A prospective study of serum microbial translocation biomarkers and risk of AIDS-related non-Hodgkin lymphoma

Characterization of unique B-cell populations in the circulation of people living with HIV prior to non-Hodgkin lymphoma diagnosis

People living with HIV (PLWH) are at higher risk of developing lymphoma. In this study, we performed cytometry by time-of-flight (CyTOF) on peripheral blood mononuclear cells of cART-naïve HIV+ individuals and cART-naïve HIV+ individuals prior to AIDS-associated non-Hodgkin lymphoma (pre-NHL) diagnosis. Participants were enrolled in the Los Angeles site of the MACS/WIHS Combined Cohort Study (MWCCS). Uniform Manifold Approximation and Projection (UMAP) and unsupervised clustering analysis were performed to identify differences in the expression of B-cell activation markers and/or oncogenic markers associated with lymphomagenesis. CD10+CD27- B cells, CD20+CD27- B cells, and B-cell populations with aberrant features (CD20+CD27+CXCR4+CD71+ B cells and CD20+CXCR4+cMYC+ B cells) were significantly elevated in HIV+ cART-naïve compared to HIV-negative samples. CD20+CD27+CD24+CXCR4+CXCR5+ B cells, CD20+CD27+CD10+CD24+CXCR4+cMYC+ B cells, and a cluster of CD20+CXCR4hiCD27-CD24+CXCR5+CD40+CD4+AICDA+ B cells were significantly elevated in HIV+ pre-NHL (cART-naïve) compared to HIV+ cART-naïve samples. A potentially clonal cluster of CD20+CXCR4+CXCR5+cMYC+AICDA+ B cells and a cluster of germinal center B-cell-like cells (CD19-CD20+CXCR4+Bcl-6+PD-L1+cMYC+) were also found in the circulation of HIV+ pre-NHL (cART-naïve) samples. Moreover, significantly elevated clusters of CD19+CD24hiCD38hi cMYC+ AICDA+ B regulatory cells were identified in HIV+ pre-NHL (cART-naïve) compared to HIV+ cART-naïve samples. The present study identifies unique B-cell subsets in PLWH with potential pre-malignant features that may contribute to the development of pre-tumor B cells in PLWH and that may play a role in lymphomagenesis.

Menopause and Estrogen Associations With Gut Barrier, Microbial Translocation, and Immune Activation Biomarkers in Women With and Without HIV

OBJECTIVES

Estrogens may protect the gut barrier and reduce microbial translocation and immune activation, which are prevalent in HIV infection. We investigated relationships of the menopausal transition and estrogens with gut barrier, microbial translocation, and immune activation biomarkers in women with and without HIV.

DESIGN

Longitudinal and cross-sectional studies nested in the Women's Interagency HIV Study.

METHODS

Intestinal fatty acid binding protein, lipopolysaccharide binding protein, and soluble CD14 (sCD14) levels were measured in serum from 77 women (43 with HIV) before, during, and after the menopausal transition (∼6 measures per woman over ∼13 years). A separate cross-sectional analysis was conducted among 72 postmenopausal women with HIV with these biomarkers and serum estrogens.

RESULTS

Women in the longitudinal analysis were a median age of 43 years at baseline. In piecewise, linear, mixed-effects models with cutpoints 2 years before and after the final menstrual period to delineate the menopausal transition, sCD14 levels increased over time during the menopausal transition (Beta [95% CI]: 38 [12 to 64] ng/mL/yr, P = 0.004), followed by a decrease posttransition (-46 [-75 to -18], P = 0.001), with the piecewise model providing a better fit than a linear model (P = 0.0006). In stratified analyses, these results were only apparent in women with HIV. In cross-sectional analyses, among women with HIV, free estradiol inversely correlated with sCD14 levels (r = -0.26, P = 0.03). Lipopolysaccharide binding protein and intestinal fatty acid binding protein levels did not appear related to the menopausal transition and estrogen levels.

CONCLUSIONS

Women with HIV may experience heightened innate immune activation during menopause, possibly related to the depletion of estrogens.

Soy Protein Concentrate Diets Inversely Affect LPS-Binding Protein Expression in Colon and Liver, Reduce Liver Inflammation, and Increase Fecal LPS Excretion in Obese Zucker Rats

Dietary soy protein and soy isoflavones have anti-inflammatory properties. Previously, we reported that feeding soy protein concentrate diet (SPC) with low or high isoflavone (LIF or HIF) to young (seven-week-old) obese (fa/fa) Zucker rats inhibits lipopolysaccharide (LPS) translocation and decreases liver inflammation compared to a casein control (CAS) diet. The current study investigated whether SPC-LIF and SPC-HIF diets would reduce liver inflammation in adult obese Zucker rats fed a CAS diet. A total of 21 six-week-old male obese (fa/fa) Zucker rats were given CAS diet for 8 weeks to develop obesity then randomly assigned to CAS, SPC-LIF, or SPC-HIF (seven rats/group) diet for an additional 10 weeks. The expression of LPS-translocation, inflammation, and intestinal permeability markers were quantified by qPCR in liver, visceral adipose tissue (VAT), and colon. LPS concentration was determined in both the colon content and fecal samples by a Limulus amebocyte lysate (LAL) test. SPC-LIF and SPC-HIF diets significantly decreased liver LPS-binding protein (LBP) expression compared to CAS diet (p < 0.01 and p < 0.05, respectively). SPC-HIF diet also significantly decreased liver MCP-1 and TNF-α expression (p < 0.05) and had a trend to decrease liver iNOS expression (p = 0.06). In the colon, SPC-HIF diet significantly increased LBP expression compared to CAS diet (p < 0.05). When samples from all three groups were combined, there was a negative correlation between colon LBP expression and liver LBP expression (p = 0.046). SPC diets did not alter the expression of intestinal permeability markers (i.e., occludin, claudin 3, and zonula occludens-1) in the colon or inflammation markers (i.e., TNF-α and iNOS) in VAT or the colon. LPS levels in the colon content did not differ between any groups. Fecal LPS levels were significantly higher in the SPC-LIF and SPC-HIF groups compared to the CAS group (p < 0.01). In conclusion, SPC, particularly SPC with HIF, reduces liver LBP expression and inflammation makers (i.e., TNF-α and MCP-1 expression) in adult obese Zucker rats, likely by reducing LPS translocation.

Effect of immunological non-response on incidence of Non-AIDS events in people living with HIV: A retrospective multicenter cohort study in Taiwan

BACKGROUND

People living with HIV (PLWH) are susceptible to non-AIDS-related events, particularly those with immunological nonresponses (INRs) to highly active antiretroviral therapy (HAART). This study assessed the association of INRs with incident non-AIDS-related events among PLWH.

METHODS

This multicenter retrospective cohort study enrolled PLWH who had newly diagnosed stage 3 HIV and received HAART between January 1, 2008, and December 31, 2019. The patients were divided into two groups according to their immunological responses on the 360th day after HAART initiation: INR and non-INR groups. Cox regression and sensitivity analyses were conducted to estimate the effects of INRs on overall and individual categories of non-AIDS-related events (malignancies, vascular diseases, metabolic disorders, renal diseases, and psychiatric disorders). Patient observation started on the 360th day after HAART initiation and continued until February 28, 2022, death, or an outcome of interest, whichever occurred first.

RESULTS

Among the 289 included patients, 44 had INRs. Most of the included patients were aged 26-45 years (69.55%) and were men who have sex with men (89.97%). Many patients received HIV diagnoses between 2009 and 2012 (38.54%). INRs (vs. non-INRs) were associated with composite non-AIDS-related events (adjusted hazard ratio [aHR] = 1.80; 95% confidence interval [CI]: 1.19-2.73) and metabolic disorders (aHR = 1.75; 95% CI: 1.14-2.68). Sensitivity analyses revealed consistent results for each Cox regression model for both composite non-AIDS-related events and metabolic diseases.

CONCLUSION

Clinicians should be vigilant and implement early intervention and rigorous monitoring for non-AIDS-related events in PLWH with INRs to HAART.

Extracellular vesicles as biomarkers for AIDS-associated non-Hodgkin lymphoma risk

Introduction

Extracellular vesicles are membrane-bound structures secreted into the extracellular milieu by cells and can carry bioactive molecules. There is emerging evidence suggesting that EVs play a role in the diagnosis, treatment, and prognosis of certain cancers. In this study, we investigate the association of EVs bearing PD-L1 and molecules important in B-cell activation and differentiation with AIDS-NHL risk.

Methods

EVs were isolated from archived serum collected prior to the diagnosis of AIDS-NHL in cases (N = 51) and matched HIV+ controls (N = 52) who were men enrolled in the Los Angeles site of the MACS/WIHS Combined Cohort Study (MWCCS). Serum specimens of AIDS-NHL cases were collected at a mean time of 1.25 years (range of 2 to 36 months) prior to an AIDS-NHL diagnosis. The expression of PD-L1 and other molecules on EVs (CD40, CD40L, TNF-RII, IL-6Rα, B7-H3, ICAM-1, and FasL) were quantified by Luminex multiplex assay.

Results and discussion

We observed significantly higher levels of EVs bearing PD-L1, CD40, TNF-RII and/or IL-6Rα in AIDS-NHL cases compared with controls. Using multivariate conditional logistic regression models adjusted for age and CD4+ T-cell count, we found that EVs bearing PD-L1 (OR = 1.93; 95% CI: 1.10 - 3.38), CD40 (OR = 1.97, 95% CI: 1.09 - 3.58), TNF-RII (OR = 5.06; 95% CI: 1.99 - 12.85) and/or IL-6Rα (OR = 4.67; 95% CI: 1.40 - 15.53) were significantly and positively associated with AIDS-NHL risk. In addition, EVs bearing these molecules were significantly and positively associated with non-CNS lymphoma: PD-L1 (OR = 1.94; 95% CI: 1.01 - 3.72); CD40 (OR = 2.66; 95% CI: 1.12 - 6.35); TNF-RII (OR = 9.64; 95% CI: 2.52 - 36.86); IL-6Rα (OR = 8.34; 95% CI: 1.73 - 40.15). These findings suggest that EVs bearing PD-L1, CD40, TNF-RII and/or IL-6Rα could serve as biomarkers for the early detection of NHL in PLWH.

Human Immunodeficiency Virus Related Non-Hodgkin's Lymphoma

Human immunodeficiency virus infection is related with an increased risk of hematological malignancy principally, non-Hodgkin lymphoma. Most non-Hodgkin lymphomas are acquired immunodeficiency syndrome defining and constitute greater than 50% of all acquired immunodeficiency syndrome defining cancers. The main pathogenesis mechanisms are immunodeficiency, chronic antigenic stimulation, and the ability to infect cancer cells causing direct carcinogenesis. Human immunodeficiency virus related non-Hodgkin lymphomas are heterogeneous in immunophenotyping and molecular features; and choice of drug treatments is similar with sporadic types. The main objective is to assess the epidemiology, pathogenesis, and morphology of human immunodeficiency virus related non-Hodgkin lymphoma. The searching strategy was done by searching relevant original and review articles from www.biosemanticjane/org, Google scholar, Google, and PubMed sites using keywords like; Acquired immunodeficiency syndrome, Human immunodeficiency virus, and non-Hodgkin lymphoma. In conclusion, human immunodeficiency virus infected people continue to have elevated risk of non-Hodgkin lymphoma. Diffuse large B-cell lymphomas are the most common and severe subtype. The pathogenesis of this type of lymphoma is associated with chromosomal abnormalities that deregulate the expression of various oncogenes by different viral particles and cytokines. However, the role of these viral particles and cytokines on pathogenesis is not clearly stated, so further study could be required.

Circulating markers of microbial translocation and host response to bacteria with risk of colorectal cancer: a prospective, nested case-control study in men

BACKGROUND

Gut microbial dysbiosis contributes to colorectal cancer (CRC) pathogenesis, possibly mediated in part by increased intestinal permeability to endotoxin lipopolysaccharide (LPS), microbial translocation, and subsequent endotoxemia and inflammation. However, epidemiologic evidence linking circulating markers of microbial translocation with CRC risk is limited.

METHODS

We conducted a prospective, nested case-control study of 261 incident CRC cases and 261 controls (matched on age and time of blood draw) among 18,159 men with pre-diagnostic blood specimens in the Health Professionals Follow-Up Study (1993-2009). We examined three complementary markers of microbial translocation and host response to bacteria, including LPS-binding protein (LBP), soluble CD14 (sCD14), and endotoxincore antibody (EndoCAb) immunoglobulin M (IgM), with subsequent risk of CRC. Unconditional logistic regressions were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

FINDINGS

Pre-diagnostic circulating levels of sCD14 were associated with a higher risk of incident CRC. Compared to men in the lowest quartile, the multivariable OR was 1.90 (95% CI, 1.13-3.22) for men in the highest quartile (OR _{per standard deviation [SD] increase}, 1.28; 95%CI 1.06-1.53; P_trend = 0.01). This positive association remained similar after adjusting for C-reactive protein, interleukin-6, and soluble tumor necrosis factor receptor-2, and within strata of putative CRC risk factors. We also observed a suggestive inverse association between EndoCAb IgM and risk of CRC (OR _{per SD increase}, 0.84; 95%CI 0.69-1.02; P_trend = 0.09).

INTERPRETATION

Microbial translocation and host response to bacteria, as reflected by sCD14, is associated with risk of incident CRC in men.

FUNDING

US National Institutes of Health.

16S rDNA sequencing analyzes differences in intestinal flora of human immunodeficiency virus (HIV) patients and association with immune activation

To clarify the influence of HIV on the intestinal flora and the interrelationship with CD4 T cells, the present study collected stool specimens from 33 HIV patients and 28 healthy subjects to compare the differences in the intestinal flora and CD4 T cells in a 16S rDNA-sequencing approach. ELISA was used to detect the expressions of interleukin 2 (IL-2), IL-8, and tumor necrosis factor-α (TNF-α). Meanwhile, correlation analysis with the different bacterial populations in each group was carried out. The results revealed that Alpha diversity indices of the intestinal flora of HIV patients were markedly lower than that of the healthy group (p < 0.05). The top five bacterial species in the HIV group were Bacteroides (23.453%), Prevotella (19.237%), Fusobacterium (12.408%), Lachnospira (3.811%), and Escherichia-Shigella (3.126%). Spearman correlation analysis results indicated that Fusobacterium_mortiferum, Fusobacterium, and Gammaproteobacteria were positively correlated with TNF-α (p < 0.05), whereas Ruminococcaceae, Bacteroidales was negatively correlated with TNF-α (p < 0.05). Additionally, Agathobacter was positively correlated with contents of IL-2 and IL-8 (p < 0.05), whereas Prevotellaceae, and Prevotella were negatively correlated with IL-8 content (p < 0.05). Furthermore, the top five strains in the CD4 high group (≥350/mm³) included Bacteroides (23.286%), Prevotella (21.943%), Fusobacterium (10.479%), Lachnospira (4.465%), and un_f_Lachnospiraceae (2.786%). Taken together, the present study identified that Fusobacterium and Escherichia-Shigella were specific and highly abundant in the HIV group and a correlation between the different bacterial flora and the contents of IL-2, IL-8, and TNF-α was revealed.

Aging With Grace for People Living With HIV: Strategies to Overcome Leaky Gut and Cytomegalovirus Coinfection

ABSTRACT

The intestinal epithelial layer acts as a mechanical and functional barrier between the intraluminal microbiota and the immunologically active submucosa. A progressive loss of gut barrier function (leaky gut) leads to enhanced translocation of microbial products, which in turn contributes as endotoxins to inflammaging. Th17 T cell represents the main immune sentinels in the gut epithelium, preventing aggression from commensal and pathogenic microbes. As HIV infection deeply affects gut Th17 function and increases gut permeability, microbial translocation occurs at high level in people living with HIV (PLWH) and has been associated with the development of non-AIDS comorbidities. Although the inflammatory role of endotoxins like lipopolysaccharide produced by Gram-negative bacteria is well-established, fungal products such as β-D-glucan emerge as new contributors. In addition, PLWH are more frequently infected with cytomegalovirus (CMV) than the general population. CMV infection is a well-described accelerator of immune aging, through the induction of expansion of dysfunctional CD8 T-cells as well as through enhancement of gut microbial translocation. We critically review immune mechanisms related to bacterial and fungal translocation, with a focus on the contribution of CMV coinfection in PLWH. Improving gut barrier dysfunction, microbial composition, and reducing microbial translocation constitute emerging strategies for the prevention and treatment of HIV-associated inflammation and may be relevant for age-related inflammatory conditions.

Lymphoma-Associated Biomarkers Are Increased in Current Smokers in Twin Pairs Discordant for Smoking

Simple Summary

Smoking is associated with a moderate increased risk of Hodgkin and follicular lymphoma. To help understand why, we examined lymphoma-related biomarker levels among 134 smoking and non-smoking twins (67 pairs) ascertained from the Finnish Twin Cohort. We validated self-reported smoking history by measuring serum cotinine, a metabolite of nicotine, from previously collected frozen serum samples. In total, 27 immune biomarkers were assayed using the Luminex Multiplex platform (R & D Systems). We found that four immune response biomarkers were higher and one was lower among smoking compared to non-smoking twins. The strongest association was observed for CCL17/TARC, a biomarker elevated in Hodgkin lymphoma patients. Immune biomarker levels were similar in former smokers and non-smokers. Current smoking may increase levels of immune proteins that could partially explain the association between smoking and risk of certain lymphomas.

Abstract

Smoking is associated with a moderate increased risk of Hodgkin and follicular lymphoma. To understand why, we examined lymphoma-related biomarker levels among 134 smoking and non-smoking twins (67 pairs) ascertained from the Finnish Twin Cohort. Previously collected frozen serum samples were tested for cotinine to validate self-reported smoking history. In total, 27 immune biomarkers were assayed using the Luminex Multiplex platform (R & D Systems). Current and non-current smokers were defined by a serum cotinine concentration of >3.08 ng/mL and ≤3.08 ng/mL, respectively. Associations between biomarkers and smoking were assessed using linear mixed models to estimate beta coefficients and standard errors, adjusting for age, sex and twin pair as a random effect. There were 55 never smokers, 43 current smokers and 36 former smokers. CCL17/TARC, sgp130, haptoglobin, B-cell activating factor (BAFF) and monocyte chemoattractant protein-1 (MCP1) were significantly (p < 0.05) associated with current smoking and correlated with increasing cotinine concentrations (P_trend < 0.05). The strongest association was observed for CCL17/TARC (P_trend = 0.0001). Immune biomarker levels were similar in former and never smokers. Current smoking is associated with increased levels of lymphoma-associated biomarkers, suggesting a possible mechanism for the link between smoking and risk of these two B-cell lymphomas.

Targeting TfR1 with the ch128.1/IgG1 Antibody Inhibits EBV-driven Lymphomagenesis in Immunosuppressed Mice Bearing EBV+ Human Primary B-cells

Epstein-Barr virus (EBV) is a human gammaherpesvirus associated with the development of hematopoietic cancers of B-lymphocyte origin, including AIDS-related non-Hodgkin lymphoma (AIDS-NHL). Primary infection of B-cells with EBV results in their polyclonal activation and immortalization. The transferrin receptor 1 (TfR1), also known as CD71, is important for iron uptake and regulation of cellular proliferation. TfR1 is highly expressed in proliferating cells, including activated lymphocytes and malignant cells. We developed a mouse/human chimeric antibody targeting TfR1 (ch128.1/IgG1) that has previously shown significant antitumor activity in immunosuppressed mouse models bearing human malignant B-cells, including multiple myeloma and AIDS-NHL cells. In this article, we examined the effect of targeting TfR1 to inhibit EBV-driven activation and growth of human B-cells in vivo using an immunodeficient NOD.Cg-Prkdcscid Il2rgtm1Wjl /SzJ [NOD/SCID gamma (NSG)] mouse model. Mice were implanted with T-cell-depleted, human peripheral blood mononuclear cells (PBMCs), either without EBV (EBV-), or exposed to EBV in vitro (EBV+), intravenously via the tail vein. Mice implanted with EBV+ cells and treated with an IgG1 control antibody (400 μg/mouse) developed lymphoma-like growths of human B-cell origin that were EBV+, whereas mice implanted with EBV+ cells and treated with ch128.1/IgG1 (400 μg/mouse) showed increased survival and significantly reduced inflammation and B-cell activation. These results indicate that ch128.1/IgG1 is effective at preventing the growth of EBV+ human B-cell tumors in vivo, thus, indicating that there is significant potential for agents targeting TfR1 as therapeutic strategies to prevent the development of EBV-associated B-cell malignancies. SIGNIFICANCE: An anti-TfR1 antibody, ch128.1/IgG1, effectively inhibits the activation, growth, and immortalization of EBV+ human B-cells in vivo, as well as the development of these cells into lymphoma-like tumors in immunodeficient mice.

Immune Activation and Microbial Translocation as Prognostic Biomarkers for AIDS-Related Non-Hodgkin Lymphoma in the AMC-034 Study

PURPOSE

AIDS-related non-Hodgkin lymphoma (ARL) is the most common cancer in HIV-infected individuals in the United States and other countries in which HIV-positive persons have access to effective combination antiretroviral therapy (cART). Our prior work showed that pretreatment/postdiagnosis plasma levels of some cytokines, such as IL6, IL10, and CXCL13, have the potential to serve as indicators of clinical response to treatment and survival in ARL. The aims of this study were to identify novel prognostic biomarkers for response to treatment and/or survival in persons with ARL, including biomarkers of microbial translocation and inflammation.

EXPERIMENTAL DESIGN

We quantified plasma levels of several biomarkers (sCD14, LBP, FABP2, EndoCab IgM, IL18, CCL2/MCP-1, sCD163, IP-10/CXCL10, TARC/CCL17, TNFα, BAFF/BLyS, sTNFRII, sCD44, and sIL2Rα/sCD25) by multiplexed immunometric assays (Luminex) or ELISA in plasma specimens obtained from ARL patients enrolled in the AMC-034 trial, which compared infusional combination chemotherapy (EPOCH: etoposide, vincristine, doxorubicin, cyclophosphamide, and prednisone) with concurrent or sequential rituximab. Plasma was collected prior to the initiation of therapy (n = 57) and after treatment initiation (n = 55).

RESULTS

We found that several biomarkers decreased significantly after treatment, including TNFα, sCD25, LBP, and TARC (CCL17). Moreover, pretreatment plasma levels of BAFF, sCD14, sTNFRII, and CCL2/MCP-1 were univariately associated with overall survival, and pretreatment levels of BAFF, sTNFRII, and CCL2/MCP-1 were also associated with progression-free survival.

CONCLUSIONS

Our results suggest that patients with ARL who responded to therapy had lower pretreatment levels of inflammation and microbial translocation as compared with those who did not respond optimally.

Effect of Statin Use on Inflammation and Immune Activation Biomarkers in HIV-Infected Persons on Effective Antiretroviral Therapy

Immune activation and inflammation are hallmarks of chronic HIV infection and are etiologically linked to major causes of morbidity and mortality among HIV-infected persons, including coronary artery disease and cancer. Systemic immune activation is dampened, but not resolved, with use of combination antiretroviral therapy (cART). Statins are cardioprotective drugs that also appear to have immunomodulatory and anti-inflammatory properties. We sought to understand the association between statin use, cART, and levels of circulating immune markers in a longitudinal cohort study. From 2004 to 2009, statin use was ascertained in male participants of the Multicenter AIDS Cohort Study (MACS) using interviewer-administered questionnaires. Twenty-four circulating markers of immune activation and inflammation were measured in archived serial samples from a subset of cohort members using multiplex assays. Propensity-adjusted generalized gamma models were used to compare biomarkers' distributions by statin use, and multivariable linear regression models were used to assess the effect of initiating statin on these biomarkers. Overall, 1,031 cART-exposed individuals with HIV infection were included in this study. Statin use was reported by 31.5% of cART-exposed participants. Compared to nonstatin users on cART, statin users on cART had lower levels of IP-10, IL-10, and IL-12p70, and the effect of statin use was decreased in participants using lipophilic statins (atorvastatin, simvastatin, fluvastatin, or lovastatin); these results were statistically significant (p < .05). Among cART users not on aspirin, starting statins decreased levels of high sensitivity c-reactive protein (hsCRP), IL-12p70, and IL-6. Statin therapy is associated with reduced levels of certain biomarkers of immune activation and inflammation in cART users, which may contribute to a lower burden of disease.

Gut Leakage of Fungal-Related Products: Turning Up the Heat for HIV Infection

The intestinal epithelial layer serves as a physical and functional barrier between the microbiota in the lumen and immunologically active submucosa. Th17 T-cell function protects the gut epithelium from aggression from microbes and their by-products. Loss of barrier function has been associated with enhanced translocation of microbial products which act as endotoxins, leading to local and systemic immune activation. Whereas the inflammatory role of LPS produced by Gram-negative bacteria has been extensively studied, the role of fungal products such as β-D-glucan remains only partially understood. As HIV infection is characterized by impaired gut Th17 function and increased gut permeability, we critically review mechanisms of immune activation related to fungal translocation in this viral infection. Additionally, we discuss markers of fungal translocation for diagnosis and monitoring of experimental treatment responses. Targeting gut barrier dysfunction and reducing fungal translocation are emerging strategies for the prevention and treatment of HIV-associated inflammation and may prove useful in other inflammatory chronic diseases.

The role of soluble mediators in the clinical course of EBV infection and B cell homeostasis after kidney transplantation

Epstein-Barr virus (EBV) reactivation can lead to serious complications in kidney transplant patients, including post-transplant lymphoproliferative disorder (PTLD). Here, we have assessed the impact of EBV on B cell homeostasis at cellular and humoral level. In a multicenter study monitoring 540 kidney transplant patients during the first post-transplant year, EBV reactivation was detected in 109 patients. Thirteen soluble factors and B cell counts were analyzed in an EBV+ sub-cohort (N = 54) before, at peak and after EBV clearance and compared to a control group (N = 50). The B cell activating factor (BAFF) was significantly elevated among EBV+ patients. No additional soluble factors were associated with EBV. Importantly, in vitro experiments confirmed the proliferative effect of BAFF on EBV-infected B cells, simultaneously promoting EBV production. In contrast, elevated levels of BAFF in EBV+ patients did not lead to B cell expansion in vivo. Moreover, diminished positive inter-correlations of soluble factors and alterations of the bi-directional interplay between B cell and soluble factors were observed in EBV+ patients at peak and after clearance. Our data suggest that such alterations may counteract the proliferative effect of BAFF, preventing B cell expansion. The role of these alterations in lymphoma development should be analyzed in future studies.

Daily variations of gut microbial translocation markers in ART-treated HIV-infected people

Background

Increased intestinal barrier permeability and subsequent gut microbial translocation are significant contributors to inflammatory non-AIDS comorbidities in people living with HIV (PLWH). Evidence in animal models have shown that markers of intestinal permeability and microbial translocation vary over the course of the day and are affected by food intake and circadian rhythms. However, daily variations of these markers are not characterized yet in PLWH. Herein, we assessed the variation of these markers over 24 h in PLWH receiving antiretroviral therapy (ART) in a well-controlled environment.

Methods

As in Canada, PLWH are predominantly men and the majority of them are now over 50 years old, we selected 11 men over 50 receiving ART with undetectable viremia for more than 3 years in this pilot study. Blood samples were collected every 4 h over 24 h before snacks/meals from 8:00 in the morning to 8:00 the next day. All participants consumed similar meals at set times, and had a comparable amount of sleep, physical exercise and light exposure. Plasma levels of bacterial lipopolysaccharide (LPS) and fungal (1→3)-β-D-Glucan (BDG) translocation markers, along with markers of intestinal damage fatty acid binding protein (I-FABP) and regenerating islet-derived protein-3α (REG3α) were assessed by ELISA or the fungitell assay.

Results

Participants had a median age of 57 years old (range 50 to 63). Plasma levels of BDG and REG3α did not vary significantly over the course of the study. In contrast, a significant increase of LPS was detected between 12:00 and 16:00 (Z-score: − 1.15 ± 0.18 vs 0.16 ± 0.15, p = 0.02), and between 12:00 and 24:00 (− 1.15 ± 0.18 vs 0.89 ± 0.26, p < 0.001). The plasma levels of I-FABP at 16:00 (− 0.92 ± 0.09) were also significantly lower, compared to 8:00 the first day (0.48 ± 0.26, p = 0.002), 4:00 (0.73 ± 0.27, p < 0.001) or 8:00 on secondary day (0.88 ± 0.27, p < 0.001).

Conclusions

Conversely to the fungal translocation marker BDG and the gut damage marker REG3α, time of blood collection matters for the proper evaluation for LPS and I-FABP as markers for the risk of inflammatory non-AIDS co-morbidities. These insights are instrumental for orienting clinical investigations in PLWH.

Gut permeability, inflammation, and bone density across the menopause transition

BACKGROUNDInflammation is implicated in many aging-related disorders. In animal models, menopause leads to increased gut permeability and inflammation. Our primary objective was to determine if gut permeability increases during the menopause transition (MT) in women. Our exploratory objectives were to examine whether greater gut permeability is associated with more inflammation and lower bone mineral density (BMD).METHODSWe included 65 women from the Study of Women's Health Across the Nation (SWAN). Key measures were markers of gut permeability (gut barrier dysfunction, fatty acid binding protein 2 [FABP2]) and immune activation secondary to gut microbial translocation (LPS binding protein [LBP], soluble CD14 [sCD14]), inflammation (high-sensitivity CRP), and lumbar spine (LS) or total hip (TH) BMD.RESULTSIn our primary analysis, FABP2, LBP, and sCD14 increased by 22.8% (P = 0.001), 3.7% (P = 0.05), and 8.9% (P = 0.0002), respectively, from pre- to postmenopause. In exploratory, repeated measures, mixed-effects linear regression (adjusted for BMI, age at the premenopausal visit, race/ethnicity, and study site), greater gut permeability was associated with greater inflammation, along with lower LS and TH BMD.CONCLUSIONGut permeability increases during the MT. Greater gut permeability is associated with more inflammation and lower BMD. Future studies should examine the longitudinal associations of gut permeability, inflammation, and BMD.FUNDINGFunding for this research was provided by NIH, Department of Health and Human Services, through the National Institute on Aging, National Institute of Nursing Research, and NIH Office of Research on Women's Health (U01NR004061, U01AG012505, U01AG012535, U01AG012531, U01AG012539, U01AG012546, U01AG012553, U01AG012554, and U01AG012495).

The Role of Microbial Translocation and Immune Activation in AIDS-Associated Non-Hodgkin Lymphoma Pathogenesis: What Have We Learned?

Human immunodeficiency virus (HIV) infection is associated with greatly increased risk for development of non-Hodgkin lymphoma (NHL). Nearly all acquired immunodeficiency syndrome (AIDS)-associated NHL (AIDS-NHL) is of B-cell origin. Two major mechanisms are believed to contribute to the genesis of AIDS-NHL: (1) loss of immunoregulation of Epstein-Barr virus (EBV)+ B cells, resulting from impaired T-cell function late in the course of HIV disease and (2) chronic B-cell activation, leading to DNA-modifying events that contribute to oncogene mutations/ translocations. HIV infection has long been known to be associated with chronic inflammation and polyclonal B-cell activation, and more recently, microbial translocation. Microbial translocation is bacterial product leakage from gut lumen into the peripheral circulation, resulting in high levels of lipopolysaccharide (LPS) in the peripheral circulation, leading to chronic immune activation and inflammation. We review recent literature linking microbial translocation to lymphom-agenesis. This includes epidemiological studies of biomarkers of microbial translocation with risk of AIDS-NHL and emerging data on the mechanisms by which microbial translocation may lead to AIDS-NHL development.

Microbial Translocation Is Linked to a Specific Immune Activation Profile in HIV-1-Infected Adults With Suppressed Viremia

Persistent immune activation in virologically suppressed HIV-1 patients, which may be the consequence of various factors including microbial translocation, is a major cause of comorbidities. We have previously shown that different profiles of immune activation may be distinguished in virological responders. Here, we tested the hypothesis that a particular profile might be the consequence of microbial translocation. To this aim, we measured 64 soluble and cell surface markers of inflammation and CD4+ and CD8+ T-cell, B cell, monocyte, NK cell, and endothelial activation in 140 adults under efficient antiretroviral therapy, and classified patients and markers using a double hierarchical clustering analysis. We also measured the plasma levels of the microbial translocation markers bacterial DNA, lipopolysaccharide binding protein (LBP), intestinal-fatty acid binding protein, and soluble CD14. We identified five different immune activation profiles. Patients with an immune activation profile characterized by a high percentage of CD38+CD8+ T-cells and a high level of the endothelial activation marker soluble Thrombomodulin, presented with higher LBP mean (± SEM) concentrations (33.3 ± 1.7 vs. 28.7 ± 0.9 μg/mL, p = 0.025) than patients with other profiles. Our data are consistent with the hypothesis that the immune activation profiles we described are the result of different etiological factors. We propose a model, where particular causes of immune activation, as microbial translocation, drive particular immune activation profiles responsible for particular comorbidities.

AllergoOncology: Microbiota in allergy and cancer-A European Academy for Allergy and Clinical Immunology position paper

The microbiota can play important roles in the development of human immunity and the establishment of immune homeostasis. Lifestyle factors including diet, hygiene, and exposure to viruses or bacteria, and medical interventions with antibiotics or anti-ulcer medications, regulate phylogenetic variability and the quality of cross talk between innate and adaptive immune cells via mucosal and skin epithelia. More recently, microbiota and their composition have been linked to protective effects for health. Imbalance, however, has been linked to immune-related diseases such as allergy and cancer, characterized by impaired, or exaggerated immune tolerance, respectively. In this AllergoOncology position paper, we focus on the increasing evidence defining the microbiota composition as a key determinant of immunity and immune tolerance, linked to the risk for the development of allergic and malignant diseases. We discuss novel insights into the role of microbiota in disease and patient responses to treatments in cancer and in allergy. These may highlight opportunities to improve patient outcomes with medical interventions supported through a restored microbiome.

Serological Assessment of 18 Pathogens and Risk of AIDS-Associated Non-Hodgkin Lymphoma

BACKGROUND

HIV infection is associated with increased susceptibility to common pathogens, which may trigger chronic antigenic stimulation and hyperactivation of B cells, events known to precede the development of AIDS-associated non-Hodgkin lymphoma (AIDS-NHL).

METHODS

To explore whether cumulative exposure to infectious agents contributes to AIDS-NHL risk, we tested sera from 199 AIDS-NHL patients (pre-NHL, average lead time 3.9 years) and 199 matched HIV-infected controls from the Multicenter AIDS Cohort Study, for anti-IgG responses to 18 pathogens using multiplex serology. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression models.

RESULTS

We found no association between cumulative exposure to infectious agents and AIDS-NHL risk (OR 1.01, 95% CI: 0.91 to 1.12). However, seropositivity for trichodysplasia spinulosa polyomavirus (TSPyV), defined as presence of antibodies to TSPyV capsid protein VP1, was significantly associated with a 1.6-fold increase in AIDS-NHL risk (OR 1.62, 95% CI: 1.02 to 2.57). High Epstein-Barr virus (EBV) anti-VCA p18 antibody levels closer to the time of AIDS-NHL diagnosis (<4 years) were associated with a 2.6-fold increase in AIDS-NHL risk (OR 2.59, 95% CI: 1.17 to 5.74). In addition, high EBV anti-EBNA-1 and anti-ZEBRA antibody levels were associated with 2.1-fold (OR 0.47, 95% CI: 0.26 to 0.85) and 1.6-fold (OR 0.57, 95% CI: 0.35 to 0.93) decreased risk of AIDS-NHL, respectively.

CONCLUSIONS

Our results do not support the hypothesis that cumulative exposure to infectious agents contributes to AIDS-NHL development. However, the observed associations with respect to TSPyV seropositivity and EBV antigen antibody levels offer additional insights into the pathogenesis of AIDS-NHL.

Donor-specific Antibodies, Immunoglobulin-free Light Chains, and BAFF Levels in Relation to Risk of Late-onset PTLD in Liver Recipients

Background

Posttransplant lymphoproliferative disorder (PTLD) is a neoplastic complication of transplantation, with early cases largely due to immunosuppression and primary Epstein-Barr virus infection. Etiology may differ for later-onset cases, but the contributions of immunosuppression, immune reactivity to the donor organ, and chronic B cell activation are uncertain.

Methods

We conducted a case-control study of late-onset PTLD (diagnosed >1 year posttransplant) in a cohort of liver recipients. We assessed serum samples (obtained >6 months before diagnosis in cases) from N = 60 cases and N = 166 matched controls for donor-specific antibodies (DSAs, evaluable for N = 221 subjects), immunoglobulin kappa and lambda free light chains (FLCs, N = 137), and B cell activating factor (BAFF, N = 226). Conditional or unconditional logistic regression was used to calculate adjusted odds ratios (aORs).

Results

Circulating DSAs were less common in PTLD cases than controls (18% vs 30%), although this difference was borderline significant (aOR, 0.51; 95% confidence interval [CI], 0.24-1.10; P = 0.09). Donor-specific antibodies against class II HLA antigens predominated and likewise showed a borderline inverse association with PTLD (aOR, 0.58; 95% CI, 0.27-1.24). The FLC levels were less frequently abnormal in cases than controls, but measurements were available for only a subset and confidence intervals were wide (elevated kappa: aOR, 0.57; 95% CI, 0.15-2.12; P = 0.40; elevated lambda: aOR, 0.68; 95% CI, 0.30-1.50; P = 0.34). B cell–activating factor levels were not associated with PTLD.

Conclusions

Our results suggest that circulating DSAs are associated with decreased risk of late-onset PTLD. Because DSAs may develop in the setting of underimmunosuppression, the inverse association with DSAs supports a role for immunosuppression in the etiology of late-onset PTLD.