Fetal cardiac and neonatal cerebral hemodynamics and oxygen metabolism in transposition of the great arteries.

OBJECTIVES: Hemodynamic abnormalities and brain development disorders have been reported previously in fetuses and infants with transposition of the great arteries and intact ventricular septum (TGA-IVS). A ventricular septal defect (VSD) is thought to be an additional risk factor for adverse neurodevelopment, but literature describing this population is sparse. The objectives of this study were to assess fetal cardiac hemodynamics throughout pregnancy, to monitor cerebral hemodynamics and oxygen metabolism in neonates, and to compare these data between patients with TGA-IVS, those with TGA-VSD and age-matched controls. METHODS: Cardiac hemodynamics were assessed in TGA-IVS and TGA-VSD fetuses and compared with healthy controls matched for gestational age (GA) during three periods: ≤ 22 + 5 weeks (GA1), 27 + 0 to 32 + 5 weeks (GA2) and ≥ 34 + 5 weeks (GA3). Left (LVO), right (RVO) and combined (CVO) ventricular outputs, ductus arteriosus flow (DAF, sum of ante- and retrograde flow in systole and diastole), diastolic DAF, transpulmonary flow (TPF) and foramen ovale diameter were measured. Aortic (AoF) and main pulmonary artery (MPAF) flows were derived as a percentage of CVO. Fetal middle cerebral artery and umbilical artery (UA) pulsatility indices (PI) were measured and the cerebroplacental ratio (CPR) was derived. Bedside optical brain monitoring was used to measure cerebral hemoglobin oxygen saturation (SO2 ) and an index of microvascular cerebral blood flow (CBFi ), along with peripheral arterial oxygen saturation (SpO2 ), in TGA-IVS and TGA-VSD neonates. Using hemoglobin (Hb) concentration measurements, these parameters were used to derive cerebral oxygen delivery and extraction fraction (OEF), as well as an index of cerebral oxygen metabolism (CMRO2i ). These data were acquired in the early preoperative period (within 3 days after birth and following balloon atrial septostomy) and compared with those of age-matched healthy controls, and repeat measurements were collected before discharge when vital signs were stable. RESULTS: LVO was increased in both TGA groups compared with controls throughout pregnancy. Compared with controls, TPF was increased and diastolic DAF was decreased in TGA-IVS fetuses throughout pregnancy, but only during GA1 and GA2 in TGA-VSD fetuses. Compared with controls, DAF was decreased in TGA-IVS fetuses throughout pregnancy and in TGA-VSD fetuses at GA2 and GA3. At GA2, AoF was higher in TGA-IVS and TGA-VSD fetuses than in controls, while MPAF was lower. At GA3, RVO and CVO were higher in the TGA-IVS group than in the TGA-VSD group. In addition, UA-PI was lower at GA2 and CPR higher at GA3 in TGA-VSD fetuses compared with TGA-IVS fetuses. Within 3 days after birth, SpO2 and SO2 were lower in both TGA groups than in controls, while Hb, cerebral OEF and CMRO2i were higher. Preoperative SpO2 was also lower in TGA-VSD neonates than in those with TGA-IVS. From preoperative to predischarge periods, SpO2 and OEF increased in both TGA groups, but CBFi and CMRO2i increased only in the TGA-VSD group. During the predischarge period, SO2 was higher in TGA-IVS than in TGA-VSD neonates, while CBFi was lower. CONCLUSIONS: Fetal cardiac and neonatal cerebral hemodynamic/metabolic differences were observed in both TGA groups compared with controls. Compared to those with TGA-IVS, fetuses with TGA-VSD had lower RVO and CVO in late gestation. A higher level of preoperative hypoxemia was observed in the TGA-VSD group. Postsurgical cerebral adaptive mechanisms probably differ between TGA groups. Patients with TGA-VSD have a specific physiology that warrants further study to improve neonatal care and neurodevelopmental outcome. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Agonist anti-ChemR23 mAb reduces tissue neutrophil accumulation and triggers chronic inflammation resolution.

Resolution of inflammation is elicited by proresolving lipids, which activate GPCRs to induce neutrophil apoptosis, reduce neutrophil tissue recruitment, and promote macrophage efferocytosis. Transcriptional analyses in up to 300 patients with Inflammatory Bowel Disease (IBD) identified potential therapeutic targets mediating chronic inflammation. We found that ChemR23, a GPCR targeted by resolvin E1, is overexpressed in inflamed colon tissues of severe IBD patients unresponsive to anti-TNFα or anti-α4ß7 therapies and associated with significant mucosal neutrophil accumulation. We also identified an anti-ChemR23 agonist antibody that induces receptor signaling, promotes macrophage efferocytosis, and reduces neutrophil apoptosis at the site of inflammation. This ChemR23 mAb accelerated acute inflammation resolution and triggered resolution in ongoing chronic colitis models, with a significant decrease in tissue lesions, fibrosis and inflammation-driven tumors. Our findings suggest that failure of current IBD therapies may be associated with neutrophil infiltration and that ChemR23 is a promising therapeutic target for chronic inflammation.

Near-Sun observations of an F-corona decrease and K-corona fine structure.

Remote observations of the solar photospheric light scattered by electrons (the K-corona) and dust (the F-corona or zodiacal light) have been made from the ground during eclipses1 and from space at distances as small as 0.3 astronomical units2-5 to the Sun. Previous observations6-8 of dust scattering have not confirmed the existence of the theoretically predicted dust-free zone near the Sun9-11. The transient nature of the corona has been well characterized for large events, but questions still remain (for example, about the initiation of the corona12 and the production of solar energetic particles13) and for small events even its structure is uncertain14. Here we report imaging of the solar corona15 during the first two perihelion passes (0.16-0.25 astronomical units) of the Parker Solar Probe spacecraft13, each lasting ten days. The view from these distances is qualitatively similar to the historical views from ground and space, but there are some notable differences. At short elongations, we observe a decrease in the intensity of the F-coronal intensity, which is suggestive of the long-sought dust free zone9-11. We also resolve the fine-scale plasma structure of very small eruptions, which are frequently ejected from the Sun. These take two forms: the frequently observed magnetic flux ropes12,16 and the predicted, but not yet observed, magnetic islands17,18 arising from the tearing-mode instability in the current sheet. Our observations of the coronal streamer evolution confirm the large-scale topology of the solar corona, but also reveal that, as recently predicted19, streamers are composed of yet smaller substreamers channelling continual density fluctuations at all visible scales.

MHC class I diversity of olive baboons (Papio anubis) unravelled by next-generation sequencing.

The olive baboon represents an important model system to study various aspects of human biology and health, including the origin and diversity of the major histocompatibility complex. After screening of a group of related animals for polymorphisms associated with a well-defined microsatellite marker, subsequent MHC class I typing of a selected population of 24 animals was performed on two distinct next-generation sequencing (NGS) platforms. A substantial number of 21 A and 80 B transcripts were discovered, about half of which had not been previously reported. Per animal, from one to four highly transcribed A alleles (majors) were observed, in addition to ones characterised by low transcripion levels (minors), such as members of the A*14 lineage. Furthermore, in one animal, up to 13 B alleles with differential transcription level profiles may be present. Based on segregation profiles, 16 Paan-AB haplotypes were defined. A haplotype encodes in general one or two major A and three to seven B transcripts, respectively. A further peculiarity is the presence of at least one copy of a B*02 lineage on nearly every haplotype, which indicates that B*02 represents a separate locus with probably a specialistic function. Haplotypes appear to be generated by recombination-like events, and the breakpoints map not only between the A and B regions but also within the B region itself. Therefore, the genetic makeup of the olive baboon MHC class I region appears to have been subject to a similar or even more complex expansion process than the one documented for macaque species.

A quick and robust MHC typing method for free-ranging and captive primate species.

Gene products of the major histocompatibility complex (MHC) of human and non-human primates play a crucial role in adaptive immunity, and most of the relevant genes not only show a high degree of variability (polymorphism) but also copy number variation (CNV) is observed. Due to this diversity, MHC proteins influence the capability of individuals to cope with various pathogens. MHC and/or MHC-linked gene products such as odorant receptor genes are thought to influence mate choice and reproductive success. Therefore, MHC typing of wild and captive primate populations is considered to be useful in conservation biology, which is, however, often hampered by the need of invasive and time-consuming methods. All intact Mhc-DRB genes in primates appear to possess a complex and highly divergent microsatellite, DRB-STR. A panel of 154 pedigreed olive baboons (Papio anubis) was examined for their DRB content by DRB-STR analysis of genomic DNA. Using the same methodology on DNA of feces samples, DRB variability of a silvery gibbon population (Hylobates moloch) (N = 24), an endangered species, could successfully be studied. In both species, length determination of the DRB-STR resulted in the definition of unique genotyping patterns that appeared to be specific for a certain chromosome. Moreover, the different STR lengths were shown to segregate with the allelic variation of the respective gene. The results obtained expand data gained previously on DRB-STR typing in macaques, great apes, and humans and strengthen the conclusion that this protocol is applicable in molecular ecology, conservation biology, and colony management, especially of endangered primate species.

[Autism spectrum disorder and evaluation of perceived stress parents and professionals: Study of the psychometric properties of a French adaptation of the Appraisal of Life Event Scale (ALES-vf)]. / Trouble du spectre de l'autisme et évaluation du stress perçu des parents et des professionnels : étude des propriétés psychométriques d'une adaptation francophone de l'Appraisal of Life Event Scale (ALES-vf).

INTRODUCTION: Autism and related disorders are grouped into the category of « Autism Spectrum Disorder ¼ (ASD) in the DSM-5. This appellation reflects the idea of a dimensional representation of autism that combines symptoms and characteristics that vary in severity and intensity. Despite common characteristics, there are varying degrees in intensity and in the onset of symptoms, ranging from a disability that can be very heavy with a total lack of communication and major disorders associated with the existence of a relative autonomy associated, sometimes, with extraordinary intellectual abilities. Parents are faced with several difficult situations, such as sleep disturbances, agitation, shouting, hetero violence, self-harm, learning difficulties, stereotyping, lack of social and emotional reciprocity, inappropriate behavior, etc. They can feel helpless and may experience stress related to these developmental and behavioral difficulties. The heterogeneity of symptoms, the presence of behavioral problems, the lack of reciprocity and autonomy also represent a challenge for practitioners in institutions and teachers at school. The objective of this research is to present the validation of a French translation of the Appraisal of Life Events Scale (ALES-vf) from Ferguson, Matthex and Cox, specifically adapted to the context of ASD. ALES was originally developed to operationalize the three dimensions of perceived stress (threat, loss and challenge) described by Lazarus and Folkman. METHODOLOGY: ALES-vf was initially translated into French and adapted to the situation of parents of children with ASD. It was subsequently administered to 343 parents, 150 paramedical professionals involved with people with ASD, and 155 teachers from an ordinary school environment and from specialized schools, welcoming in their classroom at least one child with ASD. RESULTS: An exploratory factor analysis performed on data from 170 parents highlighted two exploratory models with four and three factors, slightly different from the original three-factor model of Ferguson and his collaborators. Confirmatory analyzes were conducted on data from 173 other parents to test two exploratory models and the original model of Ferguson. It has also been tested on data from 305 professionals (paramedical professionals and teachers) and on the whole sample (parents and professionals). The results suggest a better match of the original three-factor model. In addition, Cronbach's alpha coefficients and inter-item correlations showed a good internal consistency for these three factors. Finally, variance analysis and regressions were performed to test the effect of the nationality of the parents, the child's level of autonomy, the child's level of communication, and on the perceived stress by experienced professionals. CONCLUSION: ALES-vf, after our adaptation has good psychometric properties for use not only with parents but also with professionals (teachers, educators, psychologists) working with children with ASD. Our analyses showed that the nationality of the parents does not significantly influence the subscales « threat ¼ and « challenge ¼ of ALES-vf, which makes it usable in other Francophone countries. Specificities in the subscales were identified based on group membership (parents and professionals). For example parents get higher average scores on subscales « loss ¼ and « threat ¼ and a lower average score on the subscale « challenge ¼, compared to professionals. Finally, regarding the specifics found among professionals, the results show that the years of experience have an effect on perceived stress. Specifically, teachers and educators who have more experience perceive their work with children with ASD as a challenge. This is consistent with the results of studies showing that teachers who have had experience with children with ASD had less difficulty in their interventions.

Imaging of postoperative tetralogy of Fallot repair.

Over the last years, the surgical techniques used to repair Tetralogy of Fallot as well as the cross-sectional cardiac imaging techniques have substantially improved. Now, the survival rate after surgical repair is more than 90% at 40 years old. A follow-up is needed and the imaging evaluation should be guided by the surgical techniques used. This article reviews the most common surgical procedures for a complete repair, the associated anatomic and hemodynamic complications and the role of cardiac imaging, mainly magnetic resonance imaging.

Clinical efficacy of a new CD28-targeting antagonist of T cell co-stimulation in a non-human primate model of collagen-induced arthritis.

T cells have a central pathogenic role in the aetiopathogenesis of rheumatoid arthritis (RA), and are therefore a favoured target of immunotherapy aiming at physical or functional elimination. Here we report an efficacy test of FR104, a new co-stimulation inhibitor directly targeting CD28 on T cells, in a translationally relevant model, the rhesus monkey model of collagen-induced arthritis (CIA). As a relevant comparator we used abatacept [cytotoxic T lymphocyte antigen immunoglobulin (CTLA Ig)], an antagonist of CTLA-4 binding to CD80/86 clinically approved for treatment of RA. Treatment with either compound was started at the day of CIA induction. Although FR104 previously demonstrated a higher control of T cell responses in vitro than abatacept, both compounds were equally potent in the suppression of CIA symptoms and biomarkers, such as the production of C-reactive protein (CRP) and interleukin (IL)-6 and anti-collagen type II (CII) serum antibody (IgM/IgG). However, in contrast to abatacept, FR104 showed effective suppression of CII-induced peripheral blood mononuclear cell (PBMC) proliferation. The current study demonstrates a strong potential of the new selective CD28 antagonist FR104 for treatment of RA.

Mobile-bearing versus fixed-bearing total knee implants. Results of a series of 100 randomised cases after 9 years follow-up.

HYPOTHESIS: Mobile-bearing total knee arthroplasty (TKA) implants were developed as an alternative to fixed-bearing implants because of their theoretical advantages related to wear and range of motion. For all that, none of the short-term and medium-term studies published so far have reported a significant clinical improvement related to these mobile bearings. The goal of this study was to compare the outcomes of fixed and mobile bearings in the same type of TKA model after a longer follow-up. MATERIAL AND METHODS: This series initially comprised 100 patients with a mean age of 73 years who were operated by a single surgeon. The patients were randomised to receive either a fixed bearing TKA implant or a mobile one; their outcomes evaluated after a mean of 9 years (7.2-12.2) follow-up. Twenty-two patients died before the final review, 15 were lost to follow-up and 2 were excluded. This resulted in 30 patients with a mobile-bearing knee and 31 with a fixed-bearing knee being available for analysis. RESULTS: There were no significant clinical differences between the groups receiving a fixed or mobile bearing in terms of the range of motion, subjective outcomes or validated outcomes measured, such as the self-reported Oxford or the IKS. Conversely, there was a significantly higher rate of osteolysis in the fixed-bearing group, but it was not clinically relevant. CONCLUSION: This study, which has the longest published follow-up, confirms the results found in the seven randomised studies published up to now: there are no significant differences in the clinical outcomes between fixed-bearing and mobile-bearing inserts of the same TKA model. Although the mobile bearing knees had a better radiographic appearance, this did not translate to better clinical outcomes. In practice, the superiority of mobile bearings is solely theoretical. LEVEL OF EVIDENCE II: Prospective randomised study.

Bortezomib, C1-inhibitor and plasma exchange do not prolong the survival of multi-transgenic GalT-KO pig kidney xenografts in baboons.

Galactosyl-transferase KO (GalT-KO) pigs represent a potential solution to xenograft rejection, particularly in the context of additional genetic modifications. We have performed life supporting kidney xenotransplantation into baboons utilizing GalT-KO pigs transgenic for human CD55/CD59/CD39/HT. Baboons received tacrolimus, mycophenolate mofetil, corticosteroids and recombinant human C1 inhibitor combined with cyclophosphamide or bortezomib with or without 2-3 plasma exchanges. One baboon received a control GalT-KO xenograft with the latter immunosuppression. All immunosuppressed baboons rejected the xenografts between days 9 and 15 with signs of acute humoral rejection, in contrast to untreated controls (n = 2) that lost their grafts on days 3 and 4. Immunofluorescence analyses showed deposition of IgM, C3, C5b-9 in rejected grafts, without C4d staining, indicating classical complement pathway blockade but alternate pathway activation. Moreover, rejected organs exhibited predominantly monocyte/macrophage infiltration with minimal lymphocyte representation. None of the recipients showed any signs of porcine endogenous retrovirus transmission but some showed evidence of porcine cytomegalovirus (PCMV) replication within the xenografts. Our work indicates that the addition of bortezomib and plasma exchange to the immunosuppressive regimen did not significantly prolong the survival of multi-transgenic GalT-KO renal xenografts. Non-Gal antibodies, the alternative complement pathway, innate mechanisms with monocyte activation and PCMV replication may have contributed to rejection.

FR104, an antagonist anti-CD28 monovalent fab' antibody, prevents alloimmunization and allows calcineurin inhibitor minimization in nonhuman primate renal allograft.

Selective targeting of CD28 might represent an effective immunomodulation strategy by preventing T cell costimulation, while favoring coinhibition since inhibitory signals transmitted through CTLA-4; PD-L1 and B7 would not be affected. We previously showed in vitro and in vivo that anti-CD28 antagonists suppress effector T cells while enhancing regulatory T cell (Treg) suppression and immune tolerance. Here, we evaluate FR104, a novel antagonist pegylated anti-CD28 Fab' antibody fragment, in nonhuman primate renal allotransplantation. FR104, in association with low doses of tacrolimus or with rapamycin in a steroid-free therapy, prevents acute rejection and alloantibody development and prolongs allograft survival. However, when FR104 was associated with mycophenolate mofetil and steroids, half of the recipients rejected their grafts prematurely. Finally, we observed an accumulation of Helios-negative Tregs in the blood and within the graft after FR104 therapy, confirmed by Treg-specific demethylated region DNA analysis. In conclusion, FR104 reinforces immunosuppression in calcineurin inhibitor (CNI)-low or CNI-free protocols, without the need of steroids. Accumulation of intragraft Tregs suggested the promotion of immunoregulatory mechanisms. Selective CD28 antagonists might become an alternative CNI-sparing strategy to B7 antagonists for kidney transplant recipients.

Preclinical efficacy and immunological safety of FR104, an antagonist anti-CD28 monovalent Fab' antibody.

Antagonist anti-CD28 antibodies prevent T cell costimulation and differentiate from CTLA4Ig since they cannot block CTLA-4 and PDL-1 coinhibitory signals. They demonstrated efficacy in suppressing effector T cells while enhancing regulatory T cells function and immune tolerance. However, anti-CD28 antibodies devoid of immunotoxicity and with a good pharmacokinetic profile have not yet been developed. Here, we describe FR104, a novel humanized pegylated anti-CD28 Fab' antibody fragment presenting a long elimination half-life in monkeys. In vitro, FR104 failed to induce human T cell proliferation and cytokines secretion, even in the presence of anti-CD3 antibodies or when cross-linked with secondary antibodies. Furthermore, in humanized NOD/SCID mice adoptively transferred with human PBMC, whereas superagonist and divalent antibodies elicited rapid cytokines secretion and human T cell activation, FR104 did not. These humanized mice developed a florid graft-versus-host disease, which was prevented by administration of FR104 in a CTLA4-dependent manner. Interestingly, administration of high doses of CTLA4-Ig was ineffective to prevent GVHD, whereas administration of low doses was partially effective. In conclusion, we demonstrated that FR104 is devoid of agonist activity on human T cells and thus compatible with a clinical development that might lead to higher therapeutic indexes, by sparing CTLA-4, as compared to CD80/CD86 antagonists.

CD28-specific immunomodulating antibodies: what can be learned from experimental models?

Tolerance induction to alloantigens remains a major challenge in transplant immunology. Progress in the last decade of our understanding of T-cell activation has led to the development of new immunotherapeutic strategies to replace conventional immunosuppression which inhibits the immune system in a nonspecific way. In particular, positive and negative costimulatory molecules of the CD28 family have been consistently demonstrated to be critical for the development of productive immune responses as well as the establishment and maintenance of peripheral tolerance. However, recent discoveries of novel costimulatory interactions confer a novel dimension to the immunoregulatory interactions within the B7:CD28 family and compels a revised view within a "quintet" of costimulatory molecules: CD28/B7/CTLA-4/PD-L1/ICOSL. Complexity introduced in this more detailed costimulatory pathway has important implications in therapeutic interventions against human immunological diseases and, especially, highlight the fundamental differences in selectively targeting CD28 molecules instead of B7 counterparts. In this review, we discuss these differences and emphasize different CD28-specific immunomodulating strategies evaluated in experimental models of transplantation and autoimmune diseases.

Xenotransplantation of galactosyl-transferase knockout, CD55, CD59, CD39, and fucosyl-transferase transgenic pig kidneys into baboons.

Galactosyl-transferase knockout (GT-KO) pigs represent the latest major progress to reduce immune reactions in xenotransplantation. However, their organs are still subject to rapid humoral rejection involving complement activation requiring the ongoing development of further genetic modifications in the pig. In a pig-to-baboon renal transplantation setting, we have used donor pigs that are not only GT-KO, but also transgenic for human CD55 (hCD55), hCD59, hCD39, and fucosyl-transferase (hHT). We studied kidney xenograft survival, physiological and immunologic parameters, xenogeneic rejection characteristics, as well as viral transmission aspects among two groups of baboons: control animals (n = 2), versus those (n = 4) treated with a cocktail of cyclophosphamide, tacrolimus, mycophenolate mofetil, steroids, and a recombinant human C1 inhibitor. Whereas control animals showed clear acute humoral rejection at around day 4, the treated animals showed moderately improved graft survival with rejection at around 2 weeks posttransplantation. Biopsies showed signs of acute vascular rejection (interstitial hemorrhage, glomerular thrombi, and acute tubular necrosis) as well as immunoglobulin (Ig)M and complement deposition in the glomerular and peritubular capillaries. The low level of preformed non-Gal-α1.3Gal IgM detected prior to transplantation increased at 6 days posttransplantation, whereas induced IgG appeared after day 6. No porcine endogenous retrovirus (PERV) transmission was detected in any transplanted baboon. Thus, surprisingly, organs from the GT-KO, hCD55, hCD59, hCD39, and hHT transgenic donors did not appear to convey significant protection against baboon anti-pig antibodies and complement activation, which obviously continue to be significant factors under a suboptimal immunosuppression regimen. The association, timing, and doses of immunosuppressive drugs remain critical. They will have to be optimized to achieve longer graft survivals.

Impact of preoperative maintenance or interruption of aspirin on thrombotic and bleeding events after elective non-cardiac surgery: the multicentre, randomized, blinded, placebo-controlled, STRATAGEM trial.

BACKGROUND: Patients receiving anti-platelet agents for secondary cardiovascular prevention frequently require non-cardiac surgery. A substantial proportion of these patients have their anti-platelet drug discontinued before operation; however, there is uncertainty about the impact of this practice. The aim of this study was to compare the effect of maintenance or interruption of aspirin before surgery, in terms of major thrombotic and bleeding events. METHODS: Patients treated with anti-platelet agents for secondary prevention and undergoing intermediate- or high-risk non-cardiac surgery were included in this multicentre, randomized, placebo-controlled, trial. We substituted non-aspirin anti-platelets with aspirin (75 mg daily) or placebo starting 10 days before surgery. The primary outcome was a composite score evaluating both major thrombotic and bleeding adverse events occurring within the first 30 postoperative days weighted by their severity (weights were established a priori using a Delphi consensus process). Analyses followed the intention-to-treat principle. RESULTS: We randomized 291 patients (n=145, aspirin group, and n=146, placebo group). The most frequent surgical procedures were orthopaedic surgery (52.2%), abdominal surgery (20.6%), and urologic surgery (15.5%). No significant difference was observed neither in the primary outcome score [mean values (SD)=0.67 (2.05) in the aspirin group vs 0.65 (2.04) in the placebo group, P=0.94] nor at day 30 in the number of major complications between groups. CONCLUSIONS: In these at-risk patients undergoing elective non-cardiac surgery, we did not find any difference in terms of occurrence of major thrombotic or bleeding events between preoperative maintenance or interruption of aspirin.

Antibody-mediated depletion of lymphocyte-activation gene-3 (LAG-3(+) )-activated T lymphocytes prevents delayed-type hypersensitivity in non-human primates.

Lymphocyte-activation gene-3 (LAG-3, CD223) is a marker for recently activated effector T cells. Activated T lymphocytes are of major importance in many autoimmune diseases and organ transplant rejection. Therefore, specifically depleting LAG-3(+) T cells might lead to targeted immunosuppression that would spare resting T cells while eliminating pathogenic activated T cells. We have shown previously that anti-LAG-3 antibodies sharing depleting as well as modulating activities inhibit heart allograft rejection in rats. Here, we have developed and characterized a cytotoxic LAG-3 chimeric antibody (chimeric A9H12), and evaluated its potential as a selective therapeutic depleting agent in a non-human primate model of delayed-type hypersensitivity (DTH). Chimeric A9H12 showed a high affinity to its antigen and depleted both cytomegalovirus (CMV)-activated CD4(+) and CD8(+) human T lymphocytes in vitro. In vivo, a single intravenous injection at either 1 or 0·1 mg/kg was sufficient to deplete LAG-3(+) -activated T cells in lymph nodes and to prevent the T helper type 1 (Th1)-driven skin inflammation in a tuberculin-induced DTH model in baboons. T lymphocyte and macrophage infiltration into the skin was also reduced. The in vivo effect was long-lasting, as several weeks to months were required after injection to restore a positive reaction after antigen challenge. Our data confirm that LAG-3 is a promising therapeutic target for depleting antibodies that might lead to higher therapeutic indexes compared to traditional immunosuppressive agents in autoimmune diseases and transplantation.

Recombinant human C1-inhibitor inhibits cytotoxicity induced by allo- and xenoantibodies.

Antibody-mediated rejection (AMR) is usually poorly controlled, especially in the context of pretransplant immunization, and remains an unsolved issue in xenotransplantation. In order to study prevention and/or treatment of AMR through an early blockade of the complement classical pathway, we designed two strategies to test the effect of a new recombinant human C1-inhibitor that inhibits C1 esterase (rhC1-INH; Pharming, The Netherlands), in a complement-dependent cytotoxicity assay, in the contexts of pretransplant anti-donor alloimmunization and pig-to-primate combinations in order to compare the situations. RhC1-INH appeared to be efficient, in allo- and xenotransplantation settings to block cytotoxicity when given at the initiation of (preventive strategy) or during (curative strategy) the cytotoxicity assay. Importantly, we showed that a small amount of exogenous rhC1-INH was sufficient to prevent cytotoxicity induced by anti-donor alloantibody, thus possibly helping to prevent or treat AMR in preimmunized patients. These in vitro data lead to future in vivo studies in models of AMR in pigs and baboons in allotransplantation and xenotransplantation, in which cytotoxicity due to Gal and non-Gal antibodies is so detrimental.

Pediatric heart transplantation: improving results in high-risk patients.

OBJECTIVES: Our institutional experience with 73 pediatric patients undergoing cardiac transplantation between January 1, 1990, and December 31, 1999, was reviewed to determine the impact of unconventional donor and recipient management protocols implemented to extend the availability of this therapy. METHODS AND RESULTS: The introduction of donor blood cardioplegic solution with added insulin was associated with a significant improvement in patient and graft survival (hazard ratio [Cox] = 0.25, P =.08), despite significantly longer ischemic times with this protocol compared with the use of crystalloid-based donor procurement techniques (P <.01). Eleven patients underwent intentional transplantation of ABO-incompatible donor hearts with the aid of a protocol of plasma exchange on bypass. In this subgroup, there were 2 early deaths caused by nonspecific graft failure (n = 1) and respiratory complications with mild vascular rejection (n = 1), and there was 1 late death caused by lymphoma. ABO-incompatible transplantation was not a risk factor for death by multivariate analysis. The postoperative course in these patients suggests minimal reactivity directed against incompatible grafts on the basis of low anti-donor blood group antibody production, in association with a favorable rejection profile. Ten of 13 patients requiring preoperative support with an extracorporeal membrane oxygenator survived transplantation; there were 3 additional late deaths in this subgroup (hazard ratio = 2.88, P =.05). CONCLUSIONS: The results with pediatric cardiac transplantation continue to improve as a result of changes in both surgical and medical protocols permitting successful treatment of patients conventionally considered at high risk or unsuitable for transplantation.

Modified Norwood procedure with a high-flow cardiopulmonary bypass strategy results in low mortality without late arch obstruction.

OBJECTIVE: The results of our modification of the stage I Norwood procedure, in which we use only autologous tissue to reconstruct the aortic arch, were reviewed. A high-flow, low-pressure cardiopulmonary bypass protocol (with phenoxybenzamine), before and after a period of deep hypothermic circulatory arrest, was used. METHODS: Between 1993 and 1999, 59 patients, aged 1 to 353 days (median 4 days) and weighing 1.7 to 6.8 kg (median 3.2 kg), underwent a modified Norwood procedure. The ascending aortic diameter ranged from 1.5 to 8 mm (median 3 mm). The modified Blalock-Taussig shunt was 3 mm in 21 patients (36%) and 3.5 mm or larger in 38 patients (64%). RESULTS: Deep hypothermic circulatory arrest and cardiopulmonary bypass times ranged from 15 to 64 minutes (median 37 minutes) and 44 to 144 minutes (median 88 minutes), respectively. Early postoperative survival was 83%. By univariate analysis, early mortality was associated with an ascending aortic diameter of 2.5 mm or less (P =.01). Weight, circulatory arrest and bypass times, diagnosis (hypoplastic left heart syndrome vs variant), shunt size, and date of the procedure did not affect survival. For a median follow-up period of 37 months (range 4-63 months), 42 (61%) patients underwent bidirectional cavopulmonary shunts, 10 (17%) had Fontan operations, and 1 patient underwent transplantation after a bidirectional cavopulmonary shunt. Eight patients subsequently died, for a 1-year actuarial survival of 72% (95% confidence interval: 60%-84%). Neoaortic arch obstruction was corrected in 3 patients (5%). CONCLUSIONS: At intermediate-term follow-up, our modification of the Norwood procedure together with our perioperative strategies has resulted in acceptable outcomes with a low incidence of neoaortic arch obstruction. Patients with a small ascending aortic diameter have emerged as a high-risk group, but a recent technical modification may improve the outlook for these patients.