Sensitized Triplet-Triplet Annihilation in Nanostructured Polymeric Scintillators Allows for Pulse Shape Discrimination.

Scintillating materials emit light when exposed to ionizing radiation or particles and are used for the detection of nuclear threats, medical imaging, high-energy physics, and other usages. For some of these applications, it is vital to distinguish neutrons and charged particles from γ-rays. This is achievable by pulse shape discrimination (PSD), a time-gated technique, which exploits that the scintillation kinetics can depend on the nature of the incident radiation. However, it proves difficult to realize efficient PSD with plastic scintillators, which have several advantages over liquid or crystalline scintillating materials, including mechanical robustness and shapeability. It is shown here that sensitive and rapid PSD is possible with nanostructured polymer scintillators that consist of a solid polymer matrix and liquid nanodomains in which an organic dye capable of triplet-triplet annihilation (TTA) is dissolved. The liquid nature of the nanodomains renders TTA highly efficient so that delayed fluorescence can occur at low energy density. The nanostructured polymer scintillators allow discriminating α particles, neutrons, and γ-rays with a time response that is better than that of commercial scintillators. Exploiting that the liquid nanodomains can facilitate energy transfer processes otherwise difficult to realize in solid polymers, an auxiliary triplet sensitizer is incorporated. This approach further increases the scintillator's sensitivity toward α particles and neutrons and other high-energy processes where localized interactions are involved.

Noninvasive Treatment of Alzheimer's Disease with Scintillating Nanotubes.

Effective and accessible treatments for Alzheimer's disease (AD) are urgently needed. Soluble Aß oligomers are identified as neurotoxic species in AD and targeted in antibody-based drug development to mitigate cognitive decline. However, controversy exists concerning their efficacy and safety. In this study, an alternative strategy is proposed to inhibit the formation of Aß oligomers by selectively oxidizing specific amino acids in the Aß sequence, thereby preventing its aggregation. Targeted oxidation is achieved using biocompatible and blood-brain barrier-permeable multicomponent nanoscintillators that generate singlet oxygen upon X-ray interaction. Surface-modified scintillators interact selectively with Aß and, upon X-ray irradiation, inhibit the formation of neurotoxic aggregates both in vitro and in vivo. Feeding transgenic Caenorhabditis elegans expressing human Aß with the nanoscintillators and subsequent irradiation with soft X-ray reduces Aß oligomer levels, extends lifespan, and restores memory and behavioral deficits. These findings support the potential of X-ray-based therapy for AD and warrant further development.

Energy Partitioning in Multicomponent Nanoscintillators for Enhanced Localized Radiotherapy.

Multicomponent nanomaterials consisting of dense scintillating particles functionalized by or embedding optically active conjugated photosensitizers (PSs) for cytotoxic reactive oxygen species (ROS) have been proposed in the last decade as coadjuvant agents for radiotherapy of cancer. They have been designed to make scintillation-activated sensitizers for ROS production in an aqueous environment under exposure to ionizing radiations. However, a detailed understanding of the global energy partitioning process occurring during the scintillation is still missing, in particular regarding the role of the non-radiative energy transfer between the nanoscintillator and the conjugated moieties which is usually considered crucial for the activation of PSs and therefore pivotal to enhance the therapeutic effect. We investigate this mechanism in a series of PS-functionalized scintillating nanotubes where the non-radiative energy transfer yield has been tuned by control of the intermolecular distance between the nanotube and the conjugated system. The obtained results indicate that non-radiative energy transfer has a negligible effect on the ROS sensitization efficiency, thus opening the way to the development of different architectures for breakthrough radiotherapy coadjutants to be tested in clinics.

Photo- and radio-luminescence of porphyrin functionalized ZnO/SiO2 nanoparticles.

The development of hybrid nanoscintillators is hunted for the implementation of modern detection technologies, like in high energy physics, homeland security, radioactive gas sensing, and medical imaging, as well as of the established therapies in radiation oncology, such as in X-ray activated photodynamic therapy. Engineering of the physico-chemical properties of nanoparticles (NPs) enables the manufacture of hybrids in which the conjugation of inorganic/organic components leads to increased multifunctionality and performance. However, the optimization of the properties of nanoparticles in combination with the use of ionizing radiation is not trivial: a complete knowledge on the structure, composition, physico-chemical features, and scintillation property relationships in hybrid nanomaterials is pivotal for any applications exploiting X-rays. In this paper, the design of hybrid nanoscintillators based on ZnO grown onto porous SiO2 substrates (ZnO/SiO2) has been performed in the view to create nanosystems potentially suitable in X-ray activated photodynamic therapy. Indeed, cytotoxic porphyrin dyes with increasing concentrations have been anchored on ZnO/SiO2 nanoparticles through amino-silane moieties. Chemical and structural analyses correlated with photoluminescence reveal that radiative energy transfer between ZnO and porphyrins is the principal mechanism prompting the excitation of photosensitizers. The use of soft X-ray excitation results in a further sensitization of the porphyrin emission, due to augmented energy deposition promoted by ZnO in the surroundings of the chemically bound porphyrin. This finding unveils the cruciality of the design of hybrid nanoparticles in ruling the efficacy of the interaction between ionizing radiation and inorganic/organic moieties, and thus of the final nanomaterial performances towards the foreseen application.

Design Principles of Hybrid Nanomaterials for Radiotherapy Enhanced by Photodynamic Therapy.

Radiation (RT) remains the most frequently used treatment against cancer. The main limitation of RT is its lack of specificity for cancer tissues and the limited maximum radiation dose that can be safely delivered without damaging the surrounding healthy tissues. A step forward in the development of better RT is achieved by coupling it with other treatments, such as photodynamic therapy (PDT). PDT is an anti-cancer therapy that relies on the light activation of non-toxic molecules-called photosensitizers-to generate ROS such as singlet oxygen. By conjugating photosensitizers to dense nanoscintillators in hybrid architectures, the PDT could be activated during RT, leading to cell death through an additional pathway with respect to the one activated by RT alone. Therefore, combining RT and PDT can lead to a synergistic enhancement of the overall efficacy of RT. However, the involvement of hybrids in combination with ionizing radiation is not trivial: the comprehension of the relationship among RT, scintillation emission of the nanoscintillator, and therapeutic effects of the locally excited photosensitizers is desirable to optimize the design of the hybrid nanoparticles for improved effects in radio-oncology. Here, we discuss the working principles of the PDT-activated RT methods, pointing out the guidelines for the development of effective coadjutants to be tested in clinics.

The Sensitization of Scintillation in Polymeric Composites Based on Fluorescent Nanocomplexes.

The sensitization of scintillation was investigated in crosslinked polymeric composite materials loaded with luminescent gold clusters aggregates acting as sensitizers, and with organic dye rhodamine 6G as the emitting species. The evolution in time of the excited states population in the systems is described by a set of coupled rate equations, in which steady state solution allowed obtainment of an expression of the sensitization efficacy as a function of the characteristic parameters of the employed luminescent systems. The results obtained indicate that the realization of sensitizer/emitter scintillating complexes is the strategy that must be pursued to maximize the sensitization effect in composite materials.

Combined grade and nuclear grade are prognosis predictors of epithelioid malignant peritoneal mesothelioma: a multi-institutional retrospective study.

Epithelioid mesothelioma is the most prevalent subtype of diffuse malignant peritoneal mesothelioma. A recently described nuclear-grading system predicted survival in patients with epithelioid malignant pleural mesothelioma. The present study was undertaken to validate this grading system in epithelioid malignant peritoneal mesothelioma (EMPM) and to compare to combined grade, including nuclear atypia, mitotic count, and tumor necrosis. Cases of EMPM, from 1995 to 2018, were analyzed from 7 French institutions from RENAPE network. Solid growth, tumor necrosis, nuclear atypia, and mitotic count were evaluated by at least 3 pathologists from the RENAPATH group. The predictions in terms of OS and PFS of nuclear grade and combined grade were analyzed. Nuclear grade was computed combining nuclear atypia score and mitotic count into a grade of I-III. Another system combining nuclear atypia score, mitotic score, and tumor necrosis was evaluated and defined as a combined grade I-III. A total of 138 cases were identified. The median follow-up was 38.9 months (range: 1.1-196.6). Nuclear and combined grades III were independently associated with a shorter OS (p < 0.05), and a shorter PFS (p < 0.05). Patients with combined grade I tumors had the best overall and progression-free survivals, in comparison to nuclear grade I. In this large multicentric study, combined grade and nuclear grade were the best independent predictors of OS and PFS in EMPM. These systems should be easily described by pathologists involved into the management of malignant peritoneal mesothelioma, because of their potential therapeutic implications.

Tertiary lymphoid structures in epithelioid malignant peritoneal mesothelioma are associated with neoadjuvant chemotherapy, but not with prognosis.

Epithelioid mesothelioma is the most prevalent subtype of diffuse malignant peritoneal mesothelioma. The relationship between a strong adaptive immune response and a better prognosis in malignant solid tumors is widely known. Due to the low incidence of epithelioid malignant peritoneal mesothelioma (EMPM), very little is known about their immune micro-environment. We encountered several cases of tertiary lymphoid structures in EMPM in a previous study and aimed to investigate in the same series the prevalence, clinicopathological features, and the prognostic impact associated with tertiary lymphoid structures in EMPM (TLS-EMPM). Cases of EMPM, from 1995 to 2018, were retrieved from 7 French institutions from the RENAPE Network. The predictions in terms of overall survival (OS) and progression-free survival (PFS) of TLS-EMPM were analyzed. We report 52 cases of TLS-EMPM among a series of 138 cases of EMPM. TLS-EMPM was significantly associated with neoadjuvant chemotherapy, and was not a prognostic indicator for OS (p = 0.652) and PFS (p = 0.804) in our series. TLS is a component of the host immune response to EMPM significantly associated with neoadjuvant chemotherapy, but was not a predictor of prognosis for overall and progression-free survivals in this series. These findings provide another possible etiology for tertiary lymphoid structures.

Functionalized Scintillating Nanotubes for Simultaneous Radio- and Photodynamic Therapy of Cancer.

As a model radio-photodynamic therapy (RPDT) agent, we developed a multicomponent nanomaterial by anchoring conjugated chromophores on the surface of scintillating chrysotile nanotubes. Its ultimate composition makes the system a scintillation-activated photosensitizer for the singlet oxygen production. This nanomaterial shows a remarkable ability to enhance the production of singlet oxygen in an aqueous environment, under X-ray irradiation, boosting its production by almost 1 order of magnitude. Its efficiency as a coadjutant for radiotherapy has been tested in vitro, showing a striking efficacy in enhancing both the prompt cytotoxicity of the ionizing radiation and the long-term cytotoxicity given by radiation-activated apoptosis. Notably, the beneficial activity of the RPDT agent is prominent at low levels of delivered doses comparable to the one employed in clinical treatments. This opens the possibility of effectively reducing the therapy exposure and consequently undesired collateral effects due to prolonged exposure of patients to high-energy radiation.

Morphology Related Defectiveness in ZnO Luminescence: From Bulk to Nano-Size.

This study addresses the relationship between material morphology (size, growth parameters and interfaces) and optical emissions in ZnO through an experimental approach, including the effect of different material dimensions from bulk to nano-size, and different excitations, from optical sources to ionizing radiation. Silica supported ZnO nanoparticles and ligand capped ZnO nanoparticles are synthesized through a sol-gel process and hot injection method, respectively. Their optical properties are investigated by radioluminescence, steady-state and time-resolved photoluminescence, and compared to those of commercial micrometric powders and of a bulk single crystal. The Gaussian spectral reconstruction of all emission spectra highlights the occurrence of the same emission bands for all samples, comprising one ultraviolet excitonic peak and four visible defect-related components, whose relative intensities and time dynamics vary with the material parameters and the measurement conditions. The results demonstrate that a wide range of color outputs can be obtained by tuning synthesis conditions and size of pure ZnO nanoparticles, with favorable consequences for the engineering of optical devices based on this material.

Efficient, fast and reabsorption-free perovskite nanocrystal-based sensitized plastic scintillators.

The urgency for affordable and reliable detectors for ionizing radiation in medical diagnostics, nuclear control and particle physics is generating growing demand for scintillator devices combining efficient scintillation, fast emission lifetime, high interaction probability with ionizing radiation and mitigated reabsorption losses in large-volume/high-density detectors. To date, the simultaneous achievement of all such features is still an open challenge. Here we realize this regime with poly(methyl methacrylate) nanocomposites embedding CsPbBr3 perovskite nanocrystals as sensitizers for a conjugated organic dye featuring a large Stokes shift and a fast emission lifetime in the red spectral region. Complete energy transfer from the nanocrystals to the dye under both X-rays and α-particle excitation results in highly stable radioluminescence with an efficiency comparable to that of commercial-grade inorganic and plastic scintillators; an ~3.4 ns emission lifetime, competitive with fast lanthanide scintillators; and reabsorption-free waveguiding for long optical distances.

Demonstration of cellular imaging by using luminescent and anti-cytotoxic europium-doped hafnia nanocrystals.

Luminescent nanoparticles are researched for their potential impact in medical science, but no materials approved for parenteral use have been available so far. To overcome this issue, we demonstrate that Eu3+-doped hafnium dioxide nanocrystals can be used as non-toxic, highly stable probes for cellular optical imaging and as radiosensitive materials for clinical treatment. Furthermore, viability and biocompatibility tests on artificially stressed cell cultures reveal their ability to buffer reactive oxygen species, proposing an anti-cytotoxic feature interesting for biomedical applications.

Daily Biopsy Diagnosis in Surgical Pathology: Concordance Between Light Microscopy and Whole-Slide Imaging in Real-Life Conditions.

OBJECTIVES: The current challenge for the various digital whole-slide imaging (WSI) systems is to be definitively validated for diagnostic purposes. We designed a concordance study between glass slide and digital slide diagnosis in real-life conditions, coupled with an ergonomic study. METHODS: Three senior pathologists evaluated, first in glass slides and then in digital slides, 119 biopsy cases, including 749 slides, with 332 H&E saffron stains and 417 additional techniques, mainly immunohistochemistry. RESULTS: All digital slides, including specially stained slides, were interpretable. Concordance between glass slides and digital slides was observed in 87.4% of cases. Minor discordances were observed in 12 (10.1%) cases and major discordances, with therapeutic impact, in three (2.5%), including one related to WSI. The satisfaction of participants was high and increased with time. CONCLUSIONS: Our study confirms the feasibility and accuracy of WSI diagnosis, even for cases having multiple samples and requiring special staining techniques, such as immunohistochemistry and in situ hybridization.

Dual inhibition using cabozantinib overcomes HGF/MET signaling mediated resistance to pan-VEGFR inhibition in orthotopic and metastatic neuroblastoma tumors.

MET is expressed on neuroblastoma cells and may trigger tumor growth, neoangiogenesis and metastasis. MET upregulation further represents an escape mechanism to various anticancer treatments including VEGF signaling inhibitors. We developed in vitro a resistance model to pan-VEGFR inhibition and explored the simultaneous inhibition of VEGFR and MET in neuroblastoma models in vitro and in vivo using cabozantinib, an inhibitor of the tyrosine kinases including VEGFR2, MET, AXL and RET. Resistance in IGR-N91-Luc neuroblastoma cells under continuous in vitro exposure pressure to VEGFR1-3 inhibition using axitinib was associated with HGF and p-ERK overexpression. Cabozantinib exhibited anti-proliferative effects in neuroblastoma cells and reduced cell migration in vitro as measured by phase-contrast with IncuCyte system. In vivo, an enhanced number of animals with IGR-N91-Luc metastases was noted following axitinib treatment as compared to control animals. Orally administered cabozantinib per gavage at 30 and 60 mg/kg/day significantly inhibited tumor growth of orthotopic adrenal IGR-N91-Luc and metastatic IMR-32-Luc xenografts. Antitumor activity was associated with decreased vascularization, inhibition of p-SRC and induction of apoptotic cell death. Activation of the HGF-mediated MET pathway is involved in escape to selective VEGFR inhibition in neuroblastoma suggesting combined inhibition of MET and VEGFR signaling to reduce secondary resistance and enhanced invasiveness.

Análisis del estado nutricional y composición corporal de personas con discapacidad intelectual / Analysis of the nutritional status and body composition of persons with intellectual disability

Introducción. La discapacidad intelectual, definida como limitaciones sustanciales en el funcionamiento intelectual, afecta al 0,7-1,5% de la población. Estas personas presentan mayores tasas de obesidad, y sus valores calóricos y estado nutricional son deficientes. Objetivos. Conocer los hábitos nutricionales, analizar la eficacia de la educación nutricional y evaluar la posible mejora, introduciendo talleres de ejercicio físico y nutrición, en la discapacidad intelectual. Pacientes y métodos. Se realizó una valoración clínica, nutricional y antropométrica (peso, talla, índice de masa corporal, grasa corporal, perímetro de la cintura) a 47 sujetos con discapacidad intelectual. Se registraron los hábitos deportivos, la historia clínica y la historia dietética mediante un registro alimentario y un cuestionario de adhesión a la dieta mediterránea (KidMed). Los talleres de nutrición y ejercicio físico contaron con una estructura de explicación teórica, práctica y juegos. Resultados. El 76,1% presentaba exceso ponderal en el inicio del estudio. Tras la intervención, los valores de grasa corporal (-0,94 ± 4,4%) y grasa visceral (-0,86 ± 2%), así como el peso (-0,4 ± 3,3 kg) y el índice de masa corporal (-0,2 ± 1,6 kg/m2), disminuyeron, más en las mujeres que en los hombres. El 60,5% no cumplía con una alta adhesión a la dieta mediterránea. Tras la intervención, se observó una diferencia significativa (p ≤ 0,001) en la puntuación del KidMed. El taller de actividad física tuvo efectos positivos sobre la antropometría. Conclusiones. La alimentación fue inadecuada en la mayoría de los individuos. La prevalencia de obesidad fue elevada. Los talleres de educación nutricional y de ejercicio son una herramienta útil para trabajar con este colectivo, y consiguen cambios significativos para prevenir la obesidad y mejorar su salud (AU)

Introduction. Intellectual disability refers to substantial limitations in intellectual functioning, affecting 0.7-1.5% of the population. People with intellectual disability have higher rates of obesity, since caloric values and nutritional status, are deficient. Aims. To determine the nutritional habits, analyze the effectiveness of nutritional education and evaluate the possible effect of improvement introducing exercise and nutrition workshops, in a group of people with intellectual disability. Patients and methods. Clinical, nutritional and anthropometric (weight, height, body mass index, body fat, waist circumference) assessment was conducted in 47 patients. An ad hoc survey was designed in which exercise habits, medical and dietary history, record of 72 hours (including 2 weekdays and 1 weekend) and the adherence to Mediterranean diet data were collected. The workshops of exercise and nutrition counted with a structure of theoretical-practical explanation and games. Results. 76.1% presented weight excess at baseline. After the intervention values of total body fat (-0.94 ± 4.4%) and visceral fat (-0.86 ± 2%), weight (-0.4 ± 3.3 kg) and body mass index (-0.2 ± 1.6 kg/m2) decreased, more in women than in men. 60.5% of subjects did not meet a high adherence to the Mediterranean diet. After nutritional intervention, a significant difference (p ≤ 0,001) was observed in the KidMed score. The workshop of physical activity had positive effects on the anthropometry of subjects. Conclusions. Both the intake and the prevalence of obesity in this group of people are inadequate. Nutritional education and physical exercise workshops are useful for working with this group, achieving significant changes to prevent obesity and improve their health (AU)

In vivo autofluorescence in the biological windows: the role of pigmentation.

Small animal deep-tissue fluorescence imaging in the second Biological Window (II-BW, 1000-1350 nm) is limited by the presence of undesirable infrared-excited, infrared-emitted (900-1700 nm) autofluorescence whose origin, spectral properties and dependence on strains is still unknown. In this work, the infrared autofluorescence and laser-induced whole body heating of five different mouse strains with distinct coat colors (black, grey, agouti, white and nude) has been systematically investigated. While neither the spectral properties nor the magnitude of organ autofluorescence vary significantly between mouse strains, the coat color has been found to strongly determine both the autofluorescence intensity as well as the laser-induced whole body heating. Results included in this work reveal mouse strain as a critical parameter that has to be seriously considered in the design and performance of small animal imaging experiments based on infrared-emitting fluorescent markers.

Regorafenib: Antitumor Activity upon Mono and Combination Therapy in Preclinical Pediatric Malignancy Models.

The multikinase inhibitor regorafenib (BAY 73-4506) exerts both anti-angiogenic and anti-tumorigenic activity in adult solid malignancies mainly advanced colorectal cancer and gastrointestinal stromal tumors. We intended to explore preclinically the potential of regorafenib against solid pediatric malignancies alone and in combination with anticancer agents to guide the pediatric development plan. In vitro effects on cell proliferation were screened against 33 solid tumor cell lines of the Innovative Therapies for Children with Cancer (ITCC) panel covering five pediatric solid malignancies. Regorafenib inhibited cell proliferation with a mean half maximal growth inhibition of 12.5 µmol/L (range 0.7 µmol/L to 28 µmol/L). In vivo, regorafenib was evaluated alone at 10 or 30 mg/kg/d or in combination with radiation, irinotecan or the mitogen-activated protein kinase kinase (MEK) inhibitor refametinib against various tumor types, including patient-derived brain tumor models with an amplified platelet-derived growth factor receptor A (PDGFRA) gene. Regorafenib alone significantly inhibited tumor growth in all xenografts derived from nervous system and connective tissue tumors. Enhanced effects were observed when regorafenib was combined with irradiation and irinotecan against PDGFRA amplified IGRG93 glioma and IGRM57 medulloblastoma respectively, resulting in 100% tumor regressions. Antitumor activity was associated with decreased tumor vascularization, inhibition of PDGFR signaling, and induction of apoptotic cell death. Our work demonstrates that regorafenib exhibits significant antitumor activity in a wide spectrum of preclinical pediatric models through inhibition of angiogenesis and induction of apoptosis. Furthermore, radio- and chemosensitizing effects were observed with DNA damaging agents in PDGFR amplified tumors.

Negative prognostic impact of regulatory T cell infiltration in surgically resected esophageal cancer post-radiochemotherapy.

Ever accumulating evidence indicates that the long-term effects of radiotherapy and chemotherapy largely depend on the induction (or restoration) of an anticancer immune response. Here, we investigated this paradigm in the context of esophageal carcinomas treated by neo-adjuvant radiochemotherapy, in a cohort encompassing 196 patients. We found that the density of the FOXP3+ regulatory T cell (Treg) infiltrate present in the residual tumor (or its scar) correlated with the pathological response (the less Tregs the more pronounced was the histological response) and predicted cancer-specific survival. In contrast, there was no significant clinical impact of the frequency of CD8+ cytotoxic T cells. At difference with breast or colorectal cancer, a loss-of-function allele of toll like receptor 4 (TLR4) improved cancer-specific survival of patients with esophageal cancer. While a loss-of-function allele of purinergic receptor P2X, ligand-gated ion channel, 7 (P2RX7) failed to affect cancer-specific survival, its presence did correlate with an increase in Treg infiltration. Altogether, these results corroborate the notion that the immunosurveillance seals the fate of patients with esophageal carcinomas treated with conventional radiochemotherapy.

Constitutively altered frequencies of circulating follicullar helper T cell counterparts and their subsets in rheumatoid arthritis.

INTRODUCTION: Circulating CD4 T cells expressing CXCR5, ICOS and/or PD-1 are counterparts of follicular helper T cells (Tfh). There are three subpopulations of circulating Tfh (cTfh): CXCR5 + CXCR3 + CCR6- (Tfh-Th1), CXCR5 + CXCR3-CCR6- (Tfh-Th2) and CXCR5 + CXCR3-CCR6+ (Tfh-Th17). Our objective was to study the B cell helping capacity of cTfh subsets, and examine their frequency in Rheumatoid Arthritis (RA) patients, together with the frequency of circulating plasmablasts (CD19 + CD20-CD38high). METHODS: Peripheral blood was drawn from RA patients with active disease (RA-a, DAS28 >2.6) (n = 17), RA in remission (RA-r, DAS28 <2.6) (n = 17) and healthy controls (HC) (n = 34). cTfh and plasmablast frequencies were determined by flow cytometry. Cocultures of sorted CD4 + CXCR5+ T cell subpopulations were established with autologous CD19 + CD27- naïve B cells of HC, and concentrations of IgG, A and M were measured in supernatants. RESULTS: Isolated Tfh-Th2 and Tfh-Th17 but not Tfh-Th1 cells, induced naïve B cells to secrete IgG and IgA. The frequency of CXCR5+ cells gated for CD4+ T cells was not different among HC, RA-a and RA-r. In contrast, both RA-a and RA-r patients demonstrated an increased frequency of CD4 + CXCR5 + ICOS+ T cells and augmented (%Tfh-Th2 + %Tfh-Th17)/%Tfh-Th1 ratio as compared with HC. In addition, RA-a but not RA-r patients, showed an increased frequency of circulating plasmablasts. CONCLUSION: Both RA-a and RA-r patients demonstrate an increased frequency of cTfh and overrepresentation of cTfh subsets bearing a B cell helper phenotype, suggesting that altered germinal center dynamics play a role in RA pathogenesis. In contrast, only RA-a patients show an increased proportion of circulating plasmablasts.

Decreased frequencies of circulating follicular helper T cell counterparts and plasmablasts in ankylosing spondylitis patients Naïve for TNF blockers.

Follicular helper T cells (Tfh), localized in lymphoid organs, promote B cell differentiation and function. Circulating CD4 T cells expressing CXCR5, ICOS and/or PD-1 are counterparts of Tfh. Three subpopulations of circulating CD4+CXCR5+ cells have been described: CXCR3+CCR6- (Tfh-Th1), CXCR3-CCR6+ (Tfh-Th17), and CXCR3-CCR6- (Tfh-Th2). Only Tfh-Th17 and Tfh-Th2 function as B cell helpers. Our objective was to study the frequencies of circulating Tfh (cTfh), cTfh subsets and plasmablasts (CD19+CD20-CD27+CD38high cells), and the function of cTfh cells, in patients with Ankylosing Spondylitis (AS). To this end, peripheral blood was drawn from healthy controls (HC) (n = 50), AS patients naïve for TNF blockers (AS/nb) (n = 25) and AS patients treated with TNF blockers (AS/b) (n = 25). The frequencies of cTfh and plasmablasts were determined by flow cytometry. Cocultures of magnetically sorted CD4+CXCR5+ T cells with autologous CD19+CD27- naïve B cells were established from 3 AS/nb patients and 3 HC, and concentrations of IgG, A and M were measured in supernatants. We obseved that AS/nb but not AS/b patients, demonstrated decreased frequencies of circulating CD4+CXCR5+ICOS+PD-1+ cells and plasmablasts, together with a decreased (Tfh-Th17+Tfh-Th2)/Tfh-Th1 ratio. The amounts of IgG and IgA produced in cocultures of CD4+CXCR5+ T cells with CD19+CD27- B cells of AS/nb patients were significantly lower than observed in cocultures established from HC. In summary, AS/nb but not AS/b patients, demonstrate a decreased frequency of cTfh and plasmablasts, and an underrepresentation of cTfh subsets bearing a B helper phenotype. In addition, peripheral blood CD4+CXCR5+ T cells of AS/nb patients showed a decreased capacity to help B cells ex vivo.