Alloimmunisation to Donor Antigens and Immune Rejection Following Foetal Neural Grafts to the Brain in Patients with Huntington's Disease

BACKGROUND: The brain is deemed “immunologically privileged” due to sparse professional antigen-presenting cells and lymphatic drainage, and to the blood-brain barrier. Although the actual extent of this privilege is controversial, there is general consensus about the limited need in intracerebral neural grafts for immunosuppressive regimens comparable to those used in other cases of allotransplantation. This has led over the past fifteen years to the use of either short-term or even no immunosuppression in most clinical trials with foetal neural transplant in patients with Parkinson's and Huntington's disease. METHODOLOGY/PRINCIPAL FINDINGS: We report biological demonstration of alloimmunisation without signs of rejection in four grafted patients out of 13 studied during the course of a clinical trial involving fetal neural transplantation in patients with Huntington's Disease. Biological, radiological and clinical demonstration of an ongoing rejection process was observed in a fifth transplanted patient. The rejection process was, however, fully reversible under immunosuppressive treatment and graft activity recovered within six months. CONCLUSIONS/SIGNIFICANCE: There had been, up to date, no report of documented cases that could have cast a doubt on those procedures. Our results underline the need for a reconsideration of the extent of the so-called immune privilege of the brain and of the follow-up protocols of patients with intracerebral grafts. It also suggests that some of the results obtained in past studies with foetal neural transplants may have been biased by an unrecognized immune response to donor cells

Identification of genetic variants associated with Huntington's disease progression: a genome-wide association study

Background Huntington's disease is caused by a CAG repeat expansion in the huntingtin gene, HTT. Age at onset has been used as a quantitative phenotype in genetic analysis looking for Huntington's disease modifiers, but is hard to define and not always available. Therefore, we aimed to generate a novel measure of disease progression and to identify genetic markers associated with this progression measure. Methods We generated a progression score on the basis of principal component analysis of prospectively acquired longitudinal changes in motor, cognitive, and imaging measures in the 218 indivduals in the TRACK-HD cohort of Huntington's disease gene mutation carriers (data collected 2008–11). We generated a parallel progression score using data from 1773 previously genotyped participants from the European Huntington's Disease Network REGISTRY study of Huntington's disease mutation carriers (data collected 2003–13). We did a genome-wide association analyses in terms of progression for 216 TRACK-HD participants and 1773 REGISTRY participants, then a meta-analysis of these results was undertaken. Findings Longitudinal motor, cognitive, and imaging scores were correlated with each other in TRACK-HD participants, justifying use of a single, cross-domain measure of disease progression in both studies. The TRACK-HD and REGISTRY progression measures were correlated with each other (r=0·674), and with age at onset (TRACK-HD, r=0·315; REGISTRY, r=0·234). The meta-analysis of progression in TRACK-HD and REGISTRY gave a genome-wide significant signal (p=1·12 × 10−10) on chromosome 5 spanning three genes: MSH3, DHFR, and MTRNR2L2. The genes in this locus were associated with progression in TRACK-HD (MSH3 p=2·94 × 10−8 DHFR p=8·37 × 10−7 MTRNR2L2 p=2·15 × 10−9) and to a lesser extent in REGISTRY (MSH3 p=9·36 × 10−4 DHFR p=8·45 × 10−4 MTRNR2L2 p=1·20 × 10−3). The lead single nucleotide polymorphism (SNP) in TRACK-HD (rs557874766) was genome-wide significant in the meta-analysis (p=1·58 × 10−8), and encodes an aminoacid change (Pro67Ala) in MSH3. In TRACK-HD, each copy of the minor allele at this SNP was associated with a 0·4 units per year (95% CI 0·16–0·66) reduction in the rate of change of the Unified Huntington's Disease Rating Scale (UHDRS) Total Motor Score, and a reduction of 0·12 units per year (95% CI 0·06–0·18) in the rate of change of UHDRS Total Functional Capacity score. These associations remained significant after adjusting for age of onset. Interpretation The multidomain progression measure in TRACK-HD was associated with a functional variant that was genome-wide significant in our meta-analysis. The association in only 216 participants implies that the progression measure is a sensitive reflection of disease burden, that the effect size at this locus is large, or both. Knockout of Msh3 reduces somatic expansion in Huntington's disease mouse models, suggesting this mechanism as an area for future therapeutic investigation

Red blood cells free α-haemoglobin pool: a biomarker to monitor the β-thalassemia intermedia variability. The ALPHAPOOL study

International audienceThe severity of β-thalassaemia (β-thal) intermedia is mainly correlated to the degree of imbalanced α/non α-globin chain synthesis. The phenotypic diversity of β-thal depends on this imbalance and reflects all possible combinations of α- and β-globin genotypes, levels of fetal haemoglobin (HbF) and co-inheritance of other modulating factors. This study aimed to demonstrate the validity of a new surrogate of α/non α-globin biosynthetic ratio by measuring the soluble α-Hb pool in lysed red blood cells. Our results confirm that the α-Hb pool measurement allows a good discrimination between β-thal intermedia patients, controls and α-thal patients (P < 0·003). Receiver operator characteristic analyses revealed an area under the curve of 0·978 for the α-Hb pool measurement at a threshold of 120 ng free α-Hb/mg of total Hb/ml of haemolysate (ppm) with a sensitivity and specificity of 86% and 100%, respectively, to discriminate between β-thal and not β-thal subjects. Significant correlations were observed between the α-Hb pool and biological parameters of β-thal, the most significant association being observed with red cell hexokinase activity. This study indicates that the α-Hb pool could be a new marker for assistance in diagnostic orientation of β-thal intermedia patients and may be clinically useful for monitoring the evolution of the disequilibrium of globin synthesis in response to treatments

Brain imaging of the rejection process in patient 3 and its reversion under treatment.

<p>Magnetic resonance imaging and metabolic activity using ¹⁸F-deoxyglucose before surgery (T0), during the rejection process (T1) and after 6 months of reinstated immunosuppressive treatment (T2) are shown separately (upper and middle panel, respectively), then co-registered (lower panel). The white arrow indicates the right striatum. The false colour scale shows levels of metabolic activities from lowest (min) to highest (max).</p

A Wake-Up Call for Routine Morbidity and Mortality Review Meeting Procedures as Part of a Quality Governance Programs in Radiation Therapy Departments: Results of the PROUST Survey

International audiencePURPOSE:Morbidity and mortality review (MMR) meetings in radiation therapy (RT) departments aim to monitor radiation-induced toxicities and identify potential factors that may be correlated with their development and severity, particularly treatment planning errors. The aims of the Prospective Registration of Morbidity and Mortality, Individual Radiosensitivity and Radiation Technique (PROUST) survey were to make an inventory of existing MMR procedures and to describe their procedures.METHODS AND MATERIALS:The link to the web-based questionnaire of the PROUST survey was sent to 351 radiation oncologists working at 172 centers. The questionnaire included items related to organization, frequency, membership, governance, reasons for nonimplementation of MMR, and interest in its creation.RESULTS:As of July 2017, 108 responses had been received from the 172 centers, of which 107 responses were completed for analysis. All centers declared that they had initiated a quality assurance program in their department, including implementation of feedback committees dedicated to the registration, analysis, and correction of precursor events. Less than half of the centers (47%) had implemented MMR procedures. However, there was significant confusion regarding feedback committees in a majority of the centers. MMRs were organized every 6 and 12 months in 21% and 15%, respectively, of the centers. In 60% of the centers, toxicity grade ≥3 was the main reason for the MMR initiation. In routine practice, contouring and dosimetry files were reviewed by 66% and 83%, respectively, of centers practicing MMR. However, only 40% of the centers enrolled data in a registry dedicated to surveillance. Finally, 78% of centers expressed interest in initiating a consensual procedure.CONCLUSIONS:MMRs are not systematically implemented in RT departments worldwide. In France and in Europe, few departments with quality assurance programs have implemented MMRs. This survey showed that a large majority of centers are interested in implementing an MMR with a formalized procedure. Our project could help increase the interest of the RT community worldwide in this topic

Demographic and clinical characteristics of the HD patients and proxies.

<p>Data are numbers and means ± SD (<i>range</i>) unless otherwise indicated. N: numbers; UHDRS: Unified Huntington’s Disease Rating Scale [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0128209#pone.0128209.ref032" target="_blank">32</a>]; TFC: total functional capacity [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0128209#pone.0128209.ref022" target="_blank">22</a>]; MDRS: Mattis Dementia Rating Scale [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0128209#pone.0128209.ref023" target="_blank">23</a>].</p><p>Demographic and clinical characteristics of the HD patients and proxies.</p

Longitudinal analysis of information processing.

<p>Huntington’s disease patients (HD) and proxies had a similar understanding of the protocol at M0. Comprehension score decreased over time in the HD patients, whereas it remained stable in their proxies (Prox). Satisfaction with the information provided remained stable in both patients and proxies. Error bars represent standard errors.</p

COMT Val158Met Polymorphism Modulates Huntington's Disease Progression.

Little is known about the genetic factors modulating the progression of Huntington's disease (HD). Dopamine levels are affected in HD and modulate executive functions, the main cognitive disorder of HD. We investigated whether the Val158Met polymorphism of the catechol-O-methyltransferase (COMT) gene, which influences dopamine (DA) degradation, affects clinical progression in HD. We carried out a prospective longitudinal multicenter study from 1994 to 2011, on 438 HD gene carriers at different stages of the disease (34 pre-manifest; 172 stage 1; 130 stage 2; 80 stage 3; 17 stage 4; and 5 stage 5), according to Total Functional Capacity (TFC) score. We used the Unified Huntington's Disease Rating Scale to evaluate motor, cognitive, behavioral and functional decline. We genotyped participants for COMT polymorphism (107 Met-homozygous, 114 Val-homozygous and 217 heterozygous). 367 controls of similar ancestry were also genotyped. We compared clinical progression, on each domain, between groups of COMT polymorphisms, using latent-class mixed models accounting for disease duration and number of CAG (cytosine adenine guanine) repeats. We show that HD gene carriers with fewer CAG repeats and with the Val allele in COMT polymorphism displayed slower cognitive decline. The rate of cognitive decline was greater for Met/Met homozygotes, which displayed a better maintenance of cognitive capacity in earlier stages of the disease, but had a worse performance than Val allele carriers later on. COMT polymorphism did not significantly impact functional and behavioral performance. Since COMT polymorphism influences progression in HD, it could be used for stratification in future clinical trials. Moreover, DA treatments based on the specific COMT polymorphism and adapted according to disease duration could potentially slow HD progression

Reasons for consenting: motivations and expectations.

<p>Patients and proxies were asked to classify each motivation as important or not important (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0128209#pone.0128209.s001" target="_blank">S1 File</a>). ns: not significant (<i>p</i> > 0.05; Fisher’s exact test).</p><p>Reasons for consenting: motivations and expectations.</p

Structure of the latent class mixed models.

<p>Red dashed line includes variables used for the linear mixed model part. Blue dashed line includes variables used for the beta transformation. Latent domain represents the non-observable motor, behavioral, functional or cognitive domains. Observed task performances are those measured using the UHDRS. The latent motor process was modeled using the TMS; the latent behavioral process was modeled using the UHDRS behavioral score; the latent functional process was modeled using the FAS and IS scores; The latent cognitive process was modeled using letter fluency at 1 minute, letter fluency at 2 minutes, SDMT, Stroop Color, Stroop Word and Stroop Word/Color interference.</p