Autochthonous West Nile Virus Infection Outbreak in Humans (Asti, Piedmont, Italy, August-October 2018) and Long-Term Sequelae Follow-Up.

West Nile virus (WNV) infection is a reemerging zoonosis recently provoking significant outbreaks throughout Europe. During the summer of 2018, the number of WNV infections rose with a peak of new diagnoses of West Nile neuro-invasive disease (WNND). Most of the Italian cases were clustered in the Po River Valley. We present a case series of nine patients with WNV infection admitted to the Cardinal Massaia Hospital from 30 August 2018 to 1 October 2018. Demographic, immunovirological, clinical and therapeutic data are shown, and a report on clinical sequelae from the subsequent follow-up in patients with WNV and WNND. We showed the clinical, radiological and biochemical characteristics of WNV-infected patients. The risk factors and the clinical presentation of WNV in most patients in our case series were typical of that described in the literature, although, despite the high morbidity and mortality of WNND, we showed survival of 100% and long-term sequelae in only three patients. Environmental conditions may be essential in WNV outbreaks, and WNND can be clinically neurological multiform. Our long-lasting follow-up with clinical or radiological monitoring confirmed the morbidity of long-term neurological sequelae after WNND. Further studies are needed to investigate the epidemiology and physiopathology of bacterial superinfections after WNV infection.

A multifaceted ecological assessment reveals the invasion of the freshwater red macroalga Montagnia macrospora (Batrachospermales, Rhodophyta) in Taiwan.

Invasive freshwater macroalgae are rarely described. Montagnia macrospora is a freshwater red alga introduced from South America to East Asia via the global aquarium trade. The earliest occurrence record of this alga in Taiwan is dated 2005. To determine whether M. macrospora has become invasive in Taiwan and to understand the traits that facilitated its invasion, we took a multifaceted approach that combines examination of ecological background and population genetic analysis. Our island-wide survey showed that M. macrospora is widespread in the field across Taiwan, where the climate greatly differs from that of South America, and can self-sustain for nearly a decade. Our population genetic analysis revealed a lack of genetic diversity of M. macrospora in Taiwan, consistent with the hypothesis that the alga expanded through asexual reproduction. Moreover, during our long-term ecological assessments and field surveys, we observed that M. macrospora is an ecological generalist that can survive in a wide range of temperature, pH, illumination, and nutrient enrichment. Taken together, our data suggest that M. macrospora has successfully invaded the freshwater ecosystems of Taiwan, likely due to its ability to disperse asexually and to grow under broad environmental conditions. We hope that our study brings attention to invasive freshwater algae, which have been overlooked in conservation planning and management.

Pitfalls of Computed Tomography in the Coronavirus 2019 (COVID-19) Era: A New Perspective on Ground-Glass Opacities.

Aim To study ground-glass opacities (GGO) not only from the coronavirus 2019 (COVID-19) pneumonia" perspective but also as a radiological presentation of other pathologies with comparable features. Methods We enrolled 33 patients admitted to Policlinico Universitario G. B. Rossi who underwent non-contrast-enhanced (NCE) or contrast-enhanced (CE) chest computed tomography (CT) between March 12 and April 12. All patients with CT-detected ground-glass opacity (GGO) were included. All patients resulted as COVID-19 negative at the reverse transcription-polymerase chain reaction (RT-PCR) assay. We studied the different pathologies underlying GGO features: neoplastic diseases and non-neoplastic diseases (viral pneumonias, interstitial pneumonias, and cardiopulmonary diseases) in order to avoid pitfalls and to reach the correct diagnosis. Results All CT scans detected GGOs. Symptomatic patients were 25/33 (75.7%). At the clinical presentation, they reported fever and dry cough; in six out of 25 cases, dyspnea was also reported (24%). Thirty-three (33; 100%) showed GGO at CT: 15/33 (45.45%) presented pure GGO, and 18/33 (54.54%) showed GGO with consolidation. The RT-PCR assay was negative in 100%. We investigated other potential underlying diseases to explain imaging features: neoplastic causes (8/33, 24.24%) and non-neoplastic causes, in particular, infectious pneumonias (16/33, 48,48 %, viral and fungal), interstitial pneumonias (4/33, 12,12%), and cardio-pulmonary disease (5/33, 15,15%). Conclusions GGO remains a diagnostic challenge. Although CT represents a fundamental diagnostic tool because of its sensitivity, it still needs to be integrated with clinical data to achieve the best clinical management. In the presence of typical imaging features (e.g. GGO and consolidation), the radiologist should focus on the pandemic and manage a suspect patient as COVID-19 positive until proven to be negative.

Serafino Zappacosta: An Enlightened Mentor and Educator.

With this article, the authors aim to honor the memory of Serafino Zappacosta, who had been their mentor during the early years of their career in science. The authors discuss how the combination of Serafino Zappacosta's extraordinary commitment to teaching and passion for science created a fostering educational environment that led to the creation of the "Ruggero Ceppellini Advanced School of Immunology." The review also illustrates how the research on the MHC and the inspirational scientific context in the Zappacosta's laboratory influenced the authors' early scientific interests, and subsequent professional work as immunologists.

The fire ant social supergene is characterized by extensive gene and transposable element copy number variation.

In the fire ant Solenopsis invicta, a supergene composed of ~600 genes and having two variants, SB and Sb, regulates colony social form. In single queen colonies, all individuals carry only the SB allele, while in multiple queen colonies, some individuals carry the Sb allele. In this study, we characterized genes with copy number variation between SB and Sb-carrying individuals. We showed extensive acquisition of gene duplicates in the Sb genome, with some likely involved in polygyne-related phenotypes. We found 260 genes with copy number differences between SB and Sb, of which 239 have greater copy number in Sb. We observed transposable element (TE) accumulation on Sb, likely due to the accumulation of repetitive elements on the nonrecombining chromosome. We found a weak correlation between TE copy number and differential expression, suggesting some TEs may still be proliferating in Sb while many of the duplicated TEs have presumably been silenced. Among the 115 non-TE genes with higher copy in Sb, enzymes responsible for cuticular hydrocarbon synthesis were highly represented. These include a desaturase and an elongase, both potentially responsible for differential queen odour and likely beneficial for polygyne ants. These genes seem to have translocated into the supergene from other chromosomes and proliferated by multiple duplication events. While the presence of TEs in supergenes is well documented, little is known about duplication of non-TE genes and their possible adaptive role. Overall, our results suggest that gene duplications may be an important factor leading to monogyne and polygyne ant societies.

Has gene expression neofunctionalization in the fire ant antennae contributed to queen discrimination behavior?

Queen discrimination behavior in the fire ant Solenopsis invicta maintains its two types of societies: colonies with one (monogyne) or many (polygyne) queens, yet the underlying genetic mechanism is poorly understood. This behavior is controlled by two supergene alleles, SB and Sb, with ~600 genes. Polygyne workers, having either the SB/SB or SB/Sb genotype, accept additional SB/Sb queens into their colonies but kill SB/SB queens. In contrast, monogyne workers, all SB/SB, reject all additional queens regardless of genotype. Because the SB and Sb alleles have suppressed recombination, determining which genes within the supergene mediate this differential worker behavior is difficult. We hypothesized that the alternate worker genotypes sense queens differently because of the evolution of differential expression of key genes in their main sensory organ, the antennae. To identify such genes, we sequenced RNA from four replicates of pooled antennae from three classes of workers: monogyne SB/SB, polygyne SB/SB, and polygyne SB/Sb. We identified 81 differentially expressed protein-coding genes with 13 encoding potential chemical metabolism or perception proteins. We focused on the two odorant perception genes: an odorant receptor SiOR463 and an odorant-binding protein SiOBP12. We found that SiOR463 has been lost in the Sb genome. In contrast, SiOBP12 has an Sb-specific duplication, SiOBP12b', which is expressed in the SB/Sb worker antennae, while both paralogs are expressed in the body. Comparisons with another fire ant species revealed that SiOBP12b' antennal expression is specific to S. invicta and suggests that queen discrimination may have evolved, in part, through expression neofunctionalization.

Transcriptomic response in Acropora muricata under acute temperature stress follows preconditioned seasonal temperature fluctuations.

OBJECTIVE: Global climate change has resulted in the decline of health and condition of various coral reefs worldwide. Here, we describe expression profiles of Acropora muricata collected during opposing seasons in Otsuki, Kochi, Japan to define the capacity of corals to cope with changing environmental conditions. Coral communities in Otsuki experience large temperature fluctuations between the winter (~ 16 °C) and summer (~ 27 °C). RESULTS: Coral nubbins that were collected in the summer showed no change in photochemical efficiency when exposed to thermal or cold stress, while winter samples showed a decrease in photochemical health when subjected to thermal stress. Under cold stress, corals that were collected in the summer showed an up-regulation of actin-related protein and serine/threonine protein kinase, while corals collected during the winter did not show any cellular stress. On the other hand, under thermal stress, the most notable change was the up-regulation of phosphoenolpyruvate carboxykinase in corals that were collected during the winter season. Our observations in the differential genes expressed under temperature-derived stress suggest that A. muricata from Kochi may maintain physiological resilience due to the frequently encountered environmental stress, and this may play a role in the coral's thermal tolerance.

Dried plasma/blood spots for monitoring antiretroviral treatment efficacy and pharmacokinetics: a cross-sectional study in rural Burundi.

AIMS: In limited resource settings monitoring antiretroviral (ARV) treatment efficacy is restrained by the lack of access to technological equipment. The aim of the study was to assess the use of dried plasma (DPS) and blood spots (DBS) to facilitate ARV monitoring in remote settings where clinical monitoring is the primary strategy. METHODS: A cross-sectional study in HIV-positive ARV-treated patients in Kiremba, Burundi was performed. DBS were used for HIV-1 viral load (limit of the assay 250 copies ml(-1)) and genotypic drug resistance tests and dried plasma spots were used for concentration measurements. RESULTS: Three hundred and seven patients [201 female (88.6%), 14 children (4.5%)] were enrolled. HIV-1 viral load was <250, 250-1000 and >1000 copies ml(-1) in 250 (81.7%), 33 (10.8%) and 23 patients (7.5%). Eleven samples out of 23 were successfully amplified revealing nucleoside reverse transcriptase inhibitor (NRTI) and non-nucleoside reverse transcriptase inhibitor (NNRTI)-resistance associated mutations [in seven (58.3%) and six patients (50%)]. Nevirapine trough concentrations were <3000 ng ml(-1) in 28/189 patients (14.8%) and efavirenz 12 h concentrations were <1000 ng ml(-1) in 2/16 patients (12.5%). Children and patients with nevirapine exposure <3000 ng ml(-1) presented a higher risk of viral replication. CONCLUSIONS: Viral loads <250 copies ml(-1) were observed in 81.7% of patients (83.6% adults and 42.9% children). Children and patients with low nevirapine concentrations had higher risk of viral replication. Dried blood and plasma spots may be useful for monitoring HIV-positive patients including viral load and drug level measurement as part of treatment management in remote areas.

[Quality of sleep and selective attention in university students: descriptive cross-sectional study]. / Calidad de sueño y atención selectiva en estudiantes universitarios: estudio descriptivo transversal.

INTRODUCTION: Sleep quality not only refers to sleeping well at night, but also includes appropriate daytime functioning. Poor quality of sleep can affect a variety of attention processes. PURPOSE: The aim of this investigation was to evaluate the relationship between the perceived quality of sleep and selective focus in a group of college students. METHODS: A descriptive cross-sectional study was carried out in a group of 52 Argentinian college students of the Universidad Adventista del Plata. The Pittsburgh Sleep Quality Index, the Continuous Performance Test and the Trail Making Test were applied. RESULTS: The main results indicate that students sleep an average of 6.48 hours. Generally half of the population tested had a good quality of sleep. However, the dispersion seen in some components demonstrates the heterogeneity of the sample in these variables. It was observed that the evaluated attention processes yielded different levels of alteration in the total sample: major variability in the process of process and in the divided-attention processes were detected. A lower percentage of alteration was observed in the process of attention support. CONCLUSION: Poor quality of sleep has more impact in the sub processes with greater participation of corticocortical circuits (selective and divided attention) and greater involvement of the prefrontal cortex. Fewer difficulties were found in the attention-support processes that rely on subcortical regions and have less frontal involvement.

INTRODUCCIÓN: La calidad de sueño no sólo se refiere al hecho de dormir bien durante la noche, sino que incluye también un buen funcionamiento diurno. La mala calidad de sueño puede afectar distintos subprocesos de la atención. El objetivo de la presente investigación fue evaluar la relación existente entre la calidad de sueño percibida y la atención selectiva en estudiantes universitarios. MÉTODOS: Se realizó un estudio descriptivo, transversal que incluyó a un grupo de 52 estudiantes argentinos de la Universidad Adventista del Plata. Se aplicaron el Índice de Calidad de Sueño de Pittsburgh y para evaluar problemas de atención, el Continuous Performance Test y el Trail Making Test. RESULTADOS: Los principales resultados obtenidos indicaron que los alumnos duermen un promedio de 6,48 horas. En general la mitad de la población evaluada presentaba una buena calidad de sueño, aunque las dispersiones en algunos componentes demuestran la heterogeneidad de la muestra en estas variables. Se observó que los procesos atencionales evaluados arrojaron diferentes niveles de alteración en la muestra total: se detectó mayor alteración en el proceso selectivo, en forma intermedia el proceso de atención dividida y se observó un porcentaje menor de alteraciones del proceso de sostenimiento atencional. CONCLUSIONES: La mala calidad de sueño tiene mayor incidencia en los subprocesos con mayor participación de circuitos córtico-corticales (atención selectiva y dividida) y mayor participación de la corteza prefrontal. Se hallaron menores dificultades en el sostenimiento atencional que depende, mayormente, de regiones subcorticales y tiene menor participación frontal.

Doors are closing on early development in corals facing climate change.

Marine invertebrates are particularly vulnerable to climatic anomalies in early life history stages because of the time spent in the water column. Studies have focused on the effect of seawater temperature on fertilization, development, and larval stages in corals; however, none of them show comparative results along an environmental gradient. In this study, we show that temperatures in the range of 15-33 °C have strong effects on fertilization rates and embryonic stages of two coral species, Acropora muricata in the subtropical environment and Acropora hyacinthus in subtropical and temperate environments. Deformations after the first cleavage stages were observed at low (15 °C) and high (33 °C) temperatures. Development was delayed by 6-7 h in the slightly non-optimal temperature of 20 °C. We found significant differences in fertilization rates and responses of embryos from different latitudes, with temperate corals being more sensitive to extremely hot temperatures and vice versa. We hypothesize that the coral development is restricted to a narrow temperature range and deviation outside this window could inhibit a species' continuance and ecological success. Thus, it would have significant negative effects on adult populations and communities, playing a role in future of coral reef survival.

DNA barcoding reveals the coral "laboratory-rat", Stylophora pistillata encompasses multiple identities.

Stylophora pistillata is a widely used coral "lab-rat" species with highly variable morphology and a broad biogeographic range (Red Sea to western central Pacific). Here we show, by analysing Cytochorme Oxidase I sequences, from 241 samples across this range, that this taxon in fact comprises four deeply divergent clades corresponding to the Pacific-Western Australia, Chagos-Madagascar-South Africa, Gulf of Aden-Zanzibar-Madagascar, and Red Sea-Persian/Arabian Gulf-Kenya. On the basis of the fossil record of Stylophora, these four clades diverged from one another 51.5-29.6 Mya, i.e., long before the closure of the Tethyan connection between the tropical Indo-West Pacific and Atlantic in the early Miocene (16-24 Mya) and should be recognised as four distinct species. These findings have implications for comparative ecological and/or physiological studies carried out using Stylophora pistillata as a model species, and highlight the fact that phenotypic plasticity, thought to be common in scleractinian corals, can mask significant genetic variation.

Molecular evidence shows low species diversity of coral-associated hydroids in Acropora corals.

A novel symbiosis between scleractinians and hydroids (Zanclea spp.) was recently discovered using taxonomic approaches for hydroid species identification. In this study, we address the question whether this is a species-specific symbiosis or a cosmopolitan association between Zanclea and its coral hosts. Three molecular markers, including mitochondrial 16S and nuclear 28S ribosomal genes, and internal transcribed spacer (ITS), were utilized to examine the existence of Zanclea species from 14 Acropora species and 4 other Acroporidae genera including 142 coral samples collected from reefs in Kenting and the Penghu Islands, Taiwan, Togian Island, Indonesia, and Osprey Reef and Orpheus Island on the Great Barrier Reef, Australia. Molecular phylogenetic analyses of the 16S and 28S genes showed that Acropora-associated Zanclea was monophyletic, but the genus Zanclea was not. Analysis of the ITS, and 16S and 28S genes showed either identical or extremely low genetic diversity (with mean pairwise distances of 0.009 and 0.006 base substitutions per site for the 16S and 28S genes, respectively) among Zanclea spp. collected from diverse Acropora hosts in different geographic locations, suggesting that a cosmopolitan and probably genus-specific association occurs between Zanclea hydroids and their coral hosts.

Valoración de índices plaquetarios en las trombocitopenias / Valuation of platelet índices in thrombocytopenia / Avaliagáo de índices plaquetários nas trombocitopenias

El objetivo de este trabajo fue determinar la utilidad clínica de los índices plaquetarios en la caracterización etiológica de las trombocitopenias. Se trata de un estudio descriptivo, retrospectivo y transversal. En pacientes controles se establecieron valores de referencia para número de plaquetas e índices plaquetarios, y éstos se evaluaron en pacientes donde coexistía trombocitopenia con algún desorden oncohematológico (linfoma no Hodgkin, linfoma Hodgkin, leucemia aguda, leucemia crónica, síndrome mielodisplásico, púrpura trombocitopénica inmune). La evaluación de laboratorio fue realizada al momento del diagnóstico, aún libre de tratamiento. En los casos de Púrpura Inmune (disminución de Volumen Plaquetario - Plaquetocrito, y aumento de Amplitud Plaquetaria); Leucemia Mieloide Crónica (aumento de la Amplitud Plaquetaria) y Linfoma no Hodgkin o Síndrome Mielodisplásico (disminución del Plaquetocrito), los índices plaquetarios podrían ser usados como herramienta diagnóstica orientadora. En cambio, no podrían contribuir al momento de diferenciar entre leucemias agudas, dado que no presentan diferencias significativas. Frente a un diagnóstico presuntivo de síndrome mielodiasplásico o leucemia mieloide aguda, el valor de Volumen Plaquetario Medio (VPM) podría contribuir como herramienta orientadora al diagnóstico, ya que sería más bajo en la leucemia aguda. El análisis de los resultados sugiere que en la práctica clínica los índices plaquetarios podrían contribuir de un modo significativo a la confirmación del diagnóstico.

The aim of this study was to determine the clinical utility of platelet indices in the etiological characterization of thrombocytopenia. It was a descriptive, retrospective and cross-sectional study. In control patients, reference values (platelet count and platelet indices) were established and they were used to assess platelet indices in patients where thrombocytopenia coexisted with some oncohematologic disorders (non-Hodgkin Lymphoma, Hodgkin Lymphoma, acute leukemia, chronic leukemia, myelodysplastic syndrome, immune thrombocytopenic purpura). Laboratory evaluation was performed at still treatment-free diagnosis. In the cases of Immune Purpura, (decreased platelet volume- plateletcrit, and increased platelet distribution width) Chronic Myeloid Leukemia (increased platelet distribution width) and non-Hodgkin lymphoma or myelodysplastic syndrome (decreased plateletcrit), platelet indices could be used as a "guiding diagnostic tool". However, they could not contribute to the differenciation between acute leukemias since they do not present any significant differences. In view of a presumptive diagnosis of mielodysplastic syndrome or acute myeloid leukemia, mean platelet value (MPV) could contribute to the diagnosis, since it would be lower in acute leukemia. The analysis of the results suggests that in clinical practice, platelet indices may contribute significantly to the confirmation of the diagnosis.

O objetivo deste trabalho foi determinar a utilidade clínica dos índices plaquetários na caracterizagáo etiológica das trombocitopenias. Trata-se de um estudo descritivo, retrospectivo e transversal. Em pacientes controle foram estabelecidos valores de referencia para número de plaquetas e índices plaquetários, e eles foram avaliados em pacientes onde coexistia trombocitopenia com alguma desordem onco-hematológica (linfoma náo Hodgkin, linfoma Hodgkin, leucemia aguda, leucemia crónica, síndrome mielodisplásica, púrpura trombocitopenia imune). A avaliagáo de laboratório foi realizada no momento do diagnóstico, ainda livre de tratamento. Nos casos de Púrpura Imune (diminuigáo de Volume Plaquetario - Plaquetócrito, e aumento de Amplitude Plaquetária); Leucemia Mieloide Crónica (aumento da Amplitude Plaquetária) e Linfoma náo Hodgkin ou Síndrome Mielodisplásica (diminuigáo do Plaquetócrito), os índices plaquetários poderiam ser usados como ferramenta diagnóstica orientadora. Entretanto, náo poderiam contribuir no momento de diferenciar entre leucemias agudas, visto que náo apresentam diferengas significativas. Diante de um diagnóstico presuntivo de síndrome mielodiasplásica ou leucemia mieloide aguda, o valor de Volume Plaquetário Médio (VPM) poderia contribuir como ferramenta orientadora para o diagnóstico, devido a que seria mais baixo na leucemia aguda. A análise dos resultados sugere que na prática clínica os índices plaquetários poderiam contribuir de um modo significativo para a confirmagáo do diagnóstico.

An oscillatory switch in mTOR kinase activity sets regulatory T cell responsiveness.

There is a discrepancy between the in vitro anergic state of CD4(+)CD25(hi)FoxP3(+) regulatory T (Treg) cells and their in vivo proliferative capability. The underlying mechanism of this paradox is unknown. Here we show that the anergic state of Treg cells depends on the elevated activity of the mammalian target of rapamycin (mTOR) pathway induced by leptin: a transient inhibition of mTOR with rapamycin, before T cell receptor (TCR) stimulation, made Treg cells highly proliferative in the absence of exogenous interleukin-2 (IL-2). This was a dynamic and oscillatory phenomenon characterized by an early downregulation of the leptin-mTOR pathway followed by an increase in mTOR activation necessary for Treg cell expansion to occur. These data suggest that energy metabolism, through the leptin-mTOR-axis, sets responsiveness of Treg cells that use this information to control immune tolerance and autoimmunity.

Tipranavir (TPV) genotypic inhibitory quotient predicts virological response at 48 weeks to TPV-based salvage regimens.

The virological response (VR) to a tipranavir-ritonavir (TPV-RTV)-based regimen had been shown to be associated with a number of mutations in the protease gene, the use of enfuvirtide (T20), and the TPV phenotypic inhibitory quotient (IQ). The role of the TPV genotypic IQ (gIQ) has not yet been fully investigated. The aim of our study was to evaluate the relationship between the TPV gIQ and the VR at 48 weeks to TPV-based salvage regimens. Patients placed on regimens containing two nucleoside reverse transcriptase inhibitors plus TPV-RTV 500/200 mg twice a day with or without T20 were prospectively studied. Regular follow-up was performed over the study period. VR, considered a viral load (VL) decrease of >or=1 log unit and/or the achievement of <50 copies/ml with no VL rebound of >0.5 log unit compared to the maximal VL decrease at week 48, was assessed. Thirty-eight patients who had received multiple drugs were included. At week 48 the VL decrease was -1.48 (interquartile range [IQR], -2.88 to -0.48), 15 patients (39.5%) had VLs of <50 copies/ml, and the CD4+ cell count increase was 37 cells/mm3 (IQR, -30 to +175). Twenty subjects (52.6%) achieved VRs. The TPV gIQ and optimized background score (OBS) were independently associated with higher VL decreases. The TPV gIQ and OBS were also independent predictors of a VR at week 48. TPV gIQ and OBS cutoff values of 14,500 and 2, respectively, were associated with a higher rate of VR. The TPV gIQ was shown to be able to predict the VR at 48 weeks to TPV-containing salvage regimens better than the TPV trough concentration or TPV-associated mutations alone. A possible TPV gIQ cutoff value of 14,500 for reaching a VR at week 48 was suggested. Further studies are needed in order to evaluate the calculation of TPV gIQ as a new tool for the optimization of TPV-based salvage therapy.

A key role of leptin in the control of regulatory T cell proliferation.

We report here that leptin can act as a negative signal for the proliferation of human naturally occurring Foxp3(+)CD4(+)CD25(+) regulatory T (T(reg)) cells. Freshly isolated T(reg) cells produced leptin and expressed high amounts of leptin receptor (ObR). In vitro neutralization with leptin monoclonal antibody (mAb), during anti-CD3 and anti-CD28 stimulation, resulted in T(reg) cell proliferation, which was interleukin-2 (IL-2) dependent. T(reg) cells that proliferated in the presence of leptin mAb had increased expression of Foxp3 and remained suppressive. The phenomena appeared secondary to leptin signaling via ObR and, importantly, leptin neutralization reversed the anergic state of the T(reg) cells, as indicated by downmodulation of the cyclin-dependent kinase inhibitor p27 (p27(kip1)) and the phosphorylation of the extracellular-related kinases 1 (ERK1) and ERK2. Together with the finding of enhanced proliferation of T(reg) cells observed in leptin- and ObR-deficient mice, these results suggest a potential for therapeutic interventions in immune and autoimmune diseases.

Clinical and molecular genetic spectrum of congenital deficiency of the leptin receptor.

BACKGROUND: A single family has been described in which obesity results from a mutation in the leptin-receptor gene (LEPR), but the prevalence of such mutations in severe, early-onset obesity has not been systematically examined. METHODS: We sequenced LEPR in 300 subjects with hyperphagia and severe early-onset obesity, including 90 probands from consanguineous families, and investigated the extent to which mutations cosegregated with obesity and affected receptor function. We evaluated metabolic, endocrine, and immune function in probands and affected relatives. RESULTS: Of the 300 subjects, 8 (3%) had nonsense or missense LEPR mutations--7 were homozygotes, and 1 was a compound heterozygote. All missense mutations resulted in impaired receptor signaling. Affected subjects were characterized by hyperphagia, severe obesity, alterations in immune function, and delayed puberty due to hypogonadotropic hypogonadism. Serum leptin levels were within the range predicted by the elevated fat mass in these subjects. Their clinical features were less severe than those of subjects with congenital leptin deficiency. CONCLUSIONS: The prevalence of pathogenic LEPR mutations in a cohort of subjects with severe, early-onset obesity was 3%. Circulating levels of leptin were not disproportionately elevated, suggesting that serum leptin cannot be used as a marker for leptin-receptor deficiency. Congenital leptin-receptor deficiency should be considered in the differential diagnosis in any child with hyperphagia and severe obesity in the absence of developmental delay or dysmorphism.

Differential regulation of metabolic, neuroendocrine, and immune function by leptin in humans.

To elucidate whether the role of leptin in regulating neuroendocrine and immune function during short-term starvation in healthy humans is permissive, i.e., occurs only when circulating leptin levels are below a critical threshold level, we studied seven normal-weight women during a normoleptinemic-fed state and two states of relative hypoleptinemia induced by 72-h fasting during which we administered either placebo or recombinant methionyl human leptin (r-metHuLeptin) in replacement doses. Fasting for 72 h decreased leptin levels by approximately = 80% from a midphysiologic (14.7 +/- 2.6 ng/ml) to a low-physiologic (2.8 +/- 0.3 ng/ml) level. Administration of r-metHuLeptin during fasting fully restored leptin to physiologic levels (28.8 +/- 2.0 ng/ml) and reversed the fasting-associated decrease in overnight luteinizing hormone pulse frequency but had no effect on fasting-induced changes in thyroid-stimulating hormone pulsatility, thyroid and IGF-1 hormone levels, hypothalamic-pituitary-adrenal and renin-aldosterone activity. FSH and sex steroid levels were not altered. Short-term reduction of leptin levels decreased the number of circulating cells of the adaptive immune response, but r-metHuLeptin did not have major effects on their number or in vitro function. Thus, changes of leptin levels within the physiologic range have no major physiologic effects in leptin-replete humans. Studies involving more severe and/or chronic leptin deficiency are needed to precisely define the lower limit of normal leptin levels for each of leptin's physiologic targets.

Leptin neutralization interferes with pathogenic T cell autoreactivity in autoimmune encephalomyelitis.

Recent evidence has indicated that leptin, an adipocyte-secreted hormone belonging to the helical cytokine family, significantly influences immune and autoimmune responses. We investigate here the mechanisms by which in vivo abrogation of leptin effects protects SJL/J mice from proteolipid protein peptide PLP(139-151)-induced EAE, an animal model of MS. Blockade of leptin with anti-leptin Abs or with a soluble mouse leptin receptor chimera (ObR:Fc), either before or after onset of EAE, improved clinical score, slowed disease progression, reduced disease relapses, inhibited PLP(139-151)-specific T cell proliferation, and switched cytokine secretion toward a Th2/regulatory profile. This was also confirmed by induction of forkhead box p3 (Foxp3) expression in CD4 T cells in leptin-neutralized mice. Importantly, anti-leptin treatment induced a failure to downmodulate the cyclin-dependent kinase inhibitor p27 (p27) in autoreactive CD4 T cells. These effects were associated with increased tyrosine phosphorylation of both ERK1/2 and STAT6. Taken together, our data provide what we believe is a new molecular basis for leptin antagonism in EAE and envision novel strategies of leptin-based molecular targeting in the disease.