Littérature scientifique sur le sujet « Hu antibodies »

Purpose Hu antibodies previously have been associated with longer survival of patients with small-cell lung cancer (SCLC). Voltage-gated calcium channel (VGCC) antibodies play a pathogenic role in Lambert Eaton myasthenic syndrome, which is also associated with SCLC. These antibodies may reduce tumor growth in patients with the neurologic disease, but it is not clear whether they provide prognostic information in those without neurologic symptoms. Patients and Methods Two hundred patients with SCLC (age 39 to 79 years; mean, 62.3 years; 129 males and 71 females) receiving chemotherapy were studied for the presence of Hu and VGCC antibodies. Sera were examined for Hu antibodies by an in vitro transcription-translation–based immunoprecipitation technique and by immunohistochemistry/dot blot. VGCC (P/Q subtype) antibodies were detected by radioimmunoassay. Survival analysis was used to analyze the data. Results Hu antibodies were detected in 51 of 200 patients (25.5%) by in vitro transcription-translation–based immunoprecipitation and in 37 of 200 patients (18.5%) by immunohistochemistry or dot blot, whereas VGCC antibodies were detected in only 10 of 200 patients (5%). The presence of Hu antibodies did not correlate with VGCC antibodies, and there was no association between Hu or VGCC antibodies and the extent of disease or survival. Conclusion Hu and VGCC antibodies are found in a proportion of SCLC patients, irrespective of neurologic symptoms, but their presence does not correlate with the prognosis of the SCLC.

Background and ObjectivesTo clinically characterize post–immune checkpoint inhibitor (ICI) Hu antibody (Ab) neurologic disorders, we analyzed Hu-Ab–positive patients with neurologic immune-related adverse events (n-irAEs) and compared them with patients with other n-irAEs, ICI-naive patients with Hu-Ab paraneoplastic neurologic syndromes (PNSs) identified in the same study center, and those with Hu-Ab n-irAEs reported elsewhere.MethodsPatients whose samples were sent to the French reference center for a suspicion of n-irAE (2015–2021) were identified; those with a final diagnosis of n-irAE and Hu-Ab were included. Control groups included patients with a final diagnosis of n-irAE occurring during the same period as the patients included (2018–2021) but without Hu-Ab, and ICI-naive patients with Hu-Ab PNS diagnosed during the same period; a systematic review was performed to identify previous reports.ResultsEleven patients with Hu-Ab and n-irAEs were included (median age, 66 years, range 44–76 years; 73% men). Ten patients had small cell lung cancer, and 1 had lung adenocarcinoma. The median follow-up from onset was 3 months (range 0.5–18 months). Compared with those with other n-irAEs (n = 63), Hu-Ab–positive patients had more frequently co-occurring involvement of both central and peripheral nervous systems (36% vs 8%,p= 0.02) and limbic (54% vs 14%,p< 0.01), brainstem (27% vs 5%,p= 0.02), and dorsal root ganglia (45% vs 5%,p< 0.01) involvement. The proportion of patients with severe disability (modified Rankin Scale score >3) at diagnosis was higher among Hu-Ab n-irAEs (91% vs 52%,p= 0.02). Patients with Hu-Ab had also poorer outcome (100% vs 28%,p< 0.01) and higher mortality (91% vs 46%,p< 0.01). There was no significant difference in terms of clinical features between Hu-Ab n-irAEs and ICI-naive Hu-Ab PNS (n = 92), but there was a poorer outcome (56/78, 71%,p< 0.01) and higher mortality (26%,p< 0.01) among the former. No significant difference was found between the patients reported herein and those in the literature.DiscussionThe presence of Hu-Ab identifies a subgroup of n-irAEs that consistently reproduce the phenotypes of Hu-Ab-related PNS, supporting the hypothesis of ICI triggering or unmasking PNS. As these patients show high disability and mortality, further studies are required to investigate the underlying immunopathogenic mechanisms and to improve the outcome of Hu-Ab n-irAEs.

Background: While anti-Hu antibody associated encephalitis has been well-documented in association with a variety of neoplastic processes, paraneoplastic limbic encephalitis and sensory ganglionopathy with positive anti-Hu antibodies has not previously been linked in the literature with a neuroendocrine gastric tumour of advanced stage. Methods: Case report Results: We present the case of an 86-year old woman who developed behavioural changes, paroxysmal anxiety attacks and poor balance several months after being diagnosed with poorly differentiated gastric small cell tumour in a clinical setting of weight loss and anemia. Anti-Hu antibodies were present. MRI showed signal abnormalities in the right mesial temporal lobe with contrast enhancement. Paroxysmal lateralized EEG changes were recorded and EMG/NCS showed absent sensory nerve responses. Behavioural symptoms stabilized under treatment with intravenous immunoglobulins, but sensory ataxia continued to worsen. The patient declined further therapy and deceased two months after transfer to palliative care. Conclusions: To our knowledge, this is the first report linking small cell gastric tumour with limbic encephalitis, sensory ganglionopathy-associated ataxia and anti-Hu antibodies. This description further broadens the clinical spectrum of anti-Hu syndrome.

Abstract Severe combined immunodeficient (SCID) mice engrafted with human peripheral blood leukocytes (hu-PBL-SCID) represent a potentially important small animal model for the study of human immune function. Attempts to generate human primary immune responses to exogenous Ag in the hu-PBL-SCID have had limited success which raises questions about the functional capacity of human lymphocytes in the SCID environment. Here, we demonstrate that the spontaneously secreted human Ig in hu-PBL-SCID includes antibodies with specificity for several different mouse RBC (mRBC) proteins. These antibodies apparently reflect the transfer of peripheral B cells which are responsible for the production of naturally occurring xenoreactive antibodies in the donor. Western blot analysis showed that engraftment of anti-mRBC specificities was random among mice receiving PBL from the same donor sample. In at least one mouse, this engraftment was polyclonal and included human IgM and IgG which recognized at least 12 different mRBC proteins ranging in size from 35 to &gt; 200 kDa. Anti-mRBC specificities were found to vary with time demonstrating a dynamic expression of the human xenoreactive repertoire in hu-PBL-SCID. In contrast to mice engrafted with human PBL, mice engrafted with another source of human B cells, i.e., tumor-infiltrating leukocytes, produced very little or no human anti-mRBC antibody. Ag-driven proliferation of xenoreactive clones may result in a skewing of the engrafted human B cells in hu-PBL-SCID which could account in part for the limited ability of hu-PBL-SCID to respond to exogenous Ag. The long term production of anti-mRBC antibodies and the modulation of the expressed xenoreactive repertoire observed in hu-PBL-SCID represents an opportunity to study the molecular genetics and cell biology of the human humoral immune response to a defined complex Ag.

ABSTRACT Hemolytic-uremic syndrome (HUS) is a serious complication which is predominantly associated in children with infection by Shiga toxin-producing Escherichia coli (STEC). By using HuMAb-Mouse (Medarex) animals, human monoclonal antibodies (Hu-MAbs) were developed against Shiga toxin 1 (Stx1) for passive immunotherapy of HUS. Ten stable hybridomas comprised of fully human heavy- and light-chain immunoglobulin elements and secreting Stx1-specific Hu-MAbs (seven immunoglobulin M(κ) [IgM(κ)] elements [one specific for the A subunit and six specific for the B subunit] and three IgG1(κ) elements specific for subunit B) were isolated. Two IgM(κ) Hu-MAbs (2D9 and 15G9) and three IgG1(κ) Hu-MAbs (5A4, 10F4, and 15G2), all specific for subunit B, demonstrated marked neutralization of Stx1 in vitro and significant prolongation of survival in a murine model of Stx1 toxicosis.

Les syndromes neurologiques paranéoplasiques (SNP) associés aux anticorps Hu sont, généralement, associés à des cancers du poumon à petites cellules (CPPC). Le spectre clinique des Hu-SNP est très hétérogène, et la base immunologique de cette hétérogénéité n’est pas connue. De plus, seule une minorité de patients CPPC développent des Hu-SNP, la raison en est également inconnue. Ce projet de thèse vise à phénotyper les patients Hu-SNP et à explorer leurs caractéristiques biologiques, ainsi que les spécificités génomiques et transcriptomiques de leurs CPPC. Dans un premier temps, une classification hiérarchique a identifié trois groupes chez 466 individus Hu-SNP: atteinte du système nerveux central (SNC), neuropathie isolée et phénotypes mixtes SNC/périphériques. La survie était similaire dans les trois groupes, principalement déterminée par l’évolution du cancer, mais la dysautonomie influençait la mortalité neurologique. Les atteintes du tronc cérébral entraînaient une dysautonomie cardiovasculaire fatale ou une hypoventilation centrale, tandis que l'atteinte neurologique périphérique entraînait des troubles gastro-intestinaux ou sécrétoires, sans risque accru de mortalité. Nous avons aussi étudié des patients ayant développé des Hu-SNP après un traitement par inhibiteurs de checkpoint immunitaire (ICI). Ces patients, cliniquement indistinguables des cas spontanés, suggéraient que les ICI pourraient induire des Hu-SNP. Dans une deuxième partie, le génotypage de 100 patients a confirmé une association avec l'haplotype DR3~DQ2, essentiellement chez les patients avec neuropathie sensitive et absent chez les patients ayant une atteinte exclusive du SNC. Le séquençage par immunoprécipitation de phages a évalué la réactivité des épitopes des anticorps Hu ainsi que d'autres autoanticorps dans le sérum et/ou LCR de 210 patients. Aucune association n'a été trouvée avec l'épitote dominant Hu, mais la réactivité des épitopes différait entre le sérum et le LCR chez 75 % des échantillons appariés. Cette variation était liée au moment du prélèvement et au phénotype: les patients avec des épitopes divergents avaient des LCR prélevés plus tard, tandis que ceux avec des épitopes similaires avaient toujours une atteinte du SNC. Nous avons aussi identifié des réactivités contre d'autres protéines, certaines dans le sérum et/ou LCR, et certaines étaient corrélées à des phénotypes cliniques spécifiques. Enfin, nous avons examiné les caractéristiques moléculaires du CPPC de patients Hu-, GABAbR-SNP et témoins. Nous n’avons trouvé aucune mutation, gain, délétion ou surexpression dans les gènes Hu des patients Hu-SNP. Cependant, un profil transcriptomique distinct, avec des gènes surexprimés liés aux processus immunitaires, caractérisait les tumeurs des Hu-SNP. Nous avons aussi identifié des gènes spécifiquement surexprimés dans le CPPC des patients avec neuropathie sensitive, certains liés à l'axonogenèse et au développement de la neuropathie. Nos résultats suggèrent que plusieurs facteurs contribuent à la variabilité clinique des Hu-SNP, notamment un large spectre d'autoantigènes. Ceux-ci peuvent être liés aux profils d'expression génique dans le CPPC, certains gènes associés à l'axonogenèse étant surexprimés chez les patients ayant une neuropathie sensitive. Une prédisposition génétique pourrait également favoriser certains phénotypes, comme l'indique l'association DR3~DQ2 avec la neuropathie sensitive. La compartimentation au sein du système nerveux pourrait également contribuer: la plupart des patients ciblaient différents épitopes Hu dans leur sérum et dans leur LCR, avec certains autoantigènes plus spécifiques au LCR. Enfin, les altérations des gènes Hu dans le CPPC ne semblent pas participer à la rupture de tolérance immune, mais un profil transcriptomique distinct et les ICI pourraient y contribuer. Ce travail fait progresser la compréhension des Hu-SNP et ouvre la voie de futures recherches sur les mécanismes de l'immunité paranéoplasique
Hu antibodies, the most common in paraneoplastic neurological syndromes (PNS), strongly indicate small-cell lung cancer (SCLC). The clinical spectrum of Hu-PNS is diverse, most patients develop multifocal central, peripheral, and/or autonomic nervous system dysfunction. Despite extensive research, questions remain, namely regarding the immunological basis of clinical heterogeneity and why only a minority of SCLC patients develop Hu-PNS. Our PhD project aims to phenotype Hu-PNS patients, explore the immunogenetics and humoral responses underlying neurological phenotypes, and the genomic and transcriptomic features of their SCLC. First, we described 466 Hu-PNS patients. Hierarchical clustering identified three groups: patients with central nervous system (CNS) involvement; isolated neuropathy; and mixed CNS/peripheral phenotypes. Overall survival was similar across groups, primarily determined by cancer, but dysautonomia, present in 26% of patients, significantly influenced neurological mortality. Prominent CNS dysfunction led to fatal cardiovascular dysautonomia or central hypoventilation, while peripheral involvement was associated with gastrointestinal or secretomotor alterations, without increased mortality risk. We also characterized patients who developed neurological syndromes with Hu antibodies after immune checkpoint inhibitor (ICI) treatment. These patients were clinically indistinguishable from spontaneous cases and shared a strong association with SCLC, suggesting ICIs may induce Hu-PNS. Second, we immunologically investigated neurological phenotypes using two approaches. HLA genotyping of 100 patients confirmed an association with the DR3~DQ2 haplotype, particularly in patients with sensory neuropathy, and absent in those with only CNS involvement. Phage immunoprecipitation sequencing was used to evaluate Hu antibody epitope reactivity and other autoantibodies in serum and/or CSF of 210 patients. We found no direct clinical association with the Hu dominant epitope, but epitope reactivity differed between serum and CSF in 75% of patients with paired samples. This variation correlated with sample timing and phenotype: CSF from patients with differing serum/CSF epitopes was collected later after PNS onset, while patients with serum/CSF consistent epitope reactivity always had CNS phenotypes. In addition, we identified reactivities to other proteins, some more specific to serum or CSF, and a subset linked to specific phenotypes. Third, we examined SCLC molecular features of Hu-, GABAbR-PNS and control patients. Next-generation sequencing, copy number variation analysis, and bulk-RNA sequencing revealed no mutations, gains, deletions, or overexpression in the Hu gene family of Hu-PNS SCLC. However, a distinct transcriptomic profile with upregulated genes largely related to immune system processes characterized these tumors. We also identified specific genes upregulated in the SCLC of patients with sensory neuropathy, some of which were linked to axonogenesis and neuropathy development. Our findings suggest multiple factors contribute to Hu-PNS clinical variability, particularly a broad range of additional autoantigens. These may be partly driven by gene expression patterns in SCLC, as some upregulated genes in patients with sensory neuropathy were linked to axonogenesis. Genetic predisposition may also favor specific phenotypes, as the DR3~DQ2 haplotype was associated with sensory neuropathy. Compartmentalization within the nervous system could further contribute, as most patients targeted different Hu epitopes in serum and CSF, and some autoantigens were more specific to CSF. Finally, Hu genes alterations in SCLC are unlikely causes of neoantigenicity, while a distinct immune-related gene profile and ICIs could contribute to immune tolerance breakdown. This work advances understanding of Hu-PNS complexity and paves the way for further studies into the immunological and molecular drivers of paraneoplastic immunity

Autoimmune encephalitis clinically encapsulates a spectrum of disorders including limbic encephalitis, and other autoimmune CNS disorders, which often have a paraneoplastic cause. Unlike multiple sclerosis, autoimmune encephalitides are unified by well-characterized neural-specific IgG biomarkers detectable in serum or CSF. Diagnostic laboratory, in vitro and neuropathological studies have demonstrated two broad groups. The first, characterizable by the detection of neuronal nuclear, cytoplasmic, or nucleolar antibodies (such as ANNA-1, aka anti-Hu), likely have a cytotoxic T cell mediated pathogenesis. The second, characterizable by the detection of antibodies targeting plasma membrane antigens, such as NMDA receptor, are likely mediated (at least in part) by pathogenic antibody.

Certain tumour types can cause psychopathology through direct biological mechanisms such as metastatic spread to the brain, release of onconeuronal antibodies, ectopic hormone secretion, or release of pro-inflammatory cytokines. Lung cancers, adenocarcinoma of the pancreas, brain tumours, and ovarian tumours are considered in detail. Confusional states due to brain metastases, syndrome of inappropriate ADH secretion, hypercalcaemia of malignancy, and anti-Hu encephalitis are found in lung cancers. Severe depression, due to interleukin-6 release and its actions on the HPA axis and tryptophan metabolism, is common in adenocarcinoma of the pancreas. Anti-NMDA-receptor limbic encephalitis, clinically indistinguishable from acute schizophrenia, can complicate teratomas. Gliomas, pituitary tumours, and thyroid, adrenal, and testicular tumours can also disrupt mental health through various biological mechanisms described here.

Paraneoplastic myelopathies are uncommon, but maintenance of a high index of clinical suspicion is critical, as the neurological syndrome often predates discovery of an underlying malignancy and can facilitate early detection and potentially improve prognosis. Most paraneoplastic myelopathies are associated with additional neurological symptomatology, such as encephalitis, peripheral neuropathy, or cerebellar ataxia, due to the specific, respective auto-antibodies involved. Anti-Hu antibody, identified in our patient, appears to be the most common antibody, followed by amphiphysin, and collapsing response mediator protein 5, among others. The therapeutic approach to patients with paraneoplastic myelopathies focuses primarily on treatment of the underlying cancer and, thereafter, subsequent trials of immunotherapies, which have demonstrated variable response.

When colloidal droplets evaporate, material is often deposited at the periphery in a coffee-ring pattern. An understanding of colloidal transport and deposition in evaporating droplets is critical for optimization of many medical diagnostic devices and printing processes. This phenomenon can also be used for nanoparticle self-assembly, containerless materials processing, and manufacturing of flexible electronics. The forces affecting colloidal transport can be categorized as (i) convective effects, (ii) particle diffusion, and (iii) boundary effects. Knowledge of fluid flow in an evaporating droplet is required to understand particle transport when convection effects dominate over particle diffusion. The evaporative radial flow identified by Deegan et al. [1] is the result of contact line pinning and high evaporation flux at the contact line. Hu and Larson later identified that dominance of thermal Marangoni recirculation within the droplet can suppress ring formations by convecting particles to the center of the deposition. Bhardwaj et al. [2] demonstrated that van der Walls and electrostatic forces can dominate colloidal transport and capture particles on the substrate to form uniform depositions. These effects are represented by the Derjaguin, Verwey, and Overbeek (DLVO) force. This force can attract or repel particles from the surface or other particles when they are separated by less than the Debye length. Attractive DLVO forces result in uniform depositions when they dominate over the evaporative and Marangoni flows in evaporating droplets. Particle capture on the substrate has also been achieved by antibodies-antigen reactions, or by leveraging magnetic and electrophoretic forces. Particles can also be captured on the interface of evaporating droplets. Li et al. [3] observed uniform colloidal monolayers when water droplets were evaporated at elevated temperatures. They argued that particles were being captured on the interface in these cases as the particle diffusion rate was smaller than the velocity of the collapsing interface. This work will find a low cost method for electrowetting assisted deposition and examine how electric fields can disrupt the interplay between convection, diffusion, and interface trapping in evaporating colloidal droplets. Application of AC and DC electric fields has the potential to suppress the coffee-ring effect by independently controlling the shape of the fluid interface, the contact angle hysteresis, and the motion of particles suspended in the droplet. This investigation will compare the interfacial evolution and deposition patterns left by evaporating protein laden droplets under AC and DC fields to examine their suitability for medical diagnostic applications.