HIV-1 treatment timing shapes the human intestinal memory B-cell repertoire to commensal bacteria

HIV-1 infection causes severe alterations of gut mucosa, microbiota and immune system, which can be curbed by early antiretroviral therapy. Here, we investigate how treatment timing affects intestinal memory B-cell and plasmablast repertoires of HIV-1-infected humans. We show that only class-switched memory B cells markedly differ between subjects treated during the acute and chronic phases of infection. Intestinal memory B-cell monoclonal antibodies show more prevalent polyreactive and commensal bacteria-reactive clones in late- compared to early-treated individuals. Mirroring this, serum IgA polyreactivity and commensal-reactivity are strongly increased in late-treated individuals and correlate with intestinal permeability and systemic inflammatory markers. Polyreactive blood IgA memory B cells, many of which egressed from the gut, are also substantially enriched in late-treated individuals. Our data establish gut and systemic B-cell polyreactivity to commensal bacteria as hallmarks of chronic HIV-1 infection and suggest that initiating treatment early may limit intestinal B-cell abnormalities compromising HIV-1 humoral response.

Narrow-band imaging versus Lugol chromoendoscopy for esophageal squamous cell cancer screening in normal endoscopic practice: randomized controlled trial

BACKGROUND

Narrow-band imaging (NBI) is as sensitive as Lugol chromoendoscopy to detect esophageal squamous cell carcinoma (SCC) but its specificity, which appears higher than that of Lugol chromoendoscopy in expert centers, remains to be established in general practice. This study aimed to prove the superiority of NBI specificity over Lugol chromoendoscopy in the detection of esophageal SCC and high grade dysplasia (HGD) in current general practice (including tertiary care centers, local hospitals, and private clinics).

METHODS

This prospective randomized multicenter trial included consecutive patients with previous or current SCC of the upper aerodigestive tract who were scheduled for gastroscopy. Patients were randomly allocated to either the Lugol or NBI group. In the Lugol group, examination with white light and Lugol chromoendoscopy were successively performed. In the NBI group, NBI examination was performed after white-light endoscopy. We compared the diagnostic characteristics of NBI and Lugol chromoendoscopy in a per-patient analysis.

RESULTS

334 patients with history of SCC were included and analyzed (intention-to-treat) from 15 French institutions between March 2011 and December 2015. In per-patient analysis, sensitivity, specificity, positive and negative likelihood values were 100 %, 66.0 %, 21.2 %, and 100 %, respectively, for Lugol chromoendoscopy vs. 100 %, 79.9 %, 37.5 %, and 100 %, respectively, for NBI. Specificity was greater with NBI than with Lugol (P = 0.002).

CONCLUSIONS

As previously demonstrated in expert centers, NBI was more specific than Lugol in current gastroenterology practice for the detection of early SCC, but combined approaches with both NBI and Lugol could improve the detection of squamous neoplasia.

HIV-1 Envelope Recognition by Polyreactive and Cross-Reactive Intestinal B Cells

Mucosal immune responses to HIV-1 involve the recognition of the viral envelope glycoprotein (gp)160 by tissue-resident B cells and subsequent secretion of antibodies. To characterize the B cells “sensing” HIV-1 in the gut of infected individuals, we probed monoclonal antibodies produced from single intestinal B cells binding to recombinant gp140 trimers. A large fraction of mucosal B cell antibodies were polyreactive and showed only low affinity to HIV-1 envelope glycoproteins, particularly the gp41 moiety. A few high-affinity gp140 antibodies were isolated but lacked neutralizing, potent ADCC, and transcytosis-blocking capacities. Instead, they displayed cross-reactivity with defined self-antigens. Specifically, intestinal HIV-1 gp41 antibodies targeting the heptad repeat 2 region (HR2) cluster II cross-reacted with the p38α mitogen-activated protein kinase 14 (MAPK14). Hence, physiologic polyreactivity of intestinal B cells and molecular mimicry-based self-reactivity of HIV-1 antibodies are two independent phenomena, possibly diverting and/or impairing mucosal humoral immunity to HIV-1.

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Polyreactive B cells in HIV-1⁺ intestinal mucosa interact with HIV-1 Env proteins

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High-affinity intestinal HIV-1 gp140 antibodies display poor antiviral activities

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Antibodies targeting the gp41 cluster II region cross-react with MAPK14

Early Antiretroviral Therapy Preserves Functional Follicular Helper T and HIV-Specific B Cells in the Gut Mucosa of HIV-1-Infected Individuals

HIV-1 infection is associated with B cell dysregulation and dysfunction. In HIV-1-infected patients, we previously reported preservation of intestinal lymphoid structures and dendritic cell maturation pathways after early combination antiretroviral therapy (e-ART), started during the acute phase of the infection, compared with late combination antiretroviral therapy started during the chronic phase. In this study, we investigated whether the timing of combination antiretroviral therapy initiation was associated with the development of the HIV-1-specific humoral response in the gut. The results showed that e-ART was associated with higher frequencies of functional resting memory B cells in the gut. These frequencies correlated strongly with those of follicular Th cells in the gut. Importantly, frequencies of HIV-1 Env gp140-reactive B cells were higher in patients given e-ART, in whom gp140-reactive IgG production by mucosal B cells increased after stimulation. Moreover, IL-21 release by PBMCs stimulated with HIV-1 peptide pools was greater with e-ART than with late combination antiretroviral therapy. Thus, early treatment initiation helps to maintain HIV-1-reactive memory B cells in the gut as well as follicular Th cells, whose role is crucial in the development of potent affinity-matured and broadly neutralizing Abs.

Early initiation of combined antiretroviral therapy preserves immune function in the gut of HIV-infected patients

Massive loss of lamina propria CD4(+) T cells, changes in the lymphatic architecture, and altered intestinal epithelial barrier leading to microbial translocation are the common features of HIV-1 infection and are not fully restored under combined antiretroviral therapy (cART). To better understand determinants of gut mucosal restoration, we have performed phenotypic and gene expression analyses of the gut from HIV-infected patients, naive or treated with cART initiated either at the early phase of the primary infection or later during the chronic phase. We found a depletion of T helper type 22 (Th22) and interleukin-17-producing cells in naive patients. These populations, except Th22 cells, were not restored under cART. Regulatory T cells/Th17 ratio was significantly increased in HIV-infected patients and was inversely correlated to the restoration of CD4(+) T cells but not to gut HIV DNA levels. Gene profile analysis of gut mucosal distinguished two groups of patients, which fitted with the timing of cART initiation. In their majority early, but not later treated patients, exhibited conserved intestinal lymphoid structure, epithelial barrier integrity and dendritic cell maturation pathways. Our data demonstrate that early initiation of cART helps to preserve and/or restore lymphoid gut mucosal homeostasis and provide a rationale for initiating cART during the acute phase of HIV infection.

ABCB4 gene mutations and single-nucleotide polymorphisms in women with intrahepatic cholestasis of pregnancy

AIM

To evaluate the nature and frequency of ATP-binding cassette subfamily B member 4 (ABCB4) gene variants in a series of French patients with intrahepatic cholestasis of pregnancy (ICP).

METHODS

In this prospective study, the entire ABCB4 gene coding sequence was analysed by DNA sequencing in 50 unrelated women with ICP defined by pruritus and raised serum alanine aminotransferase activity or bile acid concentration, with recovery after delivery. Genomic variants detected in patients with ICP were sought in 107 control pregnant women. Patients with ICP and controls were of Caucasian origin.

RESULTS

Eight genomic variants were observed. One nonsense mutation (p.Arg144Stop) and two missense mutations (p.Ser320Phe and p.Thr775Met) were revealed each in one heterozygous patient. A third missense mutation (p.Arg590Gln) was detected in three heterozygous patients and in two homozygous patients also homozygous for a particular haplotype of three single-nucleotide polymorphisms (c.175C>T, c.504T>C, c.711A>T). The chromosomal frequency of the p.Arg590Gln variant was significantly different between the ICP and control group (7.0% vs 0.5%; p = 0.0017; OR 16.03, 95% CI 1.94 to 132.16). An association was also found between allele T of the c.504T>C silent nucleotide polymorphism and ICP (68.0% vs 53.7%; p = 0.017; OR 1.83, 95% CI 1.08 to 3.11). The chromosomal frequency of the p.Arg652Gly variant did not differ between the ICP and control group (p = 0.40).

CONCLUSIONS

This study shows that 16% of Caucasian patients with ICP bear ABCB4 gene mutations, and confirms the significant involvement of this gene in the pathogenesis of this complex disorder.

Neutropénie et thrombopénie auto-immunes sévères associées à une hépatite chronique C : effet du traitement antiviral

We report the case of a 45-year-old man admitted for severe autoimmune thrombopenia and neutropenia associated with chronic viral C hepatitis. After failed, intravenous gammaglobulin and corticosteroid therapy antiviral treatment with interferon and ribavirin was given for one year. Thrombopenia improved progressively during antiviral therapy and worsened after the end of treatment. Neutropenia improved during antiviral therapy. Two years after the end of treatment, serum RNA-HCV was positive, white cell count was normal and platelet count was 77 G/L. In conclusion, these results suggest that antiviral therapy may be useful in patients with auto-immune cytopenia associated with viral hepatitis C infection.