Studying antigen-specific T cells through a streamlined, whole blood-based extracellular approach.

Techniques currently used for the study of antigen-specific T-cell responses are either poorly informative or require a heavy workload. Consequently, many perspectives associated with the broader study of such approaches remain mostly unexplored in translational research. However, these could benefit many fields including but not limited to infectious diseases, oncology, and vaccination. Herein, the main objective of this work was to develop a standardized flow cytometry-based approach that would combine ease of use together with a relevant study of antigen-specific T-cell responses so that they could be more often included in clinical research. To this extent, a streamlined approach relying on 1/ the use of whole blood instead of peripheral blood mononuclear cells and 2/ solely based on the expression of extracellular activation-induced markers (AIMs), called whole blood AIM (WAIM), was developed and further compared to more conventional techniques such as enzyme-linked immunospot (ELISpot) and flow cytometry-based intracellular cytokine staining (ICS). Based on a cohort of 20 individuals receiving the COVID-19 mRNA vaccine and focusing on SARS-CoV-2 and cytomegalovirus (CMV)-derived antigen T-cell-specific responses, a significant level of correlation between the three techniques was found. Based on the use of whole blood and on the expression of extracellular activation-induced markers (CD154, CD137, and CD107a), the WAIM technique appears to be very simple to implement and yet allows interesting patient stratification capabilities as the chosen combination of extracellular markers exhibited higher orthogonality than cytokines that are commonly considered in ICS (IFN-γ, TNF-α, and IL-2).

Simple gene signature to assess murine fibroblast polarization.

We provide an original multi-stage approach identifying a gene signature to assess murine fibroblast polarization. Prototypic polarizations (inflammatory/fibrotic) were induced by seeded mouse embryonic fibroblasts (MEFs) with TNFα or TGFß1, respectively. The transcriptomic and proteomic profiles were obtained by RNA microarray and LC-MS/MS. Gene Ontology and pathways analysis were performed among the differentially expressed genes (DEGs) and proteins (DEPs). Balb/c mice underwent daily intradermal injections of HOCl (or PBS) as an experimental murine model of inflammation-mediated fibrosis in a time-dependent manner. As results, 1456 and 2215 DEGs, and 289 and 233 DEPs were respectively found in MEFs in response to TNFα or TGFß1, respectively. Among the most significant pathways, we combined 26 representative genes to encompass the proinflammatory and profibrotic polarizations of fibroblasts. Based on principal component analysis, this signature deciphered baseline state, proinflammatory polarization, and profibrotic polarization as accurately as RNA microarray and LC-MS/MS did. Then, we assessed the gene signature on dermal fibroblasts isolated from the experimental murine model. We observed a proinflammatory polarization at day 7, and a mixture of a proinflammatory and profibrotic polarizations at day 42 in line with histological findings. Our approach provides a small-size and convenient gene signature to assess murine fibroblast polarization.

A potential role of preexisting inflammation in the development of acute myelopathy following CAR T-cell therapy for diffuse large B-cell lymphoma.

The event of anti-CD19 chimeric antigen receptor (CAR)-T therapy inducing serious neurotoxicity in patients with diffuse large B-cell lymphoma (DLBCL) is recognized; however, the patterns of symptoms and severity vary greatly from patient to patient. We report an exceptional presentation of acute myelopathy in a refractory DLBCL following successful CAR-T treatment along with grade 3 cytokine release syndrome (CRS) and neurotoxicity. The patient was initiated on high-dose methylprednisolone (MPS) resulting in rapid improvement of neurological symptoms. Yet the myelopathy patient (MP) experienced severe lower limb motor deficit, and a subsequent spinal cord MRI revealed myelopathy with a sensory level at segment T2. Multimodal therapy consisting of MPS, intravenous immunoglobulin and anakinra therapy resulted in complete reversal of myelopathy condition and the patient remained cancer free. The assessment of time trends of serum cytokines at baseline and post CAR-T infusion in MP compared to other 4 DLBCL complete responder patients with varying degree of CRS following CAR-T infusion, suggested pre-existing baseline inflammatory conditions in MP with altered levels of cytokines. These findings, if corroborated by similar case studies, have the potential to generate novel insights into the manifestation of myelopathy following CAR-T therapy and the successful clinical management of such complications.

Impact of Tacrolimus Daily Dose Limitation in Renal Transplant Recipients Expressing CYP3A5: A Retrospective Study.

The pharmacokinetic variability of tacrolimus can be partly explained by CYP3A5 activity. Our objective was to evaluate a tacrolimus sparing policy on renal graft outcome according to CYP3A5 6986A>G genetic polymorphism. This retrospective study included 1114 recipients with a median follow-up of 6.3 years. Genotyping of the 6986A>G allelic variant corresponding to CYP3A5*3 was systematically performed. One year after transplantation, tacrolimus blood trough concentration (C0) target range was 5-7 ng/mL. However, daily dose was capped to 0.10 mg/kg/day regardless of the CYP3A5 genotype. A total 208 CYP3A5*1/- patients were included. Despite a higher daily dose, CYP3A5*1/- recipients exhibited lower C0 during follow-up (p < 0.01). Multivariate analysis did not show any significant influence of CYP3A5*1/- genotype (HR = 0.70, 0.46-1.07, p = 0.10) on patient-graft survival. Glomerular Filtration Rate (GFR) decline was significantly lower for the CYP3A5*1/- group (p = 0.02). The CYP3A5*1/- genotype did not significantly impact the risk of biopsy-proven acute rejection (BPAR) (HR = 1.01, 0.68-1.49, p = 0.97) despite significantly lower C0. Based on our experience, a strategy of tacrolimus capping is associated with a better GFR evolution in CYP3A5*1/- recipients without any significant increase of BPAR incidence. Our study raised some issues about specific therapeutic tacrolimus C0 targets for CYP3A5*1/- patients and suggests to set up randomized control studies in this specific population.

Metabolic and immunological phenotype of rare lipomatoses: Dercum's disease and Roch-Leri mesosomatic lipomatosis.

CONTEXT: Dercum's disease (DD) and Roch-Leri mesosomatic lipomatosis (LMS) are rare and poorly characterized diseases. The clinical presentation combines multiple lipomas, painful in DD in contrast with LMS, without lipoatrophy. OBJECTIVE: To identify any specific metabolic and immune phenotype of DD and LMS. DESIGN AND PATIENTS: This monocentric retrospective study included 46 patients: 9 DD, 11 LMS, 18 lean and 8 obese controls. Metabolic and immunohematological characteristics of each group were compared. RESULTS: The median age of the patients was similar in the 3 groups (31 years). The number of women, and of basophils, and CD3+, CD4+ and CD8+ T lymphocytes was significantly higher in the DD versus the LMS group, without any difference of the metabolic parameters. Weight, BMI, blood pressure, gamma-GT, leptin, fasting insulin and C-peptide levels, fat mass percentage, and intra/total abdominal fat ratio were significantly higher in each lipomatosis group compared with the lean group. Compared with the lean group, the DD group had significantly higher fasting blood glucose, LDL-cholesterol, platelets, leukocytes, basophils, and a lower NK cell count, whereas the LMS group had a significantly lower rate of CD3, CD4, and CD8 lymphocytes. Compared with the obese controls, basophils remained higher in DD and T lymphocytes subpopulations lower in LMS groups. CONCLUSION: DD and LMS show a common background of obesity and metabolic phenotype, but a distinct immunohematological profile characterized by a higher number of basophils in DD patients, an inflammatory profile that could contribute to pain. T lymphocyte depletion was present in LMS. These findings could offer specific therapeutic opportunities, especially for painful DD.

Monitoring CAR T-cells using flow cytometry.

BACKGROUND: Chimeric antigen receptor (CAR) T-cell therapy is considered as a major scientific breakthrough in cancer immunotherapy. The success of adoptive CAR T-cell therapy for cancer has inspired researchers to expand indications into the area of solid tumors, autoimmune and infectious diseases. The most important factors influencing outcome and durability of the response after infusion of CAR T-cell are proliferation and persistence of this cell subset. It becomes therefore important to detect easily and monitor circulating CAR T-cells into blood samples. Approaches such as quantitative PCR (qPCR) or flow cytometry have been developed. The aim of this study was to set up and optimize a reachable flow cytometry technique using labeled CD19 protein for the measurement of CAR T-cells in infusion bag and patient's blood. METHODS: Patients receiving Yescarta in Cell Therapy Unit (Department of hematology, Lille university hospital, France) between April and October 2019 and healthy volunteers were included to set up the flow cytometry technique. RESULTS AND CONCLUSIONS: We assessed feasibility in clinic and suitability to routine workload of a flow cytometry technique to follow CAR T-cells in infusion bag and patient's blood. With only a few manual steps, the present protocol allows the technician to perform this technique among other routine tasks, meaning a time to results of <2 hr after sample reception. We were also able to assess CAR T-cell heterogenity in terms of CD4+ and CD8+ T lymphocytes within the subset. Moreover, this technique allows monitoring of both authority approved CD19 CAR T-cell.

Clinico-Biological Features and Clonal Hematopoiesis in Patients with Severe COVID-19.

Advanced age or preexisting comorbidities have been characterized as risk factors for severe coronavirus disease 2019 (COVID-19) cases requiring hospitalization and intensive care. In recent years, clonal hematopoiesis (CH) of indeterminate potential (CHIP) has emerged as a risk factor for chronic inflammatory background and subsequent aging-associated diseases. The purpose of this study was to identify biological factors (particularly leukocyte subtypes and inflammatory markers) associated with a risk of clinical deterioration (i.e., orotracheal intubation (OTI)) and to determine whether CH was likely to influence clinical and biological behavior in patients with severe COVID-19 requiring hospitalization. Here, we describe clinical and biological features, including the screening of CHIP mutants in a well-annotated cohort of 122 hospitalized patients with a laboratory-confirmed diagnosis of COVID-19 (55% requiring OTI). We showed that elevated white blood cell counts, especially neutrophils and high C-reactive protein (CRP) levels at admission, were associated with an increased requirement of OTI. We noticed a high prevalence of CH (25%, 38%, 56%, and 82% of patients aged <60 years, 60-70 years, 70-80 years, and >80 years) compared to a retrospective cohort of patients free of hematological malignancy explored with the same pipelines (10%, 21%, 37%, and 44%). However, the existence of CH did not significantly impact clinical outcome, including OTI or death, and did not correlate with other laboratory findings.

Moderate-to-severe eosinophilia induced by treatment with immune checkpoint inhibitors: 37 cases from a national reference center for hypereosinophilic syndromes and the French pharmacovigilance database.

A better understanding of immune-related adverse events is essential for the early detection and appropriate management of these phenomena. We conducted an observational study of cases recorded at the French reference center for hypereosinophilic syndromes and in the French national pharmacovigilance database. Thirty-seven reports of eosinophilia induced by treatment with immune checkpoint inhibitors (ICIs) were included. The median [range] time to the absolute eosinophil count (AEC) peak was 15 [4─139] weeks. The median AEC was 2.7 [0.8─90.9] G/L. Eosinophil-related manifestations were reported in 21 of the 37 cases (57%). If administered, corticosteroids were always effective (n = 10 out of 10). Partial or complete remission of eosinophilia was obtained in some patients not treated with corticosteroids, after discontinuation (n = 12) or with continuation (n = 4) of the ICI. The AEC should be monitored in ICI-treated patients. If required by oncologic indications, continuation of ICI may be an option in asymptomatic hypereosinophilic patients, and in corticosteroid responders.

Compatibility at amino acid position 98 of MICB reduces the incidence of graft-versus-host disease in conjunction with the CMV status.

Graft-versus-host disease (GVHD) and cytomegalovirus (CMV)-related complications are leading causes of mortality after unrelated-donor hematopoietic cell transplantation (UD-HCT). The non-conventional MHC class I gene MICB, alike MICA, encodes a stress-induced polymorphic NKG2D ligand. However, unlike MICA, MICB interacts with the CMV-encoded UL16, which sequestrates MICB intracellularly, leading to immune evasion. Here, we retrospectively analyzed the impact of mismatches in MICB amino acid position 98 (MICB98), a key polymorphic residue involved in UL16 binding, in 943 UD-HCT pairs who were allele-matched at HLA-A, -B, -C, -DRB1, -DQB1 and MICA loci. HLA-DP typing was further available. MICB98 mismatches were significantly associated with an increased incidence of acute (grade II-IV: HR, 1.20; 95% CI, 1.15 to 1.24; P < 0.001; grade III-IV: HR, 2.28; 95% CI, 1.56 to 3.34; P < 0.001) and chronic GVHD (HR, 1.21; 95% CI, 1.10 to 1.33; P < 0.001). MICB98 matching significantly reduced the effect of CMV status on overall mortality from a hazard ratio of 1.77 to 1.16. MICB98 mismatches showed a GVHD-independent association with a higher incidence of CMV infection/reactivation (HR, 1.84; 95% CI, 1.34 to 2.51; P < 0.001). Hence selecting a MICB98-matched donor significantly reduces the GVHD incidence and lowers the impact of CMV status on overall survival.

Ustekinumab Serum Trough Levels May Identify Suboptimal Responders to Ustekinumab in Crohn's Disease.

INTRODUCTION: The aim of this study was to evaluate the association between serum ustekinumab (UST) trough levels and response to induction and maintenance UST treatment in refractory Crohn's Disease (CD) patients. METHODS: We performed a prospective study including CD patients who received UST from September 2015 to January 2017. Patients received 90 mg of UST subcutaneously at weeks 0, 4, and 12, then every 8 weeks. Two cohorts of patients were analyzed: an induction cohort and a maintenance cohort. We evaluated clinical, biological, and imaging/endoscopic response to UST treatment. UST trough levels and anti-UST antibodies were dosed at weeks 12 and 28 in the induction cohort, and at a single time point in the maintenance cohort. RESULTS: Forty-nine patients were enrolled in the maintenance cohort. Mean concentrations of UST were 1.88 ± 1.40 µg/mL. UST trough levels were not significantly different in patients with or without clinical, biological, or imaging/endoscopic responses to UST treatment (p > 0.11). Twenty-three consecutive patients were included in the induction cohort. At week 12, mean UST concentrations were 1.45 ± 1.15 µg/mL. Patients with a biological response to UST treatment had significant higher serum UST trough concentration (median 1.72 µg/mL) than non-responders (median 0.56 µg/mL, p = 0.02). A UST trough level ≥ 1.10 µg/mL at week 12 was associated with a biological response to UST treatment at 6 months. CONCLUSION: UST trough levels were associated with a biological response at the end of the induction phase. In patients with low levels of UST, optimization treatment may be necessary to obtain a sustained response.

"Idiopathic Eosinophilic Vasculitis": Another Side of Hypereosinophilic Syndrome? A Comprehensive Analysis of 117 Cases in Asthma-Free Patients.

BACKGROUND: The absence of asthma may rule out a diagnosis of eosinophilic granulomatosis with polyangiitis in patients with hypereosinophilic syndrome (HES) and features of vasculitis. OBJECTIVE: To describe eosinophilic vasculitis (EoV) as a possible manifestation of HES in asthma-free patients. METHODS: We screened our hospital database and the literature for patients with HES who met the following 4 criteria: (1) histopathological or clinical features of EoV (biopsy-proven vasculitis with predominant eosinophilic infiltration of the vessel wall and/or features of vasculitis with tissue and/or blood hypereosinophilia [absolute eosinophil count >1.5 G/L]); (2) no other obvious causes of reactive eosinophilia, organ damage, and vasculitis; (3) the absence of antineutrophil cytoplasmic antibodies; and (4) the absence of current asthma. RESULTS: Ten of our 83 (12%) asthma-free patients with HES and 107 additional cases in the literature met the criteria for EoV. After a critical analysis of the patients' clinical and laboratory characteristics and outcomes, we identified 41 cases of single-organ EoV (coronary arteritis, n = 29; temporal arteritis, n = 8; cerebral vasculitis, n = 4). Of the remaining 76 patients with EoV, the most frequent manifestations (>10%) were cutaneous vasculitis (56%), peripheral neuropathy (24%), thromboangiitis obliterans-like disease (16%), fever (13%), central nervous system involvement (13%), deep venous thrombosis (12%), and nonasthma lung manifestations (12%). Blood hypereosinophilia more than 1.5 G/L was observed in 79% of patients, and necrotizing vasculitis was observed in 44%. CONCLUSIONS: Our results suggest that idiopathic EoV (HES-associated vasculitis) can be classified as an eosinophilic-rich, necrotizing, systemic form of vasculitis that affects vessels of various sizes in asthma-free patients.

Characterization of the novel HLA-DRB1*14:207 allele by sequencing-based typing.

HLA-DRB1*14:207 differs from HLA-DRB1*14:54:01:01 by one nucleotide substitution at codon 140 in exon 3.

Donor-derived CD4+/CCR7+ T-cell impact on acute GVHD incidence following haplo-HCT after reduced intensity conditioning and posttransplant cyclophosphamide.

In previous studies, we and others observed in patients undergoing HLA-matched hematopoietic cell transplantation that high proportion of donor-derived CD4+/CCR7+ T cells were associated with an increased risk of acute GVHD without any interference in relapse incidence. We investigated the impact of donor-derived CD4+/CCR7+ T cells on patient outcome in haploidentical settings where posttransplant cyclophosphamide is used. We analyzed T-cell subsets in grafts of 29 adult patients who underwent first haploidentical transplant following reduced intensity conditioning. The median CD4+/CCR7+ subset proportion was 69.2% among donor CD4+ T cells. With a median follow-up of 28.1 months (range: 11.0-44.3), 16 patients (55%) developed acute GVHD; this includes 5 patients with grade 3 acute GVHD. Fifty-four percent of patients who received > 69.2% of CD4+/CCR7+ T cells and 12% of patients who received < 69.2% CD4+/CCR7+ T cells developed acute GVHD (p = 0.028). In multivariate analysis, a high proportion of CD4+/CCR7+ T cells was the only factor that impacted acute GVHD (HR = 4.925, 95% CI [1.020-23.775], p = 0,047) with no impact on overall survival. Our results confirm the impact of a high proportion of CD4+/CCR7+ T cells on acute GVHD incidence in patients undergoing haploidentical transplant despite the use of posttransplant cyclophosphamide.

HLA-DRB3/4/5 mismatches are associated with increased risk of acute GVHD in 10/10 matched unrelated donor hematopoietic cell transplantation.

Matching for HLA-A, -B, -C, and -DRB1 loci (8/8 match) is currently the gold standard for unrelated donor hematopoietic cell transplantation (HCT). In Europe, patients are also matched at the HLA-DQB1 loci (10/10 match). However, there is increasing evidence that matching at HLA-DRB3/4/5 loci may help to lower transplant-related morbidity and mortality. We therefore investigated the impact of HLA-DRB3/4/5 mismatches on outcomes in 1975 patients who received a first 10/10 matched unrelated donor (MUD) HCT in France from 2000 to 2012 for a hematological malignancy. High-resolution typing was performed at HLA-A, -B, -C, -DRB1, -DQB1, -DPB1, and -DRB3/4/5 loci for all donor/recipient pairs. Compared with DRB3/4/5-matched pairs, patients who received a MUD HCT from a DRB3/4/5 mismatched donor had a significantly increased risk of grade II-IV acute graft-versus-host disease (aGVHD) (Adjusted Hazard Ratio (HR) 1.43 (1.07 to 1.90)) associated with lower graft-versus-host disease-free and relapse-free survival (GRFS) (Adjusted HR 1.20 (1.02 to 1.42)). Conversely, we observed no differences in terms of chronic GVHD, nonrelapse mortality, relapse and overall survival. However, we believe that patients stand to benefit from DRB3/4/5 loci being considered for unrelated donor selection to improve GRFS and then quality of life after unrelated HCT.

A standardized flow cytometry procedure for the monitoring of regulatory T cells in clinical trials.

BACKGROUND: Quantification of regulatory T cells (Tregs) is crucial in immunomonitoring in clinical trials as this cell population has been shown to be involved in a wide range of diseases, including cancers, autoimmune diseases, infections, and allergies. Human Tregs are defined as CD4+ CD25+ CD127low FoxP3+ cells, and the standardization of their staining by flow cytometry is a challenge, especially in multicenter clinical trials, notably because of the intracellular location of FoxP3. METHOD: A flow cytometry staining procedure was settled and standardized to measure human Tregs in peripheral whole blood using precoated dried antibodies in ready-to-use tubes. It was compared with reference methods and implemented and validated to be suitable with different cytometer platforms. RESULTS: The standardized protocol developed with dried antibodies and reduced volumes of whole blood allows an optimal identification of Tregs. Compared with classical staining procedure, it reduces the number of steps required, in a very fast and simple technique. The accuracy of the method was confirmed by a multicenter comparison with different cytometer brands. CONCLUSIONS: Our results highlight the reliability of this high-standard protocol that could become a reference method for the monitoring of Tregs in clinical trials. © 2018 International Clinical Cytometry Society.

Altered B lymphocyte homeostasis and functions in systemic sclerosis.

Beyond the production of autoantibodies, B-cells are thought to play a role in systemic sclerosis (SSc) by secreting proinflammatory/profibrotic cytokines. B-cells are a heterogeneous population with different subsets distinguished by their phenotypes and cytokine production. Data about B-cell subsets, cytokine production and intracellular pathways leading to this production are scarce in SSc. The aim of our study was to describe B-cell homeostasis, activation, proliferation, cytokine production in B-cells and serum and B-cell intracellular signaling pathways in SSc. We hypothezided that B-cell homeostasis and cytokine production were altered in SSc and could be explained by serum cytokine as well as by intracellular signaling pathway abnormalities. Forty SSc patients and 20 healthy controls (HC) were prospectively included. B-cell subsets were determined by flow cytometry using CD19, CD21, CD24, CD38, CD27, IgM and IgD. CD25, CD80, CD95, HLA-DR were used to assess B-cell activation. Intracellular production of IL-10 and IL-6 were assessed by flow cytometry after TLR9 and CD40 stimulation. IL-6, IL-10, Ki67, Bcl2 mRNA were quantified in B-cells. Cytokine production was also assessed in sera and supernatants of B-cell culture, using a multiplex approach. Signaling pathways were studied through phosphorylation of mTOR, ERK, STAT3, STAT5 using a flow cytometry approach. We found that SSc patients exhibited an altered peripheral blood B-cell subset distribution, with decreased memory B-cells but increased proportion of naive and CD21LoCD38Lo B-cell subsets. We observed an increased expression of activation markers (CD80, CD95, HLA-DR) on some B-cell subsets, mainly the memory B-cells. Secretion of IL-6, BAFF and CXCL13 were increased in SSc sera. There was no correlation between the peripheral blood B-cell subsets and the serum concentrations of these cytokines. After stimulation, we observed a lower proportion of IL-10 and IL-6 producing B-cells in SSc. Finally, we observed a significant decrease of mTOR phosphorylation in SSc patient B-cells. In conclusion, we observed an altered B-cell homeostasis in SSc patients compared to HC. Memory B-cells were both decreased and activated in patients. IL-10 producing B-cells were decreased in SSc. This decrease was associated with an alteration of mTOR phosphorylation in B-cells. Conversely, there was no correlation between serum cytokine profile and B-cell homeostasis alterations.