Asthma and Hypogammaglobulinemia: an Asthma Phenotype with Low Type 2 Inflammation

Purpose

Little is known about hypogammaglobulinemia (HGG) in asthma patients. No data are available on the characteristics of adult patients with asthma and HGG.

Methods

We conducted a retrospective monocentric study between January 2006 and December 2012. Asthma patients with a serum immunoglobulin (Ig) quantitative analysis were included and classified into two groups depending on their serum IgG concentration: presence or absence of HGG. Clinical, biological, functional, and radiologic characteristics were compared in univariate and multivariate analysis, using a logistic regression model.

Results

In univariate analysis, asthma patients with HGG (n?=?25) were older (58 years old?±?18 vs 49?±?18, p?=?0.04) and more frequently active or former smokers as compared to patients with normoglobulinemia (n?=?80) (56.0 vs 35.0 %, p?=?0.01). Total IgE?<?30 kUI/L was more frequently observed in patients with HGG (53.0 vs 18.3 %, p?=?0.01). HGG asthma patients had lower fraction of exhaled nitric oxide (p?=?0.02), blood eosinophilia (p?=?0.0009), and presented with more severe composite score for bronchiectasis (p?=?0.01). In multivariate analysis, asthma patients with HGG had increased risk of being smokers [OR?=?6.11 (IC 95 %?=?1.16–32.04)], having total IgE concentration?<?30 kUI/L [OR?=?12.87 (IC 95 %?=?2.30–72.15)], and a more severe composite score of bronchiectasis [OR?=?20.65 (IC 95 %?=?2.13–199.74)].

Conclusion

Asthma patients with HGG are older and more often tobacco smoker than asthma patients without HGG. These patients have low type-2 inflammation markers.

     

Free-breathing 3D diffusion MRI for high-resolution hepatic metastasis characterization in small animals

The goal of this study was to develop a 3D diffusion weighted sequence for free breathing liver imaging in small animals at high magnetic field. Hepatic metastases were detected and the apparent diffusion coefficients (ADC) were measured. A 3D SE-EPI sequence was developed by (i) inserting a water-selective excitation radiofrequency pulse to suppress adipose tissue signal and (ii) bipolar diffusion gradients to decrease the sensitivity to respiration motion. Mice with hepatic metastases were imaged at 7T by applying b values from 200 to 1100 s/mm². 3D images with high spatial resolution (182 × 156 × 125 µm) were obtained in only 8 min 32 s. The modified DW-SE-EPI sequence allowed to obtain 3D abdominal images of healthy mice with fat SNR 2.5 times lower than without any fat suppression method and sharpness 2.8 times higher than on respiration-triggered images. Due to the high spatial resolution, the core and the periphery of disseminated hepatic metastases were differentiated at high b-values only, demonstrating the presence of edema and proliferating cells (with ADC of 2.65 × 10^?3 and 1.55 × 10^?3 mm²/s, respectively). Furthermore, these metastases were accurately distinguished from proliferating ones within the same animal at high b-values (mean ADC of 0.38 × 10^?3 mm²/s). Metastases of less than 1.7 mm³ diameter were detected. The new 3D SE-EPI sequence enabled to obtain diffusion information within liver metastases. In addition of intra-metastasis heterogeneity, differences in diffusion were measured between metastases within an animal. This sequence could be used to obtain diffusion information at high magnetic field.     

Altered B lymphocyte homeostasis and functions in systemic sclerosis

Beyond the production of autoantibodies, B-cells are thought to play a role in systemic sclerosis (SSc) by secreting proinflammatory/profibrotic cytokines. B-cells are a heterogeneous population with different subsets distinguished by their phenotypes and cytokine production. Data about B-cell subsets, cytokine production and intracellular pathways leading to this production are scarce in SSc. The aim of our study was to describe B-cell homeostasis, activation, proliferation, cytokine production in B-cells and serum and B-cell intracellular signaling pathways in SSc. We hypothezided that B-cell homeostasis and cytokine production were altered in SSc and could be explained by serum cytokine as well as by intracellular signaling pathway abnormalities.Forty SSc patients and 20 healthy controls (HC) were prospectively included. B-cell subsets were determined by flow cytometry using CD19, CD21, CD24, CD38, CD27, IgM and IgD. CD25, CD80, CD95, HLA-DR were used to assess B-cell activation. Intracellular production of IL-10 and IL-6 were assessed by flow cytometry after TLR9 and CD40 stimulation. IL-6, IL-10, Ki67, Bcl2 mRNA were quantified in B-cells. Cytokine production was also assessed in sera and supernatants of B-cell culture, using a multiplex approach. Signaling pathways were studied through phosphorylation of mTOR, ERK, STAT3, STAT5 using a flow cytometry approach.We found that SSc patients exhibited an altered peripheral blood B-cell subset distribution, with decreased memory B-cells but increased proportion of naive and CD21^LoCD38^Lo B-cell subsets. We observed an increased expression of activation markers (CD80, CD95, HLA-DR) on some B-cell subsets, mainly the memory B-cells. Secretion of IL-6, BAFF and CXCL13 were increased in SSc sera. There was no correlation between the peripheral blood B-cell subsets and the serum concentrations of these cytokines. After stimulation, we observed a lower proportion of IL-10 and IL-6 producing B–cells in SSc. Finally, we observed a significant decrease of mTOR phosphorylation in SSc patient B-cells.In conclusion, we observed an altered B-cell homeostasis in SSc patients compared to HC. Memory B-cells were both decreased and activated in patients. IL-10 producing B-cells were decreased in SSc. This decrease was associated with an alteration of mTOR phosphorylation in B-cells. Conversely, there was no correlation between serum cytokine profile and B-cell homeostasis alterations.     

Genetic Variations and Diseases in UniProtKB/Swiss‐Prot: The Ins and Outs of Expert Manual Curation

During the last few years, next‐generation sequencing (NGS) technologies have accelerated the detection of genetic variants resulting in the rapid discovery of new disease‐associated genes. However, the wealth of variation data made available by NGS alone is not sufficient to understand the mechanisms underlying disease pathogenesis and manifestation. Multidisciplinary approaches combining sequence and clinical data with prior biological knowledge are needed to unravel the role of genetic variants in human health and disease. In this context, it is crucial that these data are linked, organized, and made readily available through reliable online resources. The Swiss‐Prot section of the Universal Protein Knowledgebase (UniProtKB/Swiss‐Prot) provides the scientific community with a collection of information on protein functions, interactions, biological pathways, as well as human genetic diseases and variants, all manually reviewed by experts. In this article, we present an overview of the information content of UniProtKB/Swiss‐Prot to show how this knowledgebase can support researchers in the elucidation of the mechanisms leading from a molecular defect to a disease phenotype.     

Effect of mild cognitive impairment on the patterns of neural activity in early Parkinson's disease

We have previously observed decreased activation of corticostriatal loops involved in planning (cognitive loop) and execution (motor loop) of a set shift in patients with early Parkinson's disease (PD) compared with control subjects. Here, we aimed to assess whether cognitive impairment in PD could drive these differences. Nondemented patients underwent a comprehensive neuropsychological evaluation and participated in our Wisconsin Card Sorting task functional magnetic resonance imaging protocol. Patients were separated into 2 groups according to the presence of mild cognitive impairment (MCI). Patients with MCI displayed reduced activity in the cognitive corticostriatal loop, which includes the caudate nucleus and prefrontal cortex while planning a set shift, whereas non-MCI patients exhibited activation patterns similar to those of healthy participants from our previous studies. Furthermore, reduced activation was observed in the premotor cortex of the MCI patients. Finally, hippocampal activity, correlated with individual memory scores, suggesting a compensatory mechanism in patients with preserved memory. These results suggest that the presence of MCI in PD affects activity in the prefrontal cortex and caudate nucleus as well as motor-related regions.     

Mutations in SYNGAP1 Cause Intellectual Disability,Autism, and a Specific Form of Epilepsy by Inducing Haploinsufficiency

De novo mutations in SYNGAP1, which codes for a RAS/RAP GTP‐activating protein, cause nonsyndromic intellectual disability (NSID). All disease‐causing point mutations identified until now in SYNGAP1 are truncating, raising the possibility of an association between this type of mutations and NSID. Here, we report the identification of the first pathogenic missense mutations (c.1084T>C [p.W362R], c.1685C>T [p.P562L]) and three novel truncating mutations (c.283dupC [p.H95PfsX5], c.2212_2213del [p.S738X], and (c.2184del [p.N729TfsX31]) in SYNGAP1 in patients with NSID. A subset of these patients also showed ataxia, autism, and a specific form of generalized epilepsy that can be refractory to treatment. All of these mutations occurred de novo, except c.283dupC, which was inherited from a father who is a mosaic. Biolistic transfection of wild‐type SYNGAP1 in pyramidal cells from cortical organotypic cultures significantly reduced activity‐dependent phosphorylated extracellular signal‐regulated kinase (pERK) levels. In contrast, constructs expressing p.W362R, p.P562L, or the previously described p.R579X had no significant effect on pERK levels. These experiments suggest that the de novo missense mutations, p.R579X, and possibly all the other truncating mutations in SYNGAP1 result in a loss of its function. Moreover, our study confirms the involvement of SYNGAP1 in autism while providing novel insight into the epileptic manifestations associated with its disruption.     

Differential association of phosphatases with hematopoietic co-receptors bearing immunoreceptor tyrosine-based inhibition motifs

A novel family of inhibitory co-receptors has been recently defined according to the presence in their intracytoplasmic domain of immunoreceptor tyrosine-based inhibition motifs (ITIM). In particular, this family includes a low-affinity receptor for IgG, FcγRIIB, which is widely expressed on hematopoietic cells, as well as killer cell inhibitory receptors (KIR) for major histocompatibility complex (MHC) class I proteins, expressed on both T and natural killer (NK) lymphocytes. FcγRIIB and KIR inhibitory function depends upon the tyrosine phosphorylation of their respective ITIM. Phosphorylated FcγRIIB and KIR ITIM bind the tandem SH2 tyrosine phosphatases, SHP-1 and SHP-2. Recently, FcγRIIB has been shown to associate with a polyphosphate inositol 5-phosphatase, SHIP, which appears to be involved in its inhibitory function. Using cell lysate adsorption to phosphorylated ITIM peptides and surface plasmon resonance, we demonstrate here that, in contrast to FcγRIIB, KIR (CD158b: p58.2) do not bind to SHIP, and only recruit SHP-1 and SHP-2. In addition, we show that point mutation of the amino acid residue in position tyrosine-2 of FcγRIIB and KIR ITIM abolihes their binding to SHP-1 and SHP-2, but leaves intact the association of SHIP with FcγRIIB ITIM. These data contribute to the structural definition of ITIM and document a differential recruitment of phosphatases by distinct ITIM. These findings also reveal that diverse strategies of inhibition are used by distinct members of the ITIM-bearing co-receptor family.     

Evaluation of the polymorphisms associated with tandem repeats for Pseudomonas aeruginosa strain typing

We report on the development of a scheme for the typing of Pseudomonas aeruginosa, multiple-locus variable number of tandem repeat (VNTR) analysis (MLVA). We first evaluated the polymorphisms of 201 tandem repeat loci selected from more than 3,000 such sequences present in strain PAO1 with a test collection of 12 genotypically distinct clinical strains. Seven VNTR loci which can be easily scored with the technology used here were identified and used to genotype a collection of 89 clinical isolates that had previously been classified into 46 ribotypes, including 2 widespread ribotypes. Seventy-one different MLVA genotypes could be distinguished. With only two exceptions, strains with identical ribotypes were grouped together upon cluster analysis of the MLVA data. The 27 isolates with the most frequent ribotype were divided into 14 MLVA types, and the 18 isolates with the second most frequent ribotype were divided into 15 MLVA types. Analysis of a subset of 17 strains belonging to the major ribotype by pulsed-field gel electrophoresis with the enzyme SpeI distinguished seven types, identical to the number of MLVA types in this subset. Our data show that MLVA typing of P. aeruginosa based on the first set of loci has a high discriminatory power. Because MLVA is highly reproducible and easily portable among laboratories, it represents a very promising tool for the molecular surveillance of P. aeruginosa. A free, online strain identification service based on the genotyping data produced herein has been developed.     

Effect of the Penultimate Unit on the C?ON Bond Homolysis in SG1‐Based Alkoxyamines

The effect of the penultimate unit on the C? ON bond homolysis rate constant k_d was studied for model alkoxyamines. It was shown that the k_d for fragments containing penultimate and antepenultimate units were nicely predicted by the tri‐parametric relationship developed in Macromolecules 2005 , 38, 2638 and Eur. J. Org. Chem. 2006 , 7, 1755 (log k_d = ?14.33 + 15.06 × σ_RS + 20.00 × σ_I + 6.96 × υ). A striking effect was observed only for a tert‐butyl‐like group as the penultimate unit.

     

Identification, in mouse macrophages and in serum, of a soluble receptor for the Fc portion of IgG (Fc{gamma}R) encoded by an alternatively spliced transcript of the Fc{gamma}RII gene

Low affinity FcR are a heterogeneous group of glycoproteinswhich exist in transmembrane (TM) as well as in soluble forms.Two membrane isoforms of the murine type II FcR, FcRilb1 andFc;Rilb2, have been described. They result from the translationof alternatively spliced premRNA, FcRilb2 lacking sequencesof the first intracytoplasmic domain (IC1). Soluble forms ofFcR (sFcR) have previously been shown to result from proteolysisof membrane receptors. We report here the identification, inmacrophages, of a mRNA derived from the FCRll gene by splicingexons encoding the TM and IC1 domains, i.e. corresponding toa TM-deleted FcRllb2 mRNA. A soluble protein possibly encodedby this mRNA was identified in macrophage supernatants. In accordancewith FcR nomenclature, we propose to name this new FcRll IsoformFcRllb3. It is the most abundant 8FcR present in serum, as comparedwith 8FcR resulting from cleavage of membrane FcR.