Efficacy and safety of rituximab in myasthenia gravis: a French multicentre real-life study.

BACKGROUND AND PURPOSE: Fifteen percent of patients with myasthenia gravis (MG) are refractory to conventional treatment. Case reports and a few studies show probable benefit of rituximab in these cases. Our objective was to assess the efficacy and the safety of rituximab in patients with MG, in a multicentric real-life study. METHOD: Inclusion criteria were: age > 18 years; MG with anti-acetylcholine receptor (AChR) antibodies, anti-muscle-specific kinase (MuSk) antibodies or significant decrement after repetitive nerve stimulation; Myasthenia Gravis Foundation of America (MGFA) class >II; refractory or steroid-dependent MG; and treatment with rituximab. Efficacy was assessed at 6 months using the MGFA-post-intervention status (PIS) score, the myasthenic muscle score (MMS) and the number of patients receiving steroids <10 mg/day. Data on adverse events were collected. RESULTS: Twenty-nine patients were included: 20 with anti-AChR MG, five with anti-MuSK MG and four with seronegative MG. MGFA-PIS score was improved or better (improved, minimal manifestations or remission) in 86.2% of patients after 6 months of treatment (P < 0.0001). The mean MMS increased from 68.8 to 83.1 (P < 0.0001). A decrease in steroid dosage (<10 mg/day) was effective in 57.9% of treated patients. In all, 42.8% of patients experienced adverse events: infections (21.4% of patients); infusion reaction (7%); bradycardia (3.7%); and cytopenia (7%). CONCLUSION: The present study demonstrates the efficacy and safety of rituximab in patients with MG. Additional studies remain necessary to determine the role of rituximab in the pharmacopeia of MG treatment and to establish precise recommendations for the infusion protocol.

Genome-Wide Association Study of Acute Renal Graft Rejection.

Acute renal rejection is a major risk factor for chronic allograft dysfunction and long-term graft loss. We performed a genome-wide association study to detect loci associated with biopsy-proven acute T cell-mediated rejection occurring in the first year after renal transplantation. In a discovery cohort of 4127 European renal allograft recipients transplanted in eight European centers, we used a DNA pooling approach to compare 275 cases and 503 controls. In an independent replication cohort of 2765 patients transplanted in two European countries, we identified 313 cases and 531 controls, in whom we genotyped individually the most significant single nucleotide polymorphisms (SNPs) from the discovery cohort. In the discovery cohort, we found five candidate loci tagged by a number of contiguous SNPs (more than five) that was never reached in iterative in silico permutations of our experimental data. In the replication cohort, two loci remained significantly associated with acute rejection in both univariate and multivariate analysis. One locus encompasses PTPRO, coding for a receptor-type tyrosine kinase essential for B cell receptor signaling. The other locus involves ciliary gene CCDC67, in line with the emerging concept of a shared building design between the immune synapse and the primary cilium.

Marine phospholipids: The current understanding of their oxidation mechanisms and potential uses for food fortification.

There is a growing interest in using marine phospholipids (PL) as ingredient for food fortification due to their numerous health benefits. However, the use of marine PL for food fortification is a challenge due to the complex nature of the degradation products that are formed during the handling and storage of marine PL. For example, nonenzymatic browning reactions may occur between lipid oxidation products and primary amine group from phosphatidylethanolamine or amino acid residues that are present in marine PL. Therefore, marine PL contain products from nonenzymatic browning and lipid oxidation reactions, namely, Strecker aldehydes, pyrroles, oxypolymers, and other impurities that may positively or negatively affect the oxidative stability and quality of marine PL. This review was undertaken to provide the industry and academia with an overview of the current understanding of the quality changes taking place in PL during their production and their storage as well as with regards to their utilization for food fortification.

CMV infection in the donor and increased kidney graft loss: impact of full HLA-I mismatch and posttransplantation CD8(+) cell reduction.

Despite a large body of literature, the impact of chronic cytomegalovirus (CMV) infection in donor on long-term graft survival remains unclear, and factors modulating the effect of CMV infection on graft survival are presently unknown. In this retrospective study of 1279 kidney transplant patients, we analyzed long-term graft survival and evolution of CD8(+) cell population in donors and recipients by CMV serology and antigenemia status. A positive CMV serology in the donor was an independent risk factor for graft loss, especially among CMV-positive recipients (R(+) ). Antigenemia was not a risk factor for graft loss and kidneys from CMV-positive donors remained associated with poor graft survival among antigenemia-free recipients. Detrimental impact of donor's CMV seropositivity on graft survival was restricted to patients with full HLA-I mismatch, suggesting a role of CD8(+) cells. In R(+) patients with positive CMV antigenemia during the first year, CD8(+) cell count did not increase at 2 years posttransplantation, in contrast to R(-) recipients. In addition, marked CD8(+) -cell decrease was a risk factor of graft failure in these patients. This study identifies HLA-I full mismatch and a decrease of CD8(+) cell count at 2 years as important determinants of CMV-associated graft loss.

The effect of concomitant gradient fields on diffusion tensor imaging.

Concomitant gradient fields are transverse magnetic field components that are necessarily present to satisfy Maxwell's equations when magnetic field gradients are utilized in magnetic resonance imaging. They can have deleterious effects that are more prominent at lower static fields and/or higher gradient strengths. In diffusion tensor imaging schemes that employ large gradients that are not symmetric about a refocusing radiofrequency pulse (unlike Stejskal-Tanner, which is symmetric), concomitant fields may cause phase accrual that could corrupt the diffusion measurement. Theory predicting the error from this dephasing is described and experimentally validated for both Reese twice-refocused and split gradient single spin-echo diffusion gradient schemes. Bias in apparent diffusion coefficient values was experimentally found to worsen with distance from isocenter and with increasing duration of gradient asymmetry in both a phantom and in the brain. The amount of error from concomitant gradient fields depends on many variables, including the diffusion gradient pattern, pulse sequence timing, maximum effective gradient amplitude, static magnetic field strength, voxel size, slice distance from isocenter, and partial Fourier fraction. A prospective correction scheme that can reduce concomitant gradient errors is proposed and verified for diffusion imaging.

Initial experience with vNOTES hysterectomy for benign conditions in a French university hospital.

Background: Natural orifice transluminal endoscopic surgery by the vaginal route (vNOTES) is a new approach to performing hysterectomy. Clinical outcomes must be evaluated in centres that have started performing this technique. Objectives: To compare operative outcomes between vNOTES hysterectomy and laparoscopic hysterectomy during the introduction of the vNOTES approach in a teaching hospital. Material and Methods: A retrospective study was conducted from November 2019 to May 2021 at a French academic hospital in Marseille. The included patients underwent total hysterectomy for benign indications by vNOTES or conventional laparoscopy. Main outcome measures: Operative time, uterus weight, intraoperative complications, and postoperative complications according to the Clavien-Dindo classification. Results: Eighty-six patients underwent hysterectomy according to the selected criteria: 36 procedures were performed by vNOTES and 50 by laparoscopy. The mean operative time was shorter in the vNOTES group than in the laparoscopy group [116 min versus 149 min; p=0.003]. The mean uterus weight was not different between the vNOTES group and the laparoscopy group (238g versus 281g; p=0.572). Laparo-conversion occurred in one case in the vNOTES group (2.7%) and three cases in the laparoscopy group (3.4%). One Grade III postoperative complication occurred in the laparoscopy group, and no severe complication occurred in the vNOTES group. Conclusion: Operative outcomes of the vNOTES hysterectomy were favourable and support good feasibility without additional morbidity compared to laparoscopy. What is new?: During the introduction period of the vNOTES hysterectomy technique in a teaching hospital, reassuring operative outcomes and a low rate of complications were observed.

Monitoring of in-vitro ultrasonic stimulation of cells by numerical modeling.

Ultrasound stimulation of living tissues is a promising technique that can be safely applied for regenerative treatments. However, the ultrasound-induced mechanotransduction is still not well understood because of the large number of parameters involved at different scales and their difficult experimental accessibility. In this context, in-vitro studies may help to gain insight into the interaction between ultrasound and cells. Nevertheless, to conduct a reliable analysis of ultrasound effects on cell culture, the monitoring of the acoustic intensity delivered to the cells is of prime interest. Thanks to the development of an innovative custom experimental set-up inspired from ultrasound stimulation of bone regeneration conditions, major disturbing phenomena such as multiple reflections and standing wave formation inside the Petri dish are eliminated. Thus, the level of ultrasound stimulation, especially, in terms of spatial average temporal average intensity (ISATA), delivered to the cells can be monitored. Then, to properly estimate the level of ultrasound stimulation, a finite element model representing the experimental in-vitro configuration is developed. The numerical model manages on capturing the characteristics of the experimentally measured acoustic intensity distribution as illustrated by the experimental and numerical ISATA values of 42.3 and 45.8 mW/cm2 respectively, i.e. a relative difference of 8%. The numerical model would therefore allow exploring data inaccessible to experimental measurement and parametric studies to be carried out and facilitates the investigation of different virtual experimental configurations.

IMM-BCP-01, a patient-derived anti-SARS-CoV-2 antibody cocktail, is active across variants of concern including Omicron BA.1 and BA.2.

Monoclonal antibodies are an efficacious therapy against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, rapid viral mutagenesis led to escape from most of these therapies, outlining the need for an antibody cocktail with a broad neutralizing potency. Using an unbiased interrogation of the memory B cell repertoire of patients with convalescent COVID-19, we identified human antibodies with broad antiviral activity in vitro and efficacy in vivo against all tested SARS-CoV-2 variants of concern, including Delta and Omicron BA.1 and BA.2. Here, we describe an antibody cocktail, IMM-BCP-01, that consists of three patient-derived broadly neutralizing antibodies directed at nonoverlapping surfaces on the SARS-CoV-2 Spike protein. Two antibodies, IMM20184 and IMM20190, directly blocked Spike binding to the ACE2 receptor. Binding of the third antibody, IMM20253, to its cryptic epitope on the outer surface of RBD altered the conformation of the Spike Trimer, promoting the release of Spike monomers. These antibodies decreased Omicron SARS-CoV-2 infection in the lungs of Syrian golden hamsters in vivo and potently induced antiviral effector response in vitro, including phagocytosis, ADCC, and complement pathway activation. Our preclinical data demonstrated that the three-antibody cocktail IMM-BCP-01 could be a promising means for preventing or treating infection of SARS-CoV-2 variants of concern, including Omicron BA.1 and BA.2, in susceptible individuals.

Mothers without HLA antibodies before transplantation have a low risk of alloimmunization post-transplantation.

Human leukocyte antigen antibodies (HLA Abs) are associated with poor renal graft outcome. We selected 134 first kidney transplant recipients without HLA Ab (LABScreen® Luminex) before transplantation despite previous allogeneic exposure whether through blood transfusion (BT) and/or pregnancy (PR). We screened these patients for HLA Ab post-transplantation (yearly) and determined the risk of HLA Ab and donor-specific antibody (DSA) appearance according to BT/PR in a univariate and a multivariate model. Among the 134 patients (43 males/91 females), 56 were BT+/PR-, 41 BT-/PR+ and 37 BT+/PR+. Median delay between last PR or BT and transplantation were 25.9 years (0.5-47.8) and 8 months (0.8-128.0), respectively. Median number of PR and BT were 2 (1-11) and 3 units (1-28), respectively. After transplantation (median follow-up: 47.5 months), 13 patients (9.7%) had HLA Ab and 10 DSA, mainly directed against class II HLA (HLA Ab: 10/13, DSA: 9/10). The risk of HLA Ab and DSA appearance was significantly lower in patients with PR before transplantation (P = 0.032 and P = 0.009, respectively). The risk of DSA appearance (hazard ratio = 0.17, P = 0.027) remained significantly lower after adjustment on donor age, acute rejection and number of class I/II HLA mismatches. In conclusion, we show that parous women non-immunized are at low risk of HLA Ab production after transplantation.

Adoptive transfer of minor histocompatibility antigen-specific T lymphocytes eradicates leukemia cells without causing graft-versus-host disease.

Adoptive transfer of T cells reactive to minor histocompatibility antigens has the unmatched ability to eradicate malignant hematopoietic cells. Unfortunately, its use is hampered by the associated graft-versus-host disease. The critical issue of a possible dissociation of the antileukemic effect and graft-versus-host disease by targeting specific minor histocompatibility antigens remains unresolved because of the unknown nature and number of minor histocompatibility antigens necessary or sufficient to elicit anti-leukemic activity and graft-versus-host disease. We found that injection of T lymphocytes primed against a single major histocompatibility complex class I-restricted immunodominant minor histocompatibility antigen (B6dom1) caused no graft-versus-host disease but produced a curative anti-leukemic response. Avoidance of graft-versus-host disease required that no other host-reactive T cells be co-injected with T cells primed with B6dom1. Here we show that effective and non-toxic immunotherapy of hematologic malignancies can be achieved by targeting a single immunodominant minor histocompatibility antigen.

Rapid microscopic fractional anisotropy imaging via an optimized linear regression formulation.

Water diffusion anisotropy in the human brain is affected by disease, trauma, and development. Microscopic fractional anisotropy (µFA) is a diffusion MRI (dMRI) metric that can quantify water diffusion anisotropy independent of neuron fiber orientation dispersion. However, there are several different techniques to estimate µFA and few have demonstrated full brain imaging capabilities within clinically viable scan times and resolutions. Here, we present an optimized spherical tensor encoding (STE) technique to acquire µFA directly from the 2nd order cumulant expansion of the powder averaged dMRI signal obtained from direct linear regression (i.e. diffusion kurtosis) which requires fewer powder-averaged signals than other STE fitting techniques and can be rapidly computed. We found that the optimal dMRI parameters for white matter µFA imaging were a maximum b-value of 2000 s/mm2 and a ratio of STE to LTE tensor encoded acquisitions of 1.7 for our system specifications. We then compared two implementations of the direct regression approach to the well-established gamma model in 4 healthy volunteers on a 3 Tesla system. One implementation used mean diffusivity (D) obtained from a 2nd order fit of the cumulant expansion, while the other used a linear estimation of D from the low b-values. Both implementations of the direct regression approach showed strong linear correlations with the gamma model (ρ = 0.97 and ρ = 0.90) but mean biases of -0.11 and - 0.02 relative to the gamma model were also observed, respectively. All three µFA measurements showed good test-retest reliability (ρ ≥ 0.79 and bias = 0). To demonstrate the potential scan time advantage of the direct approach, 2 mm isotropic resolution µFA was demonstrated over a 10 cm slab using a subsampled data set with fewer powder-averaged signals that would correspond to a 3.3-min scan. Accordingly, our results introduce an optimization procedure that has enabled nearly full brain µFA in only several minutes.

[Endometrial receptivity in assisted reproductive techniques: An aspect to investigate in embryo implantation failure]. / La réceptivité endométriale en aide médicale à la procréation : Une piste à ne pas oublier devant un échec d'implantation.

Infertility affects between 8 and 12% of reproductive-age couples worldwide. Despite improvements in assisted reproductive techniques (ART), live birth rates are still limited. In clinical practice, imaging and microscopy are currently widely used, but their diagnostic effectiveness remains limited. In research, the emergence of innovative techniques named OMICS would improve the identification of the implantation window, while progressing in the understanding of the pathophysiological mechanisms involved in embryo implantation failures. To date, transcriptomic analysis seems to be the most promising approach in clinical research. The objective of this review is to present the results obtained with the different approaches available in clinical practice and in research to assess endometrial receptivity in patients undergoing ART.

Unbiased interrogation of memory B cells from convalescent COVID-19 patients reveals a broad antiviral humoral response targeting SARS-CoV-2 antigens beyond the spike protein.

Patients who recover from SARS-CoV-2 infections produce antibodies and antigen-specific T cells against multiple viral proteins. Here, an unbiased interrogation of the anti-viral memory B cell repertoire of convalescent patients has been performed by generating large, stable hybridoma libraries and screening thousands of monoclonal antibodies to identify specific, high-affinity immunoglobulins (Igs) directed at distinct viral components. As expected, a significant number of antibodies were directed at the Spike (S) protein, a majority of which recognized the full-length protein. These full-length Spike specific antibodies included a group of somatically hypermutated IgMs. Further, all but one of the six COVID-19 convalescent patients produced class-switched antibodies to a soluble form of the receptor-binding domain (RBD) of S protein. Functional properties of anti-Spike antibodies were confirmed in a pseudovirus neutralization assay. Importantly, more than half of all of the antibodies generated were directed at non-S viral proteins, including structural nucleocapsid (N) and membrane (M) proteins, as well as auxiliary open reading frame-encoded (ORF) proteins. The antibodies were generally characterized as having variable levels of somatic hypermutations (SHM) in all Ig classes and sub-types, and a diversity of VL and VH gene usage. These findings demonstrated that an unbiased, function-based approach towards interrogating the COVID-19 patient memory B cell response may have distinct advantages relative to genomics-based approaches when identifying highly effective anti-viral antibodies directed at SARS-CoV-2.

Immune depression syndrome following human spinal cord injury (SCI): a pilot study.

Experimental spinal cord injury (SCI) has been identified to trigger a systemic, neurogenic immune depression syndrome. Here, we have analyzed fluctuations of immune cell populations following human SCI by FACS analysis. In humans, a rapid and drastic decrease of CD14+ monocytes (<50% of control level), CD3+ T-lymphocytes (<20%, P<0.0001) and CD19+ B-lymphocytes (<30%, P=0.0009) and MHC class II (HLA-DR)+ cells (<30%, P<0.0001) is evident within 24 h after spinal cord injury reaching minimum levels within the first week. CD15+ granulocytes were the only leukocyte subpopulation not decreasing after SCI. A contributing, worsening effect of high dose methylprednisolone cannot be excluded with this pilot study. We demonstrate that spinal cord injury is associated with an early onset of immune suppression and secondary immune deficiency syndrome (SCI-IDS). Identification of patients suffering spinal cord injury as immune compromised is a clinically relevant, yet widely underappreciated finding.

Active plasmonic devices via electron spin.

A class of active terahertz devices that operate via particle plasmon oscillations is introduced for ensembles consisting of ferromagnetic and dielectric micro-particles. By utilizing an interplay between spin-orbit interaction manifesting as anisotropic magnetoresistance and the optical distance between ferromagnetic particles, a multifaceted paradigm for device design is demonstrated. Here, the phase accumulation of terahertz radiation across the device is actively modulated via the application of an external magnetic field. An active plasmonic directional router and an active plasmonic cylindrical lens are theoretically explored using both an empirical approach and finite-difference time-domain calculations. These findings are experimentally supported.

A plasmonic random composite with atypical refractive index.

We present a material composite consisting of randomly oriented elements governed by non-resonant interactions. By exploiting near-field plasmonic interaction in a dense ensemble of subwavelength-sized dielectric and metallic particles, we reveal that the group refractive index of the composite can be increased to be larger than the effective refractive indices of constituent metallic and dielectric parent composites. These findings introduce a new class of engineered photonic materials having customizable and atypical optical constants.

Anti-CD25 antibodies affect cytokine synthesis pattern of human dendritic cells and decrease their ability to prime allogeneic CD4+ T cells.

Anti-CD25 monoclonal antibodies are widely used in clinical transplantation to prevent acute allograft rejection. Although their effects on T lymphocytes have been extensively studied, their impact on human dendritic cells (DC) has never been reported. Furthermore, the role of the IL-2 in DC functions has not yet been fully elucidated. In this study, we confirm that the stimulation of human monocyte-derived DC with LPS strongly induced the expression of CD25 and that LPS-matured DC also expressed the beta and gamma chain of the IL-2R. We also showed that adding anti-CD25 monoclonal antibodies to LPS induced a decrease in IL-12, IL-1, TNF-alpha, IL-6, and IFN-gamma production and an increase in IL-10 synthesis by DC compared with stimulation with LPS alone. Furthermore, we showed that these modifications diminished the T helper priming ability of DC and polarized the alloimmune response toward TH2. In contrast, humanized anti-CD25 monoclonal antibodies did not affect the up-regulation of CD86, CD80, CD83, HLADR, or CD40 induced upon LPS stimulation. Taken together, this study discloses some previously unrecognized effects of anti-CD25 monoclonal antibodies on DC that may contribute to their clinical efficacy. In addition, this study also shed some light on the role of the IL-2 in human DC activation.

Anti-CD25 antibodies decrease the ability of human dendritic cells to prime allogeneic CD4 T cells.

Anti-CD25 monoclonal antibodies are largely used in clinical transplantation to prevent acute allograft rejection episodes. Although their effects on T lymphocytes have been extensively studied, their impact on human dendritic cells (DCs) has been less reported. Furthermore, the role of the interleukin-2 in DC functions has not yet been fully elucidated. In this study, we observed that stimulation of human monocyte-derived DCs with lipopolysa ccharide or CD40L strongly induced the expression of CD25. We showed that pretreatment of DC with anti-CD25 diminished their ability to prime T-helper cells. In contrast, humanized anti-CD25 monoclonal antibodies did not affect the up-regulation of CD86, CD80, CD83, HLA-DR, or CD40 induced by lipopolysaccharide stimulation. This study supported previously unrecognized effects of anti-CD25 monoclonal antibodies on DCs that may contribute to their clinical efficacy.

Mycophenolic Acid Inhibits p38 Mitogen-Activated Protein Kinase in Human Monocyte-Derived Dendritic Cells Stimulated by Lipopolysaccharide.

Dendritic cell (DC) maturation, a crucial stage in the immune response, can be induced by various stimuli, such as lipopolysaccharide (LPS). Maturation signals trigger up-regulation of costimulatory molecule expression, increasing the ability of DCs to prime T helper cells. We and others have previously reported that mycophenolic acid (MPA) inhibits DC maturation and activation. However, the mechanisms remain unknown. The primary effect of MPA is inhibition of inosine monophosphate dehydrogenase (IMPDH), an enzyme involved in the de novo synthesis of guanosine nucleotide. The process of DC maturation is highly dependent on mitogen-activated protein kinase (MAPK) phosphorylation, especially p38MAPK. We therefore decided to study whether MPA affects these processes. Human monocyte-derived DCs were activated by LPS in the presence or absence of MPA. To assess whether the depletion of guanine affected p38MAPK phosphorylation, increasing doses of exogenous guanosine were added before stimulation. The results by flow cytometry showed that MPA inhibited p38MAPK phosphorylation by 25%. Interestingly, exogenous guanosine did not reverse the MPA inhibition. Our results suggested that MPA inhibits p38MAPK activity independent of IMPDH in human DCs. This effect of MPA may explain its capacity to inhibit maturation marker expression on DCs.

Induction of porcine regulatory cells by mycophenolic Acid-treated dendritic cells.

Tolerance induction in murine allogeneic transplantation is relatively easy, often by induction of regulatory T cells (Treg). Unfortunately, the implementation of these models in clinical situations has not yielded reliable protocols of tolerance induction in humans. Our project sought to create a preclinical model of tolerance induction in large animals. Our current efforts seek to induce and characterize porcine Treg, obtaining dendritic cells (DC) able to preferentially stimulate them. DCs were differentiated from blood monocytes with porcine recombinant interleukin-4 (IL-4) and granulocyte-macrophage colony-stimulating factor (GM-CSF) for 6 days. These DCs were then stimulated by human CD40 ligand-transfected L cells with or without mycophenolic acid (MPA) for 48 hours. We analyzed surface marker expression, cytokine synthesis, and ability to stimulate allogeneic peripheral blood mononuclear cells (PBMC). The porcine lymphocytes underwent 4 rounds of 1-week stimulation with allogeneic DC treated or not with MPA. At the end of this coculture we analyzed their capacity to suppress allogeneic PBMC proliferation induced by mature DC. Our results showed that porcine DCs pretreated with MPA display a low expression of B7 costimulatory molecules, produce low levels of IL-12, and induce weak proliferation of allogeneic lymphocytes. Moreover, after 4 rounds of stimulation with MPA-treated DCs, PBMCs were able to inhibit an alloreactive response. These preliminary results suggested induction of a regulatory T-cell population that we are currently seeking to characterize.