Etat des lieux de la prise en charge de l'infection par le VIH en médecine générale au sein des Pays de la Loire en 2011: (Ressenti des médecins généralistes de la Sarthe et des patients suivis au CHU d'Angers)

ANGERS-BU Médecine-Pharmacie (490072105) / SudocSudocFranceF

Fortuitous diagnosis of NDM-1producing Acinetobacter pittii carriage in a patient from France with no recent history of travel

International audienceNo abstract availabl

Characterization of antigen-specific B cells using nominal antigen-coated flow-beads.

In order to characterize the reactivity of B cells against nominal antigens, a method based on the coupling of antigens onto the surface of fluorescent core polystyrene beads was developed. We first demonstrate that murine B cells with a human MOG-specific BCR are able to interact with MOG-coated beads and do not recognize beads coated with human albumin or pp65. B cells purified from human healthy volunteer blood or immunized individuals were tested for their ability to interact with various nominal antigens, including viral, vaccine, self and alloantigens, chosen for their usefulness in studying a variety of pathological processes. A substantial amount of B cells binding self-antigen MOG-coated beads can be detected in normal blood. Furthermore, greater frequencies of B cell against anti-Tetanic Toxin or anti-EBNA1 were observed in primed individuals. This method can reveal increased frequencies of anti-HLA committed B cells in patients with circulating anti-HLA antibodies compared to unsensitized patients and normal individuals. Of interest, those specific CD19 cells were preferentially identified within CD27(-)IgD(+) (i-e naïve) subset. These observations suggest that a broad range of medical situations could benefit from a tool that allows the detection, the quantification and the characterization of antigen-specific blood B cells

Trimethoprim/sulfamethoxazole for nocardiosis in solid organ transplant recipients: Real-life data from a multicentre retrospective study.

BACKGROUND Little is known regarding the optimal management of nocardiosis among solid organ transplant (SOT) recipients. It is often suggested to avoid trimethoprim/sulfamethoxazole (TMP-SMX) monotherapy in heavily immunocompromised patients (such as SOT recipients) and/or in case of severe or disseminated nocardiosis. Our aim was to report our experience with TMP-SMX monotherapy in SOT recipients with nocardiosis. METHODS Using data from a previously published European study, we assessed the incidence of adverse events in SOT recipients receiving TMP-SMX monotherapy and assessed its effectiveness. RESULTS Thirty-one SOT recipients with nocardiosis were included, mostly kidney transplant recipients (20/31, 65%). Eleven (36%) had disseminated infection, and four (13%) had brain nocardiosis. Most patients had lung and/or pleural involvement (26/31, 84%). Daily dose of trimethoprim at initiation was 10 [6.4-14.8] mg/kg. The median estimated glomerular filtration rate at time of diagnosis of nocardiosis was 44 [30-62] ml/min/1.73 m². TMP-SMX was discontinued prematurely in one third of the patients (10/31, 32%, mostly for hematological toxicity [n = 3] or increased serum creatinine [n = 3]). Focusing on the 24 (77%) patients who completed at least 30 days of TMP-SMX monotherapy, 4 had late (>30 days) drug discontinuation, 1 experienced treatment failure, and 19 completed planned TMP-SMX monotherapy. Clinical outcome was favorable in these 19 patients, despite the fact that 8 (42%) had disseminated infection and 2 (11%) brain nocardiosis. Overall, all-cause 1-year mortality was 10% (3/31). CONCLUSIONS TMP-SMX monotherapy appears to be effective for the treatment of most nocardiosis among SOT recipients. Interventional studies are needed to compare its safety and effectiveness with those of other regimens used to treat posttransplant nocardiosis

Separation of B cells interacting with nominal antigen and unbound B cells.

<p>Purified B cells were incubated with single HLA class I coated beads (A) or MOG_1–125 coated beads (B) before being subjected to cell separation using an ARIA FACS-sorter (A) or magnet based purification (B). Frequency of B cells interacting with nominal antigens is shown before purification and in the positive and in the negative fraction. One representative out of three experiments with cells from different donors is shown.</p

Principle of the method of identification of antigen-specific B cells.

<p>After co-incubation, lymphocytes, antigen covered beads and the beads’ B cell rosettes are gated based on their forward scatter and side scatter. After exclusion of the DAPI+ cells, B cells and beads-B cell rosettes are identified based on CD19 expression and the beads’ internal fluorochrome. Specificity of B cell recognition is determined by gating on beads and beads’ B cell rosettes (<b>A</b>) or after the identification of the nominal antigen through the use of the unique ratio of the two internal fluorochromes (<b>B</b>). In the latter, for each nominal antigen, a gate that encompassed beads and B cell rosettes is created followed by the identification of the B cells. Frequency of B cells bound to HLA class I of interest is finally evaluated. Bead-based method allows the detection of antigen-specific B cells. (<b>C</b>). An example of the identification of beads, Bead-cell rosette and lymphocyte is shown. After exclusion of dead cells, the use of the marker CD19 allows the identification of B lymphocyte and a mix of beads and BBR. Thanks to the ratio of two fluorochromes, antigen coated on the beads can be then identified. Beads are excluded using the expression of CD19. A Boolean gate is used to assess the frequency of B cells specific of a given antigen within the whole B cell population.</p

Bead-based method allows the detection of antigen-specific B cells.

<p>(<b>A</b>) B cells purified from Tg mice were incubated with human albumin, MOG_1–125 or pp65 coated beads and the frequency of antigen specific B cells was quantified. The B cells were preincubated with soluble human Albumin, MOG_1–125 or pp65 before incubation with MOG_1–125 coated beads. Data are presented as mean ± sem <b>B</b>). B cells purified from Tg mice were preincubated with increasing doses of soluble MOG_1–125 before incubation with MOG_1–125 coated beads. The experiments were repeated 3 times and similar results were obtained.</p

Enhanced frequency of anti-HLA B cell in immunized patients.

<p><b>A.</b> Using single HLA-A*0201 coated beads, the frequency of B cells specific to HLA-A*0201 allele was assessed in the blood of sensitized transplant recipients with histologically proven antibody mediated rejection (ABMR; n = 10), non-sensitized stable transplant recipients (n = 9) and healthy volunteers (n = 14). Sensitized patients exhibit a significant increase in the frequency of HLA-A*0201 specific B cells compared to non-sensitized patients and healthy volunteers. p value are mentioned (Kruskall-Wallis follow by a Dunn’s post hoc test) <b>B.</b> B cells bound to single HLA class I coated beads (HLA-beads), to negative control (NC) and positive control (PC) were analyzed in HV (n = 16) and Immunized kidney recipients (n = 13). NC and PC beads were included by the manufacture in the single HLA class I kit. According to the manufacture, NC beads are beads saturated with ovalbumin and PC beads are coated with human IgG1. A broad range of single HLA class I were recognized as shown in the insert, a pattern observed for B cells from all tested patients. p value is indicated (Mann-Whitney test).</p

B cells from healthy volunteers exhibit a broad range of reactivity.

<p>Purified B cells from healthy volunteers were tested for their reactivity to albumin (n = 38), Tetanus Toxin (n = 14), EBNA1 (n = 15), MOG_1–125 (n = 38) and a panel of 97 HLA class I molecules (n = 19). ***p<0.001 (Kruskall-Wallis follow by a Dunn’s post hoc test using albumin settings as reference group).</p