1101-, and DQB1*0602-). HIV-specific CD8 T-cell responses and T-cell activation were weak., Interpretation: Findings from this case suggest that long-term HIV-1 remission is possible in perinatally infected children who receive treatment early, with characteristics similar to those reported in adult HIV post-treatment controllers. Further studies are needed to understand the mechanisms associated with HIV remission and whether early treatment of infected children might favour the conditions needed to achieve HIV control after treatment discontinuation., Funding: Agence de recherche ANRS (France Recherche Nord & Sud Sida-HIV Hépatites)., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

We retrospectively analyzed the impact of HLA-DPB1 mismatches in a large cohort of 1342 French patients who underwent 10/10 HLA-matched unrelated HSCT. A significant impact of HLA-DPB1 allelic mismatches (2 vs 0) was observed in severe acute GVHD (aGVHDIII-IV) (risk ratio (RR)=1.73, confidence interval (CI) 95% 1.09-2.73, P=0.019) without impact on OS, TRM, relapse and chronic GVHD (cGVHD). According to the T-cell epitope 3 (TCE3)/TCE4 HLA-DPB1 disparity algorithm, 37.6% and 58.4% pairs had nonpermissive HLA-DPB1, respectively. TCE3 and TCE4 disparities had no statistical impact on OS, TRM, relapse, aGVHD and cGVHD. When TCE3/TCE4 disparities were analyzed in the graft-vs-host or host-vs-graft (HVG) direction, only a significant impact of TCE4 nonpermissive disparities in the HVG direction was observed on relapse (RR=1.34, CI 95% 1.00-1.80, P=0.048). In conclusion, this French retrospective study shows an adverse prognosis of HLA-DPB1 mismatches (2 vs 0) on severe aGVHD and of nonpermissive TCE4 HVG disparities on relapse after HLA-matched 10/10 unrelated HSCT.

Past genome-wide association studies (GWAS) involving individuals with AIDS have mainly identified associations in the HLA region. Using the latest software, we imputed 7 million single-nucleotide polymorphisms (SNPs)/indels of the 1000 Genomes Project from the GWAS-determined genotypes of individuals in the Genomics of Resistance to Immunodeficiency Virus AIDS nonprogression cohort and compared them with those of control cohorts. The strongest signals were in MICA, the gene encoding major histocompatibility class I polypeptide-related sequence A (P = 3.31 × 10(-12)), with a particular exonic deletion (P = 1.59 × 10(-8)) in full linkage disequilibrium with the reference HCP5 rs2395029 SNP. Haplotype analysis also revealed an additive effect between HLA-C, HLA-B, and MICA variants. These data suggest a role for MICA in progression and elite control of human immunodeficiency virus type 1 infection., (© The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

A nonsynonymous SNP +1858C/T (rs2476601) in the protein tyrosine phosphatase, nonreceptor type 22(PTPN22) gene leading to Arg 620 Trp substitution is known to be associated with susceptibility to type 1 diabetes (T1D) and several other autoimmune diseases. We studied this polymorphism in 145 T1D patients and 210 healthy controls from North India. The minor allele +1858T was observed to be significantly increased among patients as compared to healthy controls (2.76% vs 0.5%, P = 0.027, OR = 5.93; 95% CI = 1.4-24.8). The association was also observed at the level of heterozygous C/T genotype (5.5% vs 0.95%, P = 0.026, OR = 6.07; 95% CI = 1.43-25.6). The T allele and C/T genotype were predominantly found among patients who were positive for both glutamic acid decarboxylase 65 (GAD65) and insulin antigen 2 (IA2) autoantibodies and showed significantly increased frequencies (10%, P = 0.034, OR = 11.67; 95% CI = 1.58-84.1 and 20%, P = 0.031, OR = 13.0; 95% CI = 1.66-97.5, respectively) as compared to patients negative for these autoantibodies (0.95% and 1.9%, respectively). The results suggest that the PTPN22+1858T allele is positively associated with T1D in the North Indian population., (© 2014 John Wiley & Sons Ltd.)

The relevance of tissue specificity of microvascular endothelial cells (MECs) in the response to inflammatory stimuli and sensitivity to immune cell-mediated injury is not well defined. We hypothesized that such MEC characteristics might shape their interaction with NK cells through the use of different adhesion molecules and NK cell receptor ligands or the release of different soluble factors and render them more or less vulnerable to NK cell injury during autoimmune vasculitis, such as granulomatosis with polyangiitis (GPA). To generate a comprehensive expression profile of human MECs of renal, lung, and dermal tissue origin, we characterized, in detail, their response to inflammatory cytokines and to proteinase 3, a major autoantigen in GPA, and analyzed the effects on NK cell activation. In this study, we show that renal MECs were more susceptible than lung and dermal MECs to the effect of inflammatory signals, showing upregulation of ICAM-1 and VCAM-1 on their surface, as well as release of CCL2, soluble fractalkine, and soluble VCAM-1. Proteinase 3-stimulated renal and lung MECs triggered CD107a degranulation in control NK cell. Notably, NK cells from GPA patients expressed markers of recent in vivo activation (CD69, CD107a), degranulated more efficiently than did control NK cells in the presence of renal MECs, and induced direct killing of renal MECs in vitro. These results suggest that, upon inflammatory conditions in GPA, renal MECs may contribute to the recruitment and activation of NK cells in the target vessel wall, which may participate in the necrotizing vasculitis of the kidney during this disease.

Beyond cancer-cell intrinsic factors, the immune status of the host has a prognostic impact on patients with cancer and influences the effects of conventional chemotherapies. Metastatic melanoma is intrinsically immunogenic, thereby facilitating the search for immune biomarkers of clinical responses to cytotoxic agents. Here, we show that a multi-tyrosine kinase inhibitor, sorafenib, upregulates interleukin (IL)-15Rα in vitro and in vivo in patients with melanoma, and in conjunction with natural killer (NK) group 2D (NKG2D) ligands, contributes to the Th1 polarization and accumulation of peripheral CD4(+)NKG2D(+) T cells. Hence, the increase of blood CD4(+)NKG2D(+) T cells after two cycles of sorafenib (combined with temozolomide) was associated with prolonged survival in a prospective phase I/II trial enrolling 63 patients with metastatic melanoma who did not receive vemurafenib nor immune checkpoint-blocking antibodies. In contrast, in metastatic melanoma patients treated with classical treatment modalities, this CD4(+)NKG2D(+) subset failed to correlate with prognosis. These findings indicate that sorafenib may be used as an "adjuvant" molecule capable of inducing or restoring IL-15Rα/IL-15 in tumors expressing MHC class I-related chain A/B (MICA/B) and on circulating monocytes of responding patients, hereby contributing to the bioactivity of NKG2D(+) Th1 cells.

The major histocompatibility complex class I related chain (MIC) is a stress-inducible protein modulating the function of immune natural killer (NK) cells, a major leukocyte subset involved in proper trophoblast invasion and spiral artery remodeling. Aim of the study was to evaluate whether upregulation of soluble MIC (sMIC) may reflect immune disorders associated to vascular pregnancy diseases (VPD). sMIC was more frequently detected in the plasma of women with a diagnostic of VPD (32%) than in normal term-matched pregnancies (1.6%, P < 0.0001), with highest prevalence in intrauterine fetal death (IUDF, 44%) and vascular intrauterine growth restriction (IUGR, 39%). sMIC levels were higher in preeclampsia (PE) than in IUFD (P < 0.01) and vascular IUGR (P < 0.05). sMIC detection was associated with bilateral early diastolic uterine notches (P = 0.037), thrombocytopenia (P = 0.03), and high proteinuria (P = 0.03) in PE and with the vascular etiology of IUGR (P = 0.0038). Incubation of sMIC-positive PE plasma resulted in downregulation of NKG2D expression and NK cell-mediated IFN-γ production in vitro. Our work thus suggests that detection of sMIC molecule in maternal plasma may constitute a hallmark of altered maternal immune functions that contributes to vascular disorders that complicate pregnancy, notably by impairing NK-cell mediated production of IFN-γ, an essential cytokine favoring vascular modeling.

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disease characterized by a lymphocytic exocrinopathy. However, patients often have evidence of systemic autoimmunity, and they are at markedly increased risk for the development of non- Hodgkin's lymphoma. Similar to other autoimmune disorders, a strong interferon (IFN) signature is present among subsets of pSS patients, although the precise etiology remains uncertain. NCR3/NKp30 is a natural killer (NK)-specific activating receptor regulating the cross talk between NK and dendritic cells and type II IFN secretion. We performed a case-control study of genetic polymorphisms of the NCR3/NKp30 gene and found that rs11575837 (G>A) residing in the promoter was associated with reduced gene transcription and function as well as protection to pSS. We also demonstrated that circulating levels of NCR3/NKp30 were significantly increased among pSS patients compared with controls and correlated with higher NCR3/NKp30 but not CD16-dependent IFN-γ secretion by NK cells. Excess accumulation of NK cells in minor salivary glands correlated with the severity of the exocrinopathy. B7H6, the ligand of NKp30, was expressed by salivary epithelial cells. These findings suggest that NK cells may promote an NKp30-dependent inflammatory state in salivary glands and that blockade of the B7H6/NKp30 axis could be clinically relevant in pSS.

Aim: Glutamic acid decarboxylase (GAD) and/or islet antigen-2 (IA-2) autoantibodies (ab) are present in 90% of patients at the onset of type 1 diabetes (T1D). Few studies have shown that they may persist in the long-term. We analysed the frequency of GADab and IA-2ab and the factors associated with their persistency in patients with long-lasting T1D., Methods: This cross-sectional study included 430 adult patients with T1D of at least 10-year duration, consecutively seen over one year. GADab and IA-2ab were determined by radio-binding assays. Autoantibodies to thyroperoxydase, gastric parietal cells and transglutaminase were assessed in 418 patients, and HLA DRB1 genotyping in 359. Parameters associated with the persistency of antibodies were studied by multivariate analysis., Results: Median age at diagnosis of T1D was 12 years, and median diabetes duration was 19 years. Extrapancreatic autoimmunity was present in 38% of the patients, and associated autoimmune diseases in 21%. GADab and/or IA-2ab were found in 56% of the patients, and in 32% in those with more than 25-year diabetes duration. GADab were more frequent than IA-2ab. Female sex, an older age at diagnosis, and a shorter duration of diabetes were independently associated with the presence of ab. The same factors and the DR3 allele were associated with GADab, while only diabetes duration and the DR4 allele were associated with IA-2ab., Conclusion: In a large proportion of the patients with T1D, the long-term persistency of diabetes-associated antibodies allows aetiological diagnosis, even far from the onset of hyperglycaemia., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

NKG2D mediates an important costimulatory pathway in CD8 T cells. In HIV infection, the authors found that NKG2D expression on both total CD8 and HIV-specific CD8 T cells was significantly lower in viremic patients than in HIV controllers. Antiretroviral therapy partially restored NKG2D expression on HIV-specific CD8 T cells. The authors observed a negative correlation between the respective expression levels of CD38 and NKG2D on total CD8 and HIV-specific CD8 T cells. The maintenance of NKG2D expression on CD8 T cells in HIV controllers may contribute to better cell function.

Invariant natural killer T (iNKT) cells can experimentally dissociate GVL from graft-versus-host-disease (GVHD). Their role in human conventional allogeneic hematopoietic stem cell transplantation (HSCT) is unknown. Here, we analyzed the post-HSCT recovery of iNKT cells in 71 adult allografted patients. Results were compared with conventional T- and NK-cell recovery and correlated to the occurrence of GVHD, relapse, and survival. We observed that posttransplantation iNKT cells, likely of donor origin, recovered independently of T and NK cells in the first 90 days after HSCT and reached greater levels in recipient younger than 45 years (P = .003) and after a reduced-intensity conditioning regimen (P = .03). Low posttransplantation iNKT/T ratios (ie, < 10(-3)) were an independent factor associated with the occurrence of acute GVHD (aGVHD; P = .001). Inversely, reaching iNKT/T ratios > 10(-3) before day 90 was associated with reduced nonrelapse mortality (P = .009) without increased risk of relapse and appeared as an independent predictive factor of an improved overall survival (P = .028). Furthermore, an iNKT/T ratio on day 15 > 0.58 × 10(-3) was associated with a 94% risk reduction of aGVHD. These findings provide a proof of concept that early postallogeneic HSCT iNKT cell recovery can predict the occurrence of aGVHD and an improved overall survival.

Objectives: Churg-Strauss syndrome (CSS) is a necrotising vasculitis of small vessels in which oligoclonally expanded TCR Vβ CD8+ effector memory T cells populations (TEM) may be involved in vasculitic damage. The aim of this study was to assess the functional role of CD8+ T cells in CSS patients by flow cytometry analysis of membrane expression of cytotoxic markers NKG2D and CD107a., Methods: Immunostaining of peripheral T cells and effector memory lymphocytes (TEM) from CSS patients and controls was performed by gating CD28 and CD45RA in the CD8+NKG2D+ and CD4+NKG2D+ populations. CD107a expression was evaluated in both whole CD8+ and CD4+ and the TEM cells by gating CD62 and CD45RA following polyclonal stimulation., Results: NKG2D expression was shifted toward the CD8+CD28- fraction of T cells in CSS patients compared to healthy controls (56.1±25.8% versus 17.2±7.3%, respectively, p=0.002). CD8+Vβ+ expanded T cells showed a significantly increased expression of NKG2D compared to the whole CD8+ T cell population (91.4±1.9% versus 79.7±3.8%, respectively, p=0.015). Moreover the CD8+ population from CSS upregulates CD107a on its surface upon polyclonal stimulation in a significantly higher proportion than healthy subjects (26.2±10.8% versus 8.2±2.9%, p=0.0031) and the majority CD8+ CD107+ cells from CSS patients showed a TEM phenotype compared to controls (64.8±4.9% vs. 19.8±2.9, respectively, p<0.001)., Conclusions: In CSS, CD8+ TEM lymphocytes show markers of cytotoxic activity, which suggests a role for these cells in vasculitic damage.