We have shown that nanoparticles (NPs) can be used as ligand-multimerization platforms to activate specific cellular receptors in vivo. Nanoparticles coated with autoimmune disease-relevant peptide-major histocompatibility complexes (pMHC) blunted autoimmune responses by triggering the differentiation and expansion of antigen-specific regulatory T cells in vivo. Here, we define the engineering principles impacting biological activity, detail a synthesis process yielding safe and stable compounds, and visualize how these nanomedicines interact with cognate T cells. We find that the triggering properties of pMHC-NPs are a function of pMHC intermolecular distance and involve the sustained assembly of large antigen receptor microclusters on murine and human cognate T cells. These compounds show no off-target toxicity in zebrafish embryos, do not cause haematological, biochemical or histological abnormalities, and are rapidly captured by phagocytes or processed by the hepatobiliary system. This work lays the groundwork for the design of ligand-based NP formulations to re-program in vivo cellular responses using nanotechnology.

Background: Toxic epidermal necrolysis (TEN) is a rare severe acute exfoliative drug-induced skin disorder which has recently been ascribed to alterations in the control of keratinocyte apoptosis, mediated by an interaction between the cell surface death receptor Fas and its respective ligand. A therapeutic approach with intravenous immunoglobulins (IVIG) associated with pulse methylprednisolone, based on the inhibition of Fas-mediated keratinocyte death by naturally occurring Fas-blocking antibodies included in human immunoglobulin preparations, has produced good preliminary results. Objective: To analyse the efficacy of IVIG in the treatment of TEN. Patients: Nine patients with erythematous body surface area ranging from 38 to 85% and dermo-epidermal detachment from 4 to 37% were treated. Results: Eight patients were healed and 1 died of septic shock and multiple organ failure. Interruption of further epidermal detachment occurred after an average of 4.8 days from the onset of IVIG therapy. Complete wound healing occurred after an average of 12 days. Concerning complications, 3 out of 8 surviving patients had acute respiratory failure requiring mechanical ventilation and 1 acute renal failure was treated with dialysis. Late sequelae were limited to dyschromia and nail dystrophies. No hypertrophic scars were observed. Conclusion: IVIG therapy represents a safe and valid approach for TEN.

Germinal center follicular T helper (GCTfh) cells are essential players in the differentiation of B cells. Circulating follicular T helper (cTfh) cells share phenotypic and functional properties with GCTfh cells. Distinct subpopulations of cTfh with different helper capabilities toward B cells can be identified: cTfh1 (CXCR3+CCR6−), cTfh2 (CXCR3−CCR6−), and cTfh17 (CXCR3−CCR6+). Alterations in cTfh function and/or distribution have been associated with autoimmunity, infectious diseases, and more recently, with several monogenic immunodeficiencies. Common variable immunodeficiency (CVID) disease is the commonest symptomatic primary immunodeficiency with a genetic cause identified in only 2–10% of patients. Although a heterogeneous disease, most patients show a characteristic defective B cell differentiation into memory B cells or antibody-secreting cells. We investigated if alterations in CVID cTfh cells frequency or distribution into cTfh1, cTfh2, and cTfh17 subpopulations and regulatory follicular T (Tfr) cells could be related to defects in CVID B cells. We found increased percentages of cTfh exhibiting higher programmed death-1 expression and altered subpopulations distribution in smB− CVID patients. In contrast to smB+ patients and controls, cTfh from smB− CVID patients show increased cTfh1 and decreased cTfh17 subpopulation percentages and increased CXCR3+CCR6+ cTfh, a population analogous to the recently described pathogenic Th17.1. Moreover, Tfr cells are remarkably decreased only in smB− CVID patients. In conclusion, increased cTfh17.1 and cTfh1/cTfh17 ratio in CVID patients could influence B cell fate in smB− CVID patients, with a more compromised B cell compartment, and the decrease in Tfr cells may lead to high risk of autoimmune conditions in CVID patients.

No abstract

No abstract

Sixteen Pythium isolates from diverse hosts and locations, which showed similarities in their morphology and sequences of the internal transcribed spacer (ITS) region of their rRNA gene, were investigated. As opposed to the generally accepted view, within single isolates ITS sequence variations were consistently found mostly as part of a tract of identical bases (A-T) within ITS1, and of GT or GTTT repeats within the ITS2 sequence. Thirty-one different ITS sequences obtained from 39 cloned ITS products from the 16 isolates showed high sequence and length polymorphisms within and between isolates. However, in a phylogenetic analysis, they formed a cluster distinct from those of other Pythium species. Additional sequencing of two nuclear genes (elongation factor 1 alpha and beta-tubulin) and one mitochondrial gene (nadh1) revealed high levels of heterozygosity as well as polymorphism within and between isolates, with some isolates possessing two or more alleles for each of the nuclear genes. In contrast to the observed variation in the ITS and other gene areas, all isolates were phenotypically similar. Pythium mercuriale sp. nov. (Pythiaceae) is characterized by forming thin-walled chlamydospores, subglobose to obovoid, papillate sporangia proliferating internally and smooth-walled oogonia surrounded by multiple antheridia. Maximum likelihood phylogenetic analyses based on both ITS and beta-tubulin sequence data place P. mercuriale in a clade between Pythium and Phytophthora.

Objective: Cases of narcolepsy in association with psychotic features have been reported but never fully characterized. These patients present diagnostic and treatment challenges and may shed new light on immune associations in schizophrenia. Method: Our case series was gathered at two narcolepsy specialty centers over a 9-year period. A questionnaire was created to improve diagnosis of schizophrenia or another psychotic disorder in patients with narcolepsy. Pathophysiological investigations included full HLA Class I and II typing, testing for known systemic and intracellular/synaptic neuronal antibodies, recently described neuronal surface antibodies, and immunocytochemistry on brain sections to detect new antigens. Results: Ten cases were identifi ed, one with schizoaffective disorder, one with delusional disorder, two with schizophreniform disorder, and 6 with schizophrenia. In all cases, narcolepsy manifested fi rst in childhood or adolescence, followed by psychotic symptoms after a variable interval. These patients had auditory hallucinations, which was the most differentiating clinical feature in comparison to narcolepsy patients without psychosis. Narcolepsy therapy may have played a role in triggering psychotic symptoms but these did not reverse with changes in narcolepsy medications. Response to antipsychotic treatment was variable. Pathophysiological studies did not reveal any known autoantibodies or unusual brain immunostaining pattern. No strong HLA association outside of HLA DQB1*06:02 was found, although increased DRB3*03 and DPA1*02:01 was notable. Conclusion: Narcolepsy can occur in association with schizophrenia, with signifi cant diagnostic and therapeutic challenges. Dual cases maybe under diagnosed, as onset is unusually early, often in childhood. Narcolepsy and psychosis may share an autoimmune pathology; thus, further investigations in larger samples are warranted. Keywords: type 1 narcolepsy, psychotic disorders, HLA, brain autoantibodies, autoimmune Citation: Canellas F, Lin L, Julià MR, Clemente A, VivesBauza C, Ollila HM, Hong SC, Arboleya SM, Einen MA, Faraco J, Fernandez-Vina M, Mignot E. Dual cases of type 1 narcolepsy with schizophrenia and other psychotic disorders. J Clin Sleep Med 2014;10(9):1011-1018. S C I E N T I F I C I N V E S T I G A T I O N ST ype 1 narcolepsy is a disabling sleep disorder caused by hypocretin-1 defi ciency affecting approximately 0.02% of adults worldwide.1 It is strongly associated with the DQB1*06:02 allele of the human leucocyte antigen (HLA) system, 2 and is likely due to an autoimmune attack causing a specifi c loss of hypothalamic hypocretin-1 neurons.Narcolepsy is characterized by the presence of daytime sleepiness, cataplectic attacks, hypnagogic/hypnopompic hallucinations, sleep paralysis, and disturbed nocturnal sleep. Initially narcolepsy was considered a psychiatric disorder, as some symptoms are reminiscent of psychiatric disorders, for instance, disordered thinking and confusion-like behaviors due to sleepiness; and psychotic-like symptoms d...

No abstract