Unrecognized volatile and semi-volatile organic compounds from brake wear

Motor vehicles are among the major sources of pollutants and greenhouse gases in urban areas and a transition to "zero emission vehicles" is underway worldwide. However, emissions associated with brake and tire wear will remain. We show here that previously unrecognized volatile and semi-volatile organic compounds, which have a similarity to biomass burning emissions are emitted during braking. These include greenhouse gases or, these classified as Hazardous Air Pollutants, as well as nitrogen-containing organics, nitrogen oxides and ammonia. The distribution and reactivity of these gaseous emissions are such that they can react in air to form ozone and other secondary pollutants with adverse health and climate consequences. Some of the compounds may prove to be unique markers of brake emissions. At higher temperatures, nucleation and growth of nanoparticles is also observed. Regions with high traffic, which are often disadvantaged communities, as well as commuters can be impacted by these emissions even after combustion-powered vehicles are phased out.

The Histopathology of Cold Agglutinin Disease-Associated B-Cell Lymphoproliferative Disease

OBJECTIVES

Primary cold agglutinin disease is a type of autoimmune hemolytic anemia caused by circulating antibodies against I antigen, a carbohydrate expressed on most cells, including red blood cells. The underlying disease has been characterized in recent years as a distinct B-cell lymphoproliferative disease of the bone marrow, occurring mostly in the elderly. The disease has been now been included as a separate entity in the most recent classifications of mature B-cell neoplasms.

METHODS

A review of the characteristics of cold agglutinin disease is provided, with an emphasis on the pathology features.

RESULTS

A detailed description of the histopathology, immunophenotype, and genetics of cold agglutinin disease is provided and compared to other B-cell lymphoproliferative diseases in the bone marrow with similar features.

CONCLUSIONS

Recognition of the pathology features of cold agglutinin disease allows to distinguish it from other diseases, especially lymphoplasmacytic lymphoma and marginal zone lymphoma.

Deep Learning Accurately Quantifies Plasma Cell Percentages on CD138-Stained Bone Marrow Samples

The diagnosis of plasma cell neoplasms requires accurate, and ideally precise, percentages. This plasma cell percentage is often determined by visual estimation of CD138-stained bone marrow biopsies and clot sections. While not necessarily inaccurate, estimates are by definition imprecise. For this study, we hypothesized that deep learning can be used to improve precision. We trained a semantic segmentation-based convolutional neural network (CNN) using annotations of CD138+ and CD138- cells provided by one pathologist on small image patches of bone marrow and validated the CNN on an independent test set of image patches using annotations from two pathologists and a non-deep learning commercial software. On validation, we found that the intraclass correlation coefficients for plasma cell percentages between the CNN and pathologist #1, a non-deep learning commercial software and pathologist #1, and pathologists #1 and #2 were 0.975, 0.892, and 0.994, respectively. The overall results show that CNN labels were almost as accurate as pathologist labels at a cell-by-cell level. Once satisfied with performance, we scaled-up the CNN to evaluate whole slide images (WSIs), and deployed the system as a workflow friendly web application to measure plasma cell percentages using snapshots taken from microscope cameras.

The impact of establishing a regional infective endocarditis (IE) network on pre-operative IE-related complications and on post-operative outcome

Background

Infective endocarditis (IE) requires a high degree of suspicion and advanced level of multidisciplinary management. In 2015, the European guidelines recommended the formation of an endocarditis-team (ET) for optimal treatment of IE. In 2011, we already established an ET within the hospital that was only consulted on demand for certain patients. Since 2015, ET has been increasingly involved in the management of almost all patients with IE. In addition, we established in 2015 a statewide endocarditis- (E) network for the referring hospitals.

Purpose

We investigated the effect of E-network on reducing referral latency and pre-operative IE-related complications. We also investigated the adherence to the ET management recommendations in our hospital and its impact on post-operative stroke and mortality.

Methods

We retrospectively analyzed data from patients operated for IE in our center between 01/2007 and 03/2018. We conducted univariate analysis using Chi-square or Fisher's exact test, Multivariate logistic regression models for in-hospital mortality and post-operative stroke, and Kaplan-Meier estimate of 5-years survival.

Results

Among 630 patients operated for IE in our center, 409 (65%) underwent surgery in the 1st era before 12/2014. S. aureus IE was more frequent in the second era (34% vs 25%, p<0.001). The median time from the onset of symptoms to referral in the 2nd era was halved compared to the first one [7 days (IQR 2–19) vs 15 days (IQR 6–35)]. Patients in the 2nd era were admitted with less IE-related complications, i.e. less preoperative stroke (14% vs 27%, p<0.001), less heart failure (45% vs 69%, p<0.001) less cardiac abscesses (24% vs 34%, p=0.018), less acute renal insufficiency requiring hemodialysis (8% vs 14%, p=0.026). The lack of ET management recommendations was an independent predictor for in-hospital mortality (adjusted OR: 2.13, 95% CI: 1.27–3.53, p=0.004) and post-operative stroke (adjusted OR: 2.23, 95% CI: 1.12–4.39, p=0.02), and was associated with worse 5-years survival (59% compared to 40%, log rank<0.001).

Conclusion

Endocarditis-network led to earlier referral of patients, which resulted in less IE-related complications on admission. Lack of ET management recommendations was an independent predictor for post-operative stroke, in-hospital mortality and was associated with worse 5-years survival.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Cropland trees need to be included for accurate model simulations of land-atmosphere heat fluxes, temperature, boundary layer height, and ozone

Trees significantly impact land-atmosphere feedbacks through evapotranspiration, photosynthesis and isoprene emissions. These processes influence the local microclimate, air quality and can mitigate temperature extremes and sequester carbon dioxide. Despite such importance, currently only 5 out of 15 atmospheric chemistry climate models even partially account for the presence of cropland trees. We first show that the tree cover over intensely farmed regions in Asia, Australia and South America is significantly underestimated (e.g. only 1-3% tree cover over north-India) in the Model of Emissions of Gases and Aerosol from Nature (MEGAN) and absent in Noah land-surface module of the Weather Research and Forecasting (WRF-Chem) Model. By including the actual tree cover (~10%) over the north-west Indo Gangetic Plain in the Noah land-surface module of the WRF-Chem and the MEGAN module, during the rice growing monsoon season in August, we find that the latent heat flux alone increases by 100%-300% while sensible heat flux reduces by 50%-100%, leading to a reduction in daytime boundary layer height by 200-400 m. This greatly improves agreement between the modelled and measured temperature, boundary layer height and surface ozone, which were earlier overestimated and isoprene and its oxidation products which were earlier underestimated. Mitigating peak daytime temperatures and ozone improves rice production by 10 to 20%. Our findings from north west Indo-Gangetic Plain establish that such plantations mitigate heat stress, and have beneficial effects on crop yields while also sequestering carbon. Expanding agroforestry practices to 50% of the cropland area could result in up to 40% yield gain regionally. Implementing such strategies globally could increase crop production and sequester 0.3-30 GtC per year, and therefore future climate mitigation and food security efforts should consider stakeholder participation for increased cropland agroforestry in view of its beneficial effects.

Cortisol during adolescence organises personality traits and behavioural syndromes

Despite the growing evidence for the importance of developmental experiences shaping consistent individual differences in behaviour and physiology, the role of endocrine factors underlying the development and maintenance of such differences across multiple traits, remains poorly understood. Here, we investigated how an experimental manipulation of circulating glucocorticoids during early adolescence affects behavioural and physiological variation and covariation later in life in the precocial cavy (Cavia aperea). Plasma cortisol concentrations were experimentally elevated by administering cortisol via food for 3 weeks. Struggle docility, escape latency, boldness, exploration and social behaviour were then tested three times after individuals attained sexual maturity. In addition, blood samples were taken repeatedly to monitor circulating cortisol concentrations. Exogenous cortisol affected mean trait expression of plasma cortisol levels, struggle docility and escape latency. Repeatability of cortisol and escape latency was increased and repeatability of struggle docility tended to be higher (approaching significance) in treated individuals. Increased repeatability was mainly caused by an increase of among-individual variance. Correlations among docility, escape latency and cortisol were stronger in treated animals compared to control animals. These results suggest that exposure to elevated levels of cortisol during adolescence can alter animal personality traits as well as behavioural syndromes. Social and risk-taking traits showed no correlation with cortisol levels and were unaffected by the experimental manipulation, indicating behavioural modularity. Taken together, our data highlight that cortisol can have organising effects during adolescence on the development of personality traits and behavioural syndromes, adding to the increasing evidence that not only early life but also adolescence is an important sensitive period for behavioural development.

First-in-man study with a novel PEGylated recombinant human insulin-like growth factor-I

OBJECTIVE

This study is a first time assessment of safety and tolerability, pharmacokinetics, and pharmacodynamics of RO5046013 in human, in comparison with unmodified rhIGF-I.

DESIGN

The study was conducted as a single-center, randomized, double-blinded, placebo-controlled, single ascending dose, parallel group study in a clinical research unit in France. A total of 62 healthy volunteers participated in this clinical trial. RO5046013 was given as single subcutaneous injection, or as intravenous infusion over 48h, at ascending dose levels. The active comparator rhIGF-I was administered at 50μg/kg subcutaneously twice daily for 4days. Safety and tolerability, pharmacokinetics, and pharmacodynamics of RO5046013 were evaluated.

RESULTS

PEGylation resulted in long exposure to RO5046013 with a half-life of 140-200h. Exposure to RO5046013 increased approximately dose proportionally. RO5046013 was safe and well tolerated at all doses, injection site erythema after SC administration was the most frequent observed AE. No hypoglycemia occurred. Growth hormone (GH) secretion was almost completely suppressed with rhIGF-I administration, whereas RO5046013 caused only a modest decrease in GH at the highest dose given IV.

CONCLUSIONS

PEGylation of IGF-I strongly enhances half-life, reduces the negative GH feedback and hypoglycemia potential, and therefore offers a valuable alternative to rhIGF-I in treatment of relevant diseases.

Perceived cognitive impairments after critical illness: a longitudinal study in survivors and family member controls

BACKGROUND

Many former intensive care unit (ICU) patients report difficulties in cognitive functions especially in their daily life. We aimed to measure perceived cognitive impairments in daily life in survivors of critical illness and their family member controls (FMC).

METHODS

Perceived cognitive impairments were assessed two times after ICU discharge using an adapted German version of the "Functional Assessment of Cancer Therapy - Cognitive Function" questionnaire. After 3 months, 127 former patients and 52 FMC participated and 103/127 patients and 36/52 FMC were followed up after 6 months. Baseline information was obtained retrospectively.

RESULTS

We found no significant differences between the patient sample and FMC, 3 and 6 months after ICU discharge. Based on questionnaire ratings, cluster analysis divided patients and FMC into a cognitively 'impaired' and a 'non-impaired' cluster. Questionnaire scales differed significantly prior to ICU admission as well as 3 and 6 months after ICU discharge between both clusters. While differences between patients and FMC were less pronounced in the 'non-impaired' cluster, patients were significantly more impaired than FMC at 3 and 6 months after ICU discharge in the 'impaired' cluster.

DISCUSSION

A substantial part of former patients were affected by post-ICU cognitive impairment in daily life. Pre-existing cognitive impairments were a risk factor. These patients would probably profit from tailored neurorehabilitative therapy. Therefore, an efficient tool to identify potential patients for neurorehabilitation is needed. The questionnaire revealed good psychometric properties. We recommend a comprehensive validation of the questionnaire in this patient population.

Similar local, but different systemic, metabolomic responses of closely related pine subspecies to folivory by caterpillars of the processionary moth

Plants respond locally and systemically to herbivore attack. Most of the research conducted on plant-herbivore relationships at element and molecular levels have focused on the elemental composition or/and certain molecular compounds or specific families of defence metabolites showing that herbivores tend to select plant individuals or species with higher nutrient concentrations and avoid those with higher levels of defence compounds. We performed stoichiometric and metabolomics, both local and systemic, analyses in two subspecies of Pinus sylvestris under attack from caterpillars of the pine processionary moth, an important pest in the Mediterranean Basin. Both pine subspecies responded locally to folivory mainly by increasing relative concentrations of terpenes and some phenolics. Systemic responses differed between pine subspecies, and most of the metabolites presented intermediate concentrations between those of the affected parts and unattacked trees. Our results support the hypothesis that foliar nutrient concentrations are not a key factor for plant selection by adult female processionary moths for oviposition, since folivory was not associated with any of the elements analysed. Phenolic compounds generally did not increase in the attacked trees, questioning the suggestion of induction of phenolics following folivory attack and the anti-feeding properties of phenolics. Herbivory attack produced a general systemic shift in pines, in both primary and secondary metabolism, which was less intense and chemically different from the local responses. Local pine responses were similar between pine subspecies, while systemic responses were more distant.

Dysautonomia in prodromal α-synucleinopathy: peripheral versus central autonomic degeneration

BACKGROUND AND PURPOSE

There is an urgent need for early predictive markers for the course of disease in prodromal α-synucleinopathies such as idiopathic rapid eye movement (REM) sleep behaviour disorder. Autonomic cardiac/vascular dysfunction is a prominent feature in advanced α-synucleinopathies, but its diagnostic value as an early neurodegenerative marker remains unclear. The latter may be complicated since synuclein-mediated neurodegeneration may involve central and peripheral components of the autonomic nervous system.

METHODS

The diagnostic value of autonomic symptoms and central and peripheral autonomic markers of blood pressure and heart rate regulation were prospectively evaluated in 20 subjects with idiopathic REM sleep behaviour disorder and 20 age-matched healthy controls.

RESULTS

Although subjects with REM sleep behaviour disorder showed no clinical autonomic symptoms, blood pressure (P ≤ 0.035) and heart rate response (P ≤ 0.065) were slightly diminished during orthostatic challenge. Autonomic dysregulation was distinctively reflected in lower resting heart rate (all components, P ≤ 0.05) and blood pressure variability (low frequency component, P ≤ 0.024) indicating peripheral cardiac/vascular denervation. In contrast, baroreflex sensitivity and central cardiac autonomic outflow (sympathovagal balance) were well preserved indicating intact central autonomic regulation. Heart rate variability [very low frequency component, receiver operating characteristic (ROC) area under the curve (AUC) 0.80, P ≤ 0.001] and blood pressure variability (low frequency component ROC AUC 0.73, P ≤ 0.01) but not baroreflex sensitivity and sympathovagal balance showed an excellent diagnostic accuracy in identifying subjects with REM sleep behaviour disorder and healthy controls.

CONCLUSIONS

Cardiac/vascular dysfunction in prodromal α-synucleinopathy arises from peripheral rather than from central autonomic degeneration. Autonomic indices encoded in heart rate and blood pressure variability are precise functional markers of early synuclein-mediated neurodegeneration.

Within-litter differences in personality and physiology relate to size differences among siblings in cavies

Many aspects of an animal's early life potentially contribute to long-term individual differences in physiology and behaviour. From several studies on birds and mammals it is known that the early family environment is one of the most prominent factors influencing early development. Most of these studies were conducted on highly altricial species. Here we asked whether in the highly precocial cavy (Cavia aperea) the size rank within a litter, i.e. whether an individual is born as the heaviest, the lightest or an intermediate sibling, affects personality traits directly after birth and after independence. Furthermore, we investigated whether individual states (early growth, baseline cortisol and resting metabolic rate) differ between siblings of different size ranks and assessed their relation to personality traits. Siblings of the same litter differed in personality traits as early as three days after birth. Pups born heaviest in the litter were more explorative and in general more risk-prone than their smaller siblings. Physiological state variables were tightly correlated with personality traits and also influenced by the size rank within litter, suggesting that the size relative to littermates constitutes an important factor in shaping an individual's developmental trajectory. Our data add valuable information on how personalities are shaped during early phases of life and indicate the stability of developmentally influenced behavioural and physiological traits.

An ecosystem-scale perspective of the net land methanol flux: synthesis of micrometeorological flux measurements

Methanol is the second most abundant volatile organic compound in the troposphere and plays a significant role in atmospheric chemistry. While there is consensus about the dominant role of living plants as the major source and the reaction with OH as the major sink of methanol, global methanol budgets diverge considerably in terms of source/sink estimates reflecting uncertainties in the approaches used to model, and the empirical data used to separately constrain these terms. Here we compiled micrometeorological methanol flux data from eight different study sites and reviewed the corresponding literature in order to provide a first cross-site synthesis of the terrestrial ecosystem-scale methanol exchange and present an independent data-driven view of the land-atmosphere methanol exchange. Our study shows that the controls of plant growth on the production, and thus the methanol emission magnitude, and stomatal conductance on the hourly methanol emission variability, established at the leaf level, hold across sites at the ecosystem-level. Unequivocal evidence for bi-directional methanol exchange at the ecosystem scale is presented. Deposition, which at some sites even exceeds methanol emissions, represents an emerging feature of ecosystem-scale measurements and is likely related to environmental factors favouring the formation of surface wetness. Methanol may adsorb to or dissolve in this surface water and eventually be chemically or biologically removed from it. Management activities in agriculture and forestry are shown to increase local methanol emission by orders of magnitude; they are however neglected at present in global budgets. While contemporary net land methanol budgets are overall consistent with the grand mean of the micrometeorological methanol flux measurements, we caution that the present approach of simulating methanol emission and deposition separately is prone to opposing systematic errors and does not allow taking full advantage of the rich information content of micrometeorological flux measurements.

An ecosystem-scale perspective of the net land methanol flux: synthesis of micrometeorological flux measurements

Methanol is the second most abundant volatile organic compound in the troposphere and plays a significant role in atmospheric chemistry. While there is consensus about the dominant role of living plants as the major source and the reaction with OH as the major sink of methanol, global methanol budgets diverge considerably in terms of source/sink estimates reflecting uncertainties in the approaches used to model, and the empirical data used to separately constrain these terms. Here we compiled micrometeorological methanol flux data from eight different study sites and reviewed the corresponding literature in order to provide a first cross-site synthesis of the terrestrial ecosystem-scale methanol exchange and present an independent data-driven view of the land-atmosphere methanol exchange. Our study shows that the controls of plant growth on the production, and thus the methanol emission magnitude, and stomatal conductance on the hourly methanol emission variability, established at the leaf level, hold across sites at the ecosystem-level. Unequivocal evidence for bi-directional methanol exchange at the ecosystem scale is presented. Deposition, which at some sites even exceeds methanol emissions, represents an emerging feature of ecosystem-scale measurements and is likely related to environmental factors favouring the formation of surface wetness. Methanol may adsorb to or dissolve in this surface water and eventually be chemically or biologically removed from it. Management activities in agriculture and forestry are shown to increase local methanol emission by orders of magnitude; they are however neglected at present in global budgets. While contemporary net land methanol budgets are overall consistent with the grand mean of the micrometeorological methanol flux measurements, we caution that the present approach of simulating methanol emission and deposition separately is prone to opposing systematic errors and does not allow taking full advantage of the rich information content of micrometeorological flux measurements.

Characterization of fetal growth by repeated ultrasound measurements in the wild guinea pig (Cavia aperea)

Fetal growth during pregnancy has previously been studied in the domesticated guinea pig (Cavia aperea f. porcellus) after dissecting pregnant females, but there are no studies describing the fetal growth in their wild progenitor, the wild guinea pig (C aperea). In this study, 50 pregnancies of wild guinea pig sows were investigated using modern ultrasound technique. The two most common fetal growth parameters (biparietal diameter [BPD] and crown-rump-length [CRL]) and uterine position were measured. Data revealed similar fetal growth patterns in the wild guinea pig and domesticated guinea pig in the investigated gestation period, although they differ in reproductive milestones such as gestation length (average duration of pregnancy 68 days), average birth weight, and litter mass. In this study, pregnancy lasted on average 60.2 days with a variance of less than a day (0.96 days). The measured fetal growth parameters are strongly correlated with each (R = 0.91; P < 0.001) other and with gestational age (BPD regression equation y = 0.04x - 0.29; P < 0.001 and CRL regression equation y = 0.17x - 2.21; P < 0.01). Furthermore, fetuses in the most frequent uterine positions did not differ in their growth parameters and were not influenced by the mother ID. Our results imply that ultrasound measurement of a single fetal growth parameter is sufficient to reliably estimate gestational age in the wild guinea pig.

Global emissions of terpenoid VOCs from terrestrial vegetation in the last millennium

We investigated the millennial variability (1000 A.D.-2000 A.D.) of global biogenic volatile organic compound (BVOC) emissions by using two independent numerical models: The Model of Emissions of Gases and Aerosols from Nature (MEGAN), for isoprene, monoterpene, and sesquiterpene, and Lund-Potsdam-Jena-General Ecosystem Simulator (LPJ-GUESS), for isoprene and monoterpenes. We found the millennial trends of global isoprene emissions to be mostly affected by land cover and atmospheric carbon dioxide changes, whereas monoterpene and sesquiterpene emission trends were dominated by temperature change. Isoprene emissions declined substantially in regions with large and rapid land cover change. In addition, isoprene emission sensitivity to drought proved to have significant short-term global effects. By the end of the past millennium MEGAN isoprene emissions were 634 TgC yr^-1 (13% and 19% less than during 1750-1850 and 1000-1200, respectively), and LPJ-GUESS emissions were 323 TgC yr^-1(15% and 20% less than during 1750-1850 and 1000-1200, respectively). Monoterpene emissions were 89 TgC yr^-1(10% and 6% higher than during 1750-1850 and 1000-1200, respectively) in MEGAN, and 24 TgC yr^-1 (2% higher and 5% less than during 1750-1850 and 1000-1200, respectively) in LPJ-GUESS. MEGAN sesquiterpene emissions were 36 TgC yr^-1(10% and 4% higher than during 1750-1850 and 1000-1200, respectively). Although both models capture similar emission trends, the magnitude of the emissions are different. This highlights the importance of building better constraints on VOC emissions from terrestrial vegetation.

Primary and secondary organics in the tropical Amazonian rainforest aerosols: chiral analysis of 2-methyltetraols

This work presents the application of a new method to facilitate the distinction between biologically produced (primary) and atmospherically produced (secondary) organic compounds in ambient aerosols based on their chirality. The compounds chosen for this analysis were the stereomers of 2-methyltetraols, (2R,3S)- and (2S,3R)-methylerythritol, (l- and d-form, respectively), and (2S,3S)- and (2R,3R)-methylthreitol (l- and d-form), shown previously to display some enantiomeric excesses in atmospheric aerosols, thus to have at least a partial biological origin. In this work PM10 aerosol fractions were collected in a remote tropical rainforest environment near Manaus, Brazil, between June 2008 and June 2009 and analysed. Both 2-methylerythritol and 2-methylthreitol displayed a net excess of one enantiomer (either the l- or the d-form) in 60 to 72% of these samples. These net enantiomeric excesses corresponded to compounds entirely biological but accounted for only about 5% of the total 2-methyltetrol mass in all the samples. Further analysis showed that, in addition, a large mass of the racemic fractions (equal mixtures of d- and l-forms) was also biological. Estimating the contribution of secondary reactions from the isomeric ratios measured in the samples (=ratios 2-methylthreitol over 2-methylerythritol), the mass fraction of secondary methyltetrols in these samples was estimated to a maximum of 31% and their primary fraction to a minimum of 69%. Such large primary fractions could have been expected in PM10 aerosols, largely influenced by biological emissions, and would now need to be investigated in finer aerosols. This work demonstrates the effectiveness of chiral and isomeric analyses as the first direct tool to assess the primary and secondary fractions of organic aerosols.

Photoperiodic effects on reproductive development in male cavies (Cavia aperea)

Age at maturity is a particularly important life history parameter, as it predicts potential life time reproductive success in many small mammal species. Animals should therefore optimize the timing of maturation by reacting to environmental stimuli that predict future environmental conditions. Photoperiod often reliably predicts ecological conditions. Animals born into a photoperiod indicating favorable conditions (spring, summer) may mature earlier and at a lower weight than animals born into conditions indicating unfavorable conditions (autumn, winter). So far most work was done on small, altricial rodent species and we still lack knowledge about their precocial relatives. Precocial animals are born much further developed than altricials and might show less plasticity in their ontogenetic trajectory than the latter. We tested the influence of photoperiod simulated by increasing (spring) or decreasing (autumn) light in climate chambers on important life history parameters in a medium sized rodent, the highly precocial cavy (Cavia aperea). We wanted to determine whether photoperiod influences timing of maturation and early growth in male cavies and whether patterns of testosterone in blood are reflected by patterns of testosterone metabolites in feces.Males born into simulated spring grew faster and matured at an earlier age than males born into simulated autumn conditions. Patterns of testosterone in blood correlated with testosterone metabolites measured in feces. Male cavies strongly react to predictive photoperiod cues by adjusting growth and timing of maturation as we found previously for females, corroborating the importance of seasonal cues for adjustments of life history.

Persisting myelin oligodendrocyte glycoprotein antibodies in aquaporin-4 antibody negative pediatric neuromyelitis optica

BACKGROUND

Recently we showed that antibodies to myelin oligodendrocyte glycoprotein (MOG) can be found in aquaporin-4 (AQP4)-immunoglobulin (IgG) seronegative pediatric and adult patients with definite and high-risk neuromyelitis optica (NMO).

OBJECTIVE

The purpose of this study was to describe the clinical characteristics and temporal dynamics of MOG-IgG in AQP4-IgG seronegative pediatric patients presenting with definite NMO.

METHODS

Children with definite NMO who were referred for further testing of serum antibodies for AQP4 and MOG with a cell-based assay were included in this study. Clinical disease course, cerebrospinal fluid and magnetic resonance imaging (MRI) studies of these patients were reviewed.

RESULTS

Between 2008 and 2012 eight children who fulfilled the diagnostic criteria of definite NMO were recruited. Two children with definite NMO tested positive for AQP4-IgG but were negative for MOG-IgG antibodies. Three children had an absence of AQP4-IgG and MOG-IgG antibodies. Three children with definite NMO had high titers of serum MOG-IgG antibodies (≥1: 160), but no AQP4-directed humoral immune response. Longitudinal analysis of serum samples of the latter three children showed persisting high MOG-IgG titers over time.

CONCLUSION

Pediatric patients presenting with clinical symptoms and MRI findings highly suggestive of NMO but with high and persisting MOG-IgG antibody titers are most likely to represent a distinct subgroup of acute demyelinating diseases with important clinical and therapeutic implications.