B-cell activation and lymphoma in patients with HIV

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.

Evaluation of Urinary Free Light Chains as a Marker of Severity of HIV Disease and Its Correlation with CD4 Count: A Pilot Study

Human immunodeficiency virus (HIV) infection weakens immunity. Monitoring the immune status of the patient has become an important aspect of evaluating the progression of the disease and informing follow-up after treatment. Estimation of CD4 counts is quite costly and requires expertise in flow cytometry. In certain pathologies, free light chains (FLCs) are secreted in serum and urine and the magnitude can be used to monitor the severity, progression, and therapeutic monitoring of the disease. Urine as a specimen proves cost-effective and presents reduced risks during sample collection. The stability of light chains in urine at room temperature over extended periods simplifies the management of sample transportation as well. Hence, a pilot cross-sectional study was planned to evaluate the levels of urinary immunoglobulins in patients with HIV. The study was conducted at PGIMER, Dr. Ram Manohar Lohia Hospital (presently ABVIMS), New Delhi. Sixty-nine consecutive ART-naive HIV patients aged between 18 and 40 years and 69 age- and sex-matched healthy controls were included in the study. Urinary FLC kappa (κ) and lambda (λ) were measured using an immunoglobulin ELISA kit. Baseline urinary κ light chain levels were significantly higher in cases when compared with controls (p < .001) and were found to be increased with increasing WHO immunological classes (p < .001) and inversely related to CD4 cell count. However, no significant difference in mean urinary λ immunoglobulin light chain between cases and controls was found and no correlation with CD4 cell count or with stages of WHO immunological classification of HIV disease was observed. It is suggested that urinary free κ chain measurements combined with serum light chain measurements may be a useful marker in the follow-up and monitoring of response to therapies in patients with HIV where testing by flow cytometry is not available.

B cells and atherosclerosis: A HIV perspective

Atherosclerosis remains a leading cause of cardiovascular disease (CVD) globally, with the complex interplay of inflammation and lipid metabolism at its core. Recent evidence suggests a role of B cells in the pathogenesis of atherosclerosis; however, this relationship remains poorly understood, particularly in the context of HIV. We review the multifaceted functions of B cells in atherosclerosis, with a specific focus on HIV. Unique to atherosclerosis is the pivotal role of natural antibodies, particularly those targeting oxidized epitopes abundant in modified lipoproteins and cellular debris. B cells can exert control over cellular immune responses within atherosclerotic arteries through antigen presentation, chemokine production, cytokine production, and cell-cell interactions, actively participating in local and systemic immune responses. We explore how HIV, characterized by chronic immune activation and dysregulation, influences B cells in the context of atherosclerosis, potentially exacerbating CVD risk in persons with HIV. By examining the proatherogenic and antiatherogenic properties of B cells, we aim to deepen our understanding of how B cells influence atherosclerotic plaque development, especially within the framework of HIV. This research provides a foundation for novel B cell-targeted interventions, with the potential to mitigate inflammation-driven cardiovascular events, offering new perspectives on CVD risk management in PLWH.

HIV-1 Structural Proteins or Cell-Signaling Factors? That Is the Question!

The biological activity of structural HIV-1 proteins is not limited to ensuring a productive viral infection but also interferes with cellular homeostasis through intra- and extracellular signaling activation. This interference induces genomic instability, increases the lifespan of the infected cell by inhibiting apoptosis, and subverts cell senescence, resulting in unrestricted cell proliferation. HIV structural proteins are present in a soluble form in the lymphoid tissues and blood of infected individuals, even without active viral replication. The HIV matrix protein p17, the envelope glycoprotein gp120, the transenvelope protein gp41, and the capsid protein p24 interact with immune cells and deregulate the biological activity of the immune system. The biological activity of HIV structural proteins is also demonstrated in endothelial cells and some tumor cell lines, confirming the ability of viral proteins to promote cell proliferation and cancer progression, even in the absence of active viral replication. This review corroborates the hypothesis that HIV structural proteins, by interacting with different cell types, contribute to creating a microenvironment that is favorable to the evolution of cancerous pathologies not classically related to AIDS.

Examining Chronic Inflammation, Immune Metabolism, and T Cell Dysfunction in HIV Infection

Chronic Human Immunodeficiency Virus (HIV) infection remains a significant challenge to global public health. Despite advances in antiretroviral therapy (ART), which has transformed HIV infection from a fatal disease into a manageable chronic condition, a definitive cure remains elusive. One of the key features of HIV infection is chronic immune activation and inflammation, which are strongly associated with, and predictive of, HIV disease progression, even in patients successfully treated with suppressive ART. Chronic inflammation is characterized by persistent inflammation, immune cell metabolic dysregulation, and cellular exhaustion and dysfunction. This review aims to summarize current knowledge of the interplay between chronic inflammation, immune metabolism, and T cell dysfunction in HIV infection, and also discusses the use of humanized mice models to study HIV immune pathogenesis and develop novel therapeutic strategies.

Serum immunoglobulin and the threshold of Fc receptor-mediated immune activation

Antibodies can mediate immune recruitment or clearance of immune complexes through the interaction of their Fc domain with cellular Fc receptors. Clustering of antibodies is a key step in generating sufficient avidity for efficacious receptor recognition. However, Fc receptors may be saturated with prevailing, endogenous serum immunoglobulin and this raises the threshold by which cellular receptors can be productively engaged. Here, we review the factors controlling serum IgG levels in both healthy and disease states, and discuss how the presence of endogenous IgG is encoded into the functional activation thresholds for low- and high-affinity Fc receptors. We discuss the circumstances where antibody engineering can help overcome these physiological limitations of therapeutic antibodies. Finally, we discuss how the pharmacological control of Fc receptor saturation by endogenous IgG is emerging as a feasible mechanism for the enhancement of antibody therapeutics.

A Scoping Review of Vitamin D for Nonskeletal Health: A Framework for Evidence-Based Clinical Practice

BACKGROUND

Low serum 25-hydroxy-vitamin D [25(OH)D] levels are prevalent worldwide. Although the benefits of vitamin D supplementation have focused on skeletal disorders (eg, rickets, osteomalacia, osteoporosis), emerging evidence for nonskeletal health merits further discussion.

PURPOSE

The purpose of this review was to critically examine the vitamin D supplementation literature pertaining to nonskeletal health to help guide clinicians.

METHODS

A scoping review that included observational studies and randomized clinical trials (RCTs) was performed. Evidence from meta-analyses and individual RCTs are discussed, and controversies and future directions are considered.

FINDINGS

25(OH)D deficiency is a ubiquitous condition associated with multiple nonskeletal diseases, including cardiometabolic (heart disease, diabetes, and kidney disease), immune (HIV/AIDS and cancer), lung (from traditional chronic disorders to coronavirus disease 2019), and gut diseases. Vitamin D deficiency also affects health across the life span (children, pregnant, and elderly), mental illness, and reproduction in both men and women. In contrast, vitamin D supplementation does not necessarily improve major medical outcomes, even when low 25(OH)D levels are treated. Screening for 25(OH)D status remains an important practice, primarily for high-risk patients (eg, elderly, women with osteoporosis, people with low exposure to sunlight). It is reasonable to supplement with vitamin D to treat 25(OH)D deficiency, such that if beneficial nonskeletal health occurs, this may be considered as a coadjutant instead of the central tenet of the disease. Furthermore, optimizing dosing regimens is an important clinical consideration.

IMPLICATIONS

Although 25(OH)D deficiency is prevalent in nonskeletal diseases, there is no uniform evidence that vitamin D supplementation improves major medical outcomes, even when low 25(OH)D levels are corrected. Findings from RCTs warrant caution due to possible selection bias. Overall, vitamin D supplementation must be guided by circulating levels as a reasonable medical practice to correct 25(OH)D deficiency.

Follicular CD8+ T Cells Are Elevated in HIV Infection and Induce PD-L1 on B Cells

Follicular CD8+CXCR5+ T cells are a specialized CD8+ T cell subset with unique follicular-homing capabilities that have been reported to display effector functions in viral immunity, tumor immunity, and autoimmunity. CD8+CXCR5+ T cells exhibit B cell helper functions and express CD40L, ICOS, programmed cell death protein 1 (PD-1), and BCL-6, the transcriptional regulator of CD4+CXCR5+ T follicular helper cells and of germinal center B cells. HIV is known to be sequestered in lymphoid follicles, and CD8+CXCR5+ T cell frequency is a marker for disease severity, given that HIV-infected patients with lower numbers of circulating CD8+CXCR5+ T cells display lower CD4+ T cell counts. Likewise, several groups have reported a direct correlation between the quantity of CD8+CXCR5+ T cells and suppression of HIV viral load. In this study, we observed elevated absolute numbers of CD8+CXCR5+ and CD8+CXCR5+BCL-6+PD-1+ T cells in the blood of HIV-infected participants of the Multicenter AIDS Cohort Study. We further demonstrated in vitro that activated human CD8+CXCR5+ T cells isolated from peripheral blood and tonsil from healthy donors show increased CD40L expression and induce the production of PD ligand 1 (PD-L1)+IgG+ B cells. Moreover, absolute numbers of CD8+CXCR5+ T cells significantly and positively correlated with numbers of PD-L1+ B cells found in blood of HIV-infected individuals. Altogether, these results show that activated CD8+CXCR5+ T cells have the ability to activate B cells and increase the percentage of PD-L1+ and PD-L1+IgG+ B cells, which provides insights into the early events of B cell activation and differentiation and may play a role in disease progression and lymphomagenesis in HIV-infected individuals.

The role of viruses in HIV-associated lymphomas

Lymphomas are among the most common cancers in people with HIV (PWH). The lymphoma subtypes and pathogenesis of lymphoma in PWH are different from the immunocompetent population. It is well-known that HIV causes severe CD4+ T cell lymphopenia in the absence of antiretroviral therapy (ART); however, the risk of developing certain subtypes of lymphoma remains elevated even in people receiving ART with preserved CD4+ T cells. HIV contributes to lymphomagenesis and causes decreased immune surveillance via T cell depletion and dysregulation, B cell dysregulation, and the potential contribution of HIV-encoded proteins. The oncogenic gammaherpesviruses, Epstein-Barr virus (EBV) and Kaposi sarcoma herpesvirus (KSHV, also known as human herpesvirus 8), are the causative agents in the majority of HIV-associated lymphomas. HIV-associated T cell depletion and dysregulation allows EBV and KSHV to proliferate in infected B cells. Specific EBV- and KSHV-encoded proteins participate in B cell activation, and proliferation leading to B cell transformation. Understanding the distinct pathogenesis of HIV-associated lymphomas affords opportunities to develop therapies that specifically target these unique aspects and improve lymphoma outcomes in PWH. Agents being studied that target the specific roles of HIV, EBV, and KSHV in lymphomagenesis include immunotherapies, targeted agents, and cellular therapies.

Analysis of Lymphoma-Related Genes with Gene Ontology and Kyoto Encyclopedia of Genes and Genomes Enrichment

Lymphoma is a serious malignant tumor that contains more than 70 different types and seriously endangers the body's lymphatic system. The lymphatic system is the regulatory center of the immune system and is important in the immune response to foreign antigens and tumors. Studies showed that multiple genetic variants are associated with lymphoma but determining the pathogenic mechanisms remains a challenge. In the present study, we first applied the Gene Ontology (GO) and KEGG pathway enrichment analyses of lymphoma-associated and lymphoma-nonassociated genes. Next, the Boruta and max-relevance and min-redundancy feature selection methods were performed to filter and rank features. Then, features preselected and ranked using the incremental feature selection method were applied for the decision tree model to identify the best GO terms and KEGG pathways and extract classification rules. Results indicate that our predicted features, such as B-cell activation, negative regulation of protein processing, negative regulation of mast cell cytokine production, and natural killer cell-mediated cytotoxicity, are associated with the biological process of lymphoma, consistent with those of recent publications. This study provides a new perspective for future research on the molecular mechanisms of lymphoma.

Incidence, Treatment, and Outcome of HIV-Associated Hematologic Malignancies in People Living with HIV in Sweden

People living with HIV (PLHIV) have an increased risk of hematologic malignancies (HMs). We aimed to characterize HMs among PLHIV at Karolinska University Hospital, Stockholm, Sweden. We studied all PLHIV receiving care at our center between 2004 and 2018. Data were retrieved retrospectively from InfCareHIV database and medical records. Around 3,484 patients received HIV care for a total of 22,903 person-years (py) with median follow-up of 7.6 years. HMs were identified in 43 patients with 30 cases of non-Hodgkin lymphoma (NHL), 9 cases of Hodgkin lymphoma (HL), 2 multicentric Castleman's disease, and 1 case each of myeloma and myelodysplastic syndrome. The incidence rate of NHL was 88/10⁵ py and HL 39.6/10⁵ py. The incidence of NHL declined 2004-2010 versus 2011-2018 (180.8 vs. 40.1/10⁵ py; p = .001). Median time from HIV diagnosis to malignancy was shorter in NHL compared with HL (1.2 years vs. 8.9 years; p = .01) and effective HIV treatment was less common in NHL (33% vs. 100%; p < .001). The 5-year survival rate of NHL was 59% and HL 43%, significantly lower compared with lymphoma survival in the general population in Sweden. In the era of effective antiretroviral therapy (ART), the incidence rate of lymphoma was more than five times higher in PLHIV and 5-year survival significantly inferior. Efforts for earlier identification of HIV-infected individuals are likely to affect the incidence of NHL. Additionally, an effective screening for clinical and laboratory signs of HL in PLHIV on ART should be introduced to improve identification and survival of HL in this population.

Key considerations and common adverse events for HIV-positive patients with cancer treated with immune checkpoint inhibitors

HIV-infected patients are more susceptible to cancer due to their immune-compromised condition and HIV infection. Chronic inflammation and immune dysregulation are the main causes of cancer development in these patients. Because of lymphopenia and an immune-compromised condition, most HIV-infected patients with cancer were not considered for cytotoxic therapies, such as chemotherapy and radiotherapy. Immune checkpoint inhibitors (ICIs) have become a game-changer in many cancer types. However, not enough prospective data is available regarding the use of ICIs in HIV-infected patients with cancer. Retrospective data from case reports/series showed that ICIs are safe in HIV-infected patients with cancer.

What to Do for Increasing Cancer Burden on the African Continent? Accelerating Public Health Diagnostics Innovation for Prevention and Early Intervention on Cancers

No other place illustrates the increasing burden of cancer than in Africa and in particular, sub-Saharan Africa. Many of the individuals to be diagnosed with cancer will be in low-resource settings in the future due to, for example, an increase in populations and aging, and high co-morbidity with infections with viruses such as human immunodeficiency virus (HIV) and human papillomavirus (HPV), as well as the presence of infectious agents linked to cancer development. Due to lack of prevention and diagnostic innovation, patients present with advanced cancers, leading to poor survival and increased mortality. HIV infection-associated cancers such as B cell lymphomas, Kaposi's sarcoma, and HPV-associated cancers such as cervical cancer are particularly noteworthy in this context. Recent reports show that a host of other cancers are also associated with viral infection and these include lung, oral cavity, esophageal, and pharyngeal, hepatocellular carcinoma, and anal and vulvar cancers. This article examines the ways in which diagnostic innovation empowered by integrative biology and informed by public health priorities can improve cancer prevention or early intervention in Africa and beyond. In addition, I argue that because diagnostic biomarkers can often overlap with novel therapeutic targets, diagnostics research and development can have broader value for and impact on medical innovation.

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.

Anti-PD-1 and Anti-PD-L1 Monoclonal Antibodies in People Living with HIV and Cancer

PURPOSE OF REVIEW

Immune checkpoint inhibitors targeting the programmed cell death-1 (PD-1) pathway are a class of anti-cancer immunotherapy agents changing treatment paradigms of many cancers that occur at higher rates in people living with HIV (PLWH) than in the general population. However, PLWH have been excluded from most of the initial clinical trials with these agents.

RECENT FINDINGS

Two recent prospective studies of anti-PD-1 agents, along with observational studies and a meta-analysis, have demonstrated acceptable safety in PLWH. Preliminary evidence indicates activity in a range of tumors and across CD4⁺ T cell counts. Safety and preliminary activity data suggest monoclonal antibodies targeting PD-1 or its ligand, PD-L1, are generally appropriate for PLWH and cancers for which there are FDA-approved indications. Ongoing and future trials of anti-PD-1 and anti-PD-L1 therapy alone or in combination for HIV-associated cancers may further improve outcomes for this underserved population.

HIV-associated Burkitt lymphoma

Burkitt lymphoma is a rare and aggressive non-Hodgkin lymphoma with three classifications: endemic, sporadic, and immunodeficiency-related. High-intensity chemotherapeutic regimens have considerably improved overall survival for patients with Burkitt lymphoma. In this Review of HIV-associated Burkitt lymphoma, we summarise expert opinion and provide general recommendations for the treatment of Burkitt lymphoma in patients with HIV on the basis of retrospective and prospective studies, taking into consideration immune status, CD4 cell counts, the presence of systemic disease, and the risk of CNS involvement or relapse. We also discuss the role of rituximab and antiretroviral therapy. We highlight the reasons behind the possible different mechanisms of lymphomagenesis in HIV-associated Burkitt lymphoma and endemic Burkitt lymphoma, which indicate that HIV might have either a direct or indirect oncogenic role in Burkitt lymphoma. We discuss the possible mechanisms by which HIV and HIV proteins could directly contribute to lymphomagenesis. Identifying these mechanisms might lead to the development of therapies that have fewer toxic effects than high-intensity chemotherapeutic regimens.

Contribution of Human Retroviruses to Disease Development-A Focus on the HIV- and HERV-Cancer Relationships and Treatment Strategies

Animal retroviruses are known for their transforming potential, and this is also true for the ones hosted by humans, which have gathered expanding attention as one of the potent causative agents in various disease, including specific cancer types. For instance, Human T Lymphotropic virus (HTLV) is a well-studied class of oncoviruses causing T cell leukemia, while human immunodeficiency virus (HIV) leads to acquired immunodeficiency syndrome (AIDS), which is linked to a series of defining cancers including Kaposi sarcoma, certain types of non-Hodgkin lymphoma, and cervical cancer. Of note, in addition to these "modern" exogenous retroviruses, our genome harbors a staggering number of human endogenous retroviruses (HERVs). HERVs are the genetic remnants of ancient retroviral germline infection of human ancestors and are typically silenced in normal tissues due to inactivating mutations and sequence loss. While some HERV elements have been appropriated and contribute to human physiological functions, others can be reactivated through epigenetic dysregulations to express retroviral elements and promote carcinogenesis. Conversely, HERV replication intermediates or protein products can also serve as intrinsic pathogen-associated molecular patterns that cause the immune system to interpret it as an exogenous infection, thereby stimulating immune responses against tumors. As such, HERVs have also been targeted as a potential internal strategy to sensitize tumor cells for promising immunotherapies. In this review, we discuss the dynamic role of human retroviruses in cancer development, focusing on HIV and HERVs contribution. We also describe potential treatment strategies, including immunotherapeutic targeting of HERVs, inhibiting DNA methylation to expose HERV signatures, and the use of antiretroviral drugs against HIV and HERVs, which can be employed as prospective anti-cancer modalities.

Burkitt and Burkitt-Like Lymphomas: a Systematic Review

PURPOSE OF REVIEW

Burkitt's lymphoma and its leukemic form (Burkitt cell acute lymphoblastic leukemia) are a highly aggressive disease. We review the classification, clinical presentation, histology, cytogenetics, and the treatment of the disease.

RECENT FINDINGS

Burkitt's lymphoma might be associated with tumor lysis syndrome which is a potentially fatal complication that occurs spontaneously or upon initiation of chemotherapy. Major improvements were made in the treatment of pediatric and adults population using short-course dose-intensive chemotherapy regimens, usually 1 week after a prephase induction. Addition of Rituximab to chemotherapy has become a standard of care. Relapsed/refractory disease has a very poor prognosis and the benefit from autologous/allogeneic hematopoietic stem cell transplant remains uncertain. Rituximab-based short-course dose-intensive chemotherapy is the standard of care of Burkitt's lymphoma even in the immunodeficiency-related form.

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.

Two Different Extranodal Lymphomas in an HIV+ Patient: A Case Report and Review of the Literature

Human immune deficiency virus- (HIV-) infected individuals present a higher risk of developing malignancies. Herein, we are presenting an unusual case of an untreated HIV+ patient, who developed two distinct lymphoproliferative disorders in a period of 4 years: a primary cutaneous T-cell lymphoma (PCTCL) and a diffuse large B-cell lymphoma (DLBCL) not otherwise specified (NOS), the latter developed while commencing combined antiretroviral therapy (cART). The two lymphomas also showed peculiar features: PCTCL are rarely described in HIV+ setting and particularly at such a low clinical stage, and the DLBCL showed uncommon cytology, non-GCB phenotype, EBER negativity, and absence of c-MYC translocation, all atypical features in this clinical context. This report not only confirms the increased risk of lymphoma for HIV+ patients and HIV infection being one of the major risk factors for lymphoid disorders but draws the attention on the possible occurrence of unusual features, suggesting that HIV serology should always be investigated in the clinical suspicion of lymphoma.

Elevated numbers of PD-L1 expressing B cells are associated with the development of AIDS-NHL

The risk for non-Hodgkin lymphoma (NHL) is markedly increased in persons living with human immunodeficiency virus (HIV) infection, and remains elevated in those on anti-retroviral therapy (cART). Both the loss of immunoregulation of Epstein-Barr virus (EBV) infected cells, as well as chronic B-cell activation, are believed to contribute to the genesis of AIDS-related NHL (AIDS-NHL). However, the mechanisms that lead to AIDS-NHL have not been completely defined. A subset of B cells that is characterized by the secretion of IL10, as well as the expression of the programmed cell death ligand-1 (PD-L1/CD274), was recently described. These PD-L1+ B cells can exert regulatory function, including the dampening of T-cell activation, by interacting with the program cell death protein (PD1) on target cells. The role of PD-L1+ B cells in the development of AIDS-NHL has not been explored. We assessed B cell PD-L1 expression on B cells preceding AIDS-NHL diagnosis in a nested case-control study of HIV+ subjects who went on to develop AIDS-NHL, as well as HIV+ subjects who did not, using multi-color flow cytometry. Archival frozen viable PBMC were obtained from the UCLA Multicenter AIDS Cohort Study (MACS). It was seen that the number of CD19+CD24++CD38++and CD19+PD-L1+cells was significantly elevated in cases 1-4 years prior to AIDS-NHL diagnosis, compared to controls, raising the possibility that these cells may play a role in the etiology of AIDS-NHL. Interestingly, most PD-L1+ expression on CD19+ cells was seen on CD19+CD24++CD38++ cells. In addition, we showed that HIV can directly induce PD-L1 expression on B cells through interaction of virion-associated CD40L with CD40 on B cells.

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.

Elevated soluble CD23 level indicates increased risk of B cell non-Hodgkin's lymphomas: evidence from a meta-analysis

The aim of the present study was to determine whether circulating soluble CD23 (sCD23) was associated with B cells non-Hodgkin's lymphomas (B-NHL). PubMed, EMBASE, and ISI Web of Science were extensively searched without language restriction. Data was extracted in a standardized data collection sheet after two reviewers scanned studies independently. The association between sCD23 and NHL was indicated as odds ratio (OR) along with its related 95% confidence interval (95% CI). Meta-analysis was conducted via RevMan 5.3. A total of five studies, which included 964 B-NHL patients and 1243 matched controls without B-NHL, among which 257 were HIV-positive donors and 986 were general controls, were included in our study. Meta-analysis revealed a significant association between peripheral sCD23 level and B-NHL in HIV-positive samples (OR 1.66, 95% CI 1.25, 2.20; P = 0.0005) as well as the general population (OR 2.51; 95% CI 1.71, 3.86; P < 0.00001). Meta-analysis, stratified by sampling time prior to diagnosis, indicated potential HIV-NHL patients are 2.34-folds more likely to have higher blood sCD23 level, although this association is statistically meaningful only during 3-5 years prior to diagnosis (95% CI 1.27, 4.33). Subgroup analysis based on B-NHL type demonstrated a significant association between sCD23 level and diffuse large B cell lymphoma (DLBCL), chronic lymphocytic leukemia (CLL), and follicular lymphoma (FL). The findings of our study indicate a positive association of circulating sCD23 level and B-NHL risks and highlight the possibility of sCD23 as a predictive marker of B-NHL. However, to better understand the underlying mechanism, further studies are needed.

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

BACKGROUND

Chronic immune activation is a harbinger of AIDS-associated non-Hodgkin lymphoma (AIDS-NHL), yet the underlying basis is unclear. Microbial translocation, the passage of microbial components from the gastrointestinal tract into the systemic circulation, is a source of systemic immune activation in HIV infection and may be an important contributor to chronic B-cell activation and subsequent AIDS-NHL development.

METHOD

We measured biomarkers of microbial translocation including bacterial receptors/antibodies, intestinal barrier proteins, and macrophage activation-associated cytokines/chemokines, in serum from 200 HIV-infected men from the Multicenter AIDS Cohort Study prior to their AIDS-NHL diagnosis (mean = 3.9 years; SD = 1.6 years) and 200 controls. Controls were HIV-infected men who did not develop AIDS-NHL, individually matched to cases on CD4 T-cell count, prior antiretroviral drug use, and recruitment year into the cohort.

RESULTS

Biomarkers of bacterial translocation and intestinal permeability were significantly increased prior to AIDS-NHL. Lipopolysaccharide-binding protein (LPB), fatty acid-binding protein 2 (FABP2), and soluble CD14 were associated with 1.6-fold, 2.9-fold, and 3.7-fold increases in AIDS-NHL risk for each unit increase on the natural log scale, respectively. Haptoglobin had a 2.1-fold increase and endotoxin-core antibody a 2.0-fold decrease risk for AIDS-NHL (fourth versus first quartile). Biomarkers of macrophage activation were significantly increased prior to AIDS-NHL: B-cell activation factor (BAFF), IL18, monocyote chemoattractant protein-1 (MCP1), tumor necrosis factor-α (TNFα), and CCL17 had 2.2-fold, 2.0-fold, 1.6-fold, 2.8-fold, and 1.7-fold increases in risk for each unit increase on the natural log scale, respectively.

CONCLUSION

These data provide evidence for microbial translocation as a cause of the systemic immune activation in chronic HIV infection preceding AIDS-NHL development.

HIV-Associated Cancers and Related Diseases

Clusters of cases of pneumocystis pneumonia and Kaposi’s sarcoma in New York and California in men who had sex with men were early harbingers of the acquired immunodeficiency syndrome (AIDS) epidemic.1 The syndrome was also soon noted to be associated with a high incidence of aggressive B-cell lymphomas. As the AIDS definition crystallized, Kaposi’s sarcoma, aggressive B-cell lymphomas, and invasive cervical cancer were considered to be AIDS-defining cancers when they developed in patients with human immunodeficiency virus (HIV) infection.2 Additional cancers are now known to be associated with HIV (Table 1 ). The term HIV-associated cancer is used here to describe this larger group of cancers (both AIDS-defining and non–AIDS-defining cancers) that have an increased incidence among patients with HIV infection. In addition, incidental cancers also may develop in patients with HIV infection.

Disease drivers of aging

It has long been known that aging, at both the cellular and organismal levels, contributes to the development and progression of the pathology of many chronic diseases. However, much less research has examined the inverse relationship-the contribution of chronic diseases and their treatments to the progression of aging-related phenotypes. Here, we discuss the impact of three chronic diseases (cancer, HIV/AIDS, and diabetes) and their treatments on aging, putative mechanisms by which these effects are mediated, and the open questions and future research directions required to understand the relationships between these diseases and aging.

Human immunodeficiency virus (HIV) and Epstein-Barr virus (EBV) related lymphomas, pathology view point

The contribution of Epstein Barr virus (EBV) and Kaposi sarcoma herpes virus (KSHV) to the development of specific types of malignant lymphomas occurring in the human immunodeficiency virus (HIV) setting has been extensively studied since the beginning of the HIV epidemic 35 years ago. The introduction of highly active antiretroviral therapies (HAART) in 1996 has changed dramatically the incidence of HIV-related malignancies. Nevertheless, malignant lymphomas continue to be the major group of malignances observed in HIV infected individuals, and the most common cause of cancer related-deaths. Common features of the predominant B-cell lymphomas in the HIV⁺ setting are the frequent plasmacytoid morphology of the neoplastic cells, advanced stage, aggressive disease and frequent extranodal involvement. In this article, we review the evolving concepts and definitions of the various EBV-associated lymphomas in HIV⁺ patients, including diffuse large B-cell lymphoma, Burkitt lymphoma, classical Hodgkin lymphoma, plasmablastic lymphoma and primary effusion lymphoma. The current knowledge regarding the pathogenesis of these malignancies, the interplay between HIV and EBV co-infection in the development of certain HIV related lymphomas, and the emerging paradigm that suggests that HIV may play a direct role in lymphomagenesis are explored as well.

Does persistent HIV replication explain continued lymphoma incidence in the era of effective antiretroviral therapy?

Non-Hodgkin lymphomas are highly increased in incidence in individuals infected with HIV, and this continues to be the case in spite of highly effective combined antiretroviral therapy (cART). New evidence has demonstrated that while successful virtual recovery of CD4 counts and elimination of HIV from peripheral blood can be achieved with cART, viral replication can still occur in lymphoid tissues. In addition, recent studies have suggested that adipose tissue provides an additional reservoir for HIV-infected macrophages and T lymphocytes even in the context of successful cART therapy. In this review article, we discuss possible mechanisms leading to the development of lymphoma in the cART era.

HIV-1-Mediated BAFF Secretion in Macrophages Does Not Require Endosomal TLRs, Type-I IFN, and Nef, but Depends on the Cellular Phenotype Status

HIV-1 infection is characterized by persistent viral replication, chronic immune activation, and CD4(+) T cell depletion. Moreover, several immune dysfunctions are observed in cells that are not targeted by the virus, such as B cells. Some B cell abnormalities include hypergammaglobulinemia, nonspecific B cell activation, class switching, increased cell turnover, breakage of tolerance, and a loss of the capacity to generate and maintain memory. Several cytokines and growth factors that are increased in the serum of HIV-1-infected individuals have been suggested to directly or indirectly trigger B cell activation, and one of these is BAFF. In this study, we investigate the ability of fully competent (R5-tropic) HIV-1 to induce BAFF production by monocyte-derived macrophages (MDMs). We demonstrate here that HIV-1 drives BAFF production in MDMs in a type-I IFN- and TLR-independent manner. Moreover, we determine that HIV-1 Nef accessory protein is dispensable in BAFF upregulation as a nef-deleted HIV-1 strain is still able to increase BAFF at levels similar to the wild type strain. Finally, we show that the macrophage phenotype status affects HIV-1 replication and BAFF induction, as both were abrogated in MDMs displaying a M1 phenotype. This study provides new useful information about the increased levels of BAFF observed during HIV-1 infection and highlights the importance of macrophages as a source of BAFF, a phenomenon that might contribute to B cell dysfunctions at inflammatory tissue sites in infected individuals.

Right iliac fossa lymphoma in an HIV positive patient: A diagnostic dilemma

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An association has been established between HIV and lymphoma.

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Lymphoma can present with non-specific or unusual symptoms.

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Lymphoma can also present in patients with well-controlled HIV.

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Lymphoma in HIV patients is an important differential but is often diagnosed at a late stage in the UK.

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It is important that suspicion of lymphoma is raised in patients with HIV.

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It is important that a multidisciplinary approach to diagnosis is taken early on to allow prompt management of this condition

Lymphoma should be considered early in patients with HIV when there is a history of weight loss. Although B-cell lymphoma is an AIDS-defining cancer, and many reports of lymphoma in HIV positive patients exist in the literature, this case report illustrates that even in patients with well-controlled HIV the diagnosis must be considered, and puts forward an unusual presentation in an otherwise asymptomatic patient.

A 52 year old woman presented for a routine HIV follow-up appointment and was found to be experiencing weight loss. An abdominal examination revealed a right iliac fossa mass. Subsequent CT thorax, abdomen, pelvis imaging confirmed a large mass but did not allow determination of the primary source. Serological tumour marker investigations were unyielding. Trans-vaginal ultrasound guided biopsy of the mass demonstrated diffuse large B-cell lymphoma.

This case report emphasises the importance of having a high index of suspicion for these cancers even in patients with low viral load who are on anti-retroviral treatment. It also demonstrates the importance of taking a multidisciplinary approach to diagnosis of the condition to enable prompt treatment and thus improve the outcome for the patient.

Viral co-infections and paraproteins in HIV: effect on development of hematological malignancies

The role of viral co-infections and paraproteins in the development of hematological malignancies (HMs) in HIV remains unclear. Using our large database of HIV+ patients, we investigated whether co-infection and paraproteinemia increase the risk of HM. Data on demographics, hepatitis B (HBV) and hepatitis C virus (HCV) co-infections, paraproteinemia, HIV characteristics, and biopsy proven malignant hematological disorders for HIV+ patients were collected over a 10-year period in a large urban hospital setting. We identified 10,293 HIV+ patients who were followed for a median duration of 53 months. Of the 10,293 patients with HIV, 229 (2.2 %) were diagnosed with a HM. Over 85 % of patients in both groups were tested; no significant difference in the prevalence of chronic HBV or HCV was noted between the HM positive (n = 229) and HM negative (n = 9992) patients. The serum protein electrophoresis test was performed for 1371 of the 10,221 patients. HM positive patients, compared to HM negative, were more likely to be tested for paraproteins (OR 3.3, 95 % CI 2.5-4.4) and more likely to have a discrete paraprotein band (OR 3.3, 95 % CI 1.2-8.9). Discrete paraproteins exclusively correlated with the development of plasma cell malignancies. Faint or oligoclonal protein bands were seen in high grade B cell lymphomas but did not show a significant correlation with HM development. Chronic hepatitis B or C infections did not correlate with the development of HM in HIV; however, viral influence on host gene transformation may have been impacted by anti-viral therapy limiting the duration of high viremic states.

Role of HIV-1 matrix protein p17 variants in lymphoma pathogenesis

Although in decline after successful anti-HIV therapy, B-cell lymphomas are still elevated in HIV-1-seropositive (HIV+) persons, and the mechanisms are obscure. The HIV-1 matrix protein p17 persists in germinal centers long after HIV-1 drug suppression, and some p17 variants (vp17s) activate Akt signaling and promote growth of transformed B cells. Here we show that vp17s derived from four of five non-Hodgkin lymphoma (NHL) tissues from HIV+ subjects display potent B-cell growth-promoting activity. They are characterized by amino acid insertions at position 117-118 (Ala-Ala) or 125-126 (Gly-Asn or Gly-Gln-Ala-Asn-Gln-Asn) among some other mutations throughout the sequence. Identical dominant vp17s are found in both tumor and plasma. Three of seven plasma samples from an independent set of NHL cases manifested multiple Ala insertions at position 117-118, and one with the Ala-Ala profile also promoted B-cell growth and activated Akt signaling. Ultradeep pyrosequencing showed that vp17s with C-terminal insertions are more frequently detected in plasma of HIV+ subjects with than without NHL. Insertion of Ala-Ala at position 117-118 into reference p17 (refp17) was sufficient to confer B-cell growth-promoting activity. In contrast, refp17 bearing the Gly-Asn insertion at position 125-126 did not, suggesting that mutations not restricted to the C terminus can also account for this activity. Biophysical analysis revealed that the Ala-Ala insertion mutant is destabilized compared with refp17, whereas the Gly-Asn form is stabilized. This finding provides an avenue for further exploration of structure function relationships and new treatment strategies in combating HIV-1-related NHL.

Evolution of the Humoral Response during HCV Infection: Theories on the Origin of Broadly Neutralizing Antibodies and Implications for Vaccine Design

Similar to human immunodeficiency virus (HIV)-1, vaccine-induced elicitation of broadly neutralizing (bNt) antibodies (Abs) is gaining traction as a key goal toward the eradication of the hepatitis C virus (HCV) pandemic. Previously, the significance of the Ab response against HCV was underappreciated given the prevailing evidence advancing the role of the cellular immune response in clearance and overall control of the infection. However, recent findings have driven growing interest in the humoral arm of the immune response and in particular the role of bNt responses due to their ability to confer protective immunity upon passive transfer in animal models. Nevertheless, the origin and development of bNt Abs is poorly understood and their occurrence is rare as well as delayed with emergence only observed in the chronic phase of infection. In this review, we characterize the interplay between the host immune response and HCV as it progresses from the acute to chronic phase of infection. In addition, we place these events in the context of current hypotheses on the origin of bNt Abs against the HIV-1, whose humoral immune response is better characterized. Based on the increasing significance of the humoral immune response against HCV, characterization of these events may be critical in understanding the development of the bNt responses and, thus, provide strategies toward effective vaccine design.

Predictive Value of Cytokines and Immune Activation Biomarkers in AIDS-Related Non-Hodgkin Lymphoma Treated with Rituximab plus Infusional EPOCH (AMC-034 trial)

PURPOSE

The aims of this study were to determine whether pretreatment plasma levels of cytokines and immune activation-associated molecules changed following treatment for AIDS-NHL with rituximab plus infusional EPOCH, and to determine whether pretreatment levels of these molecules were associated with response to treatment and/or survival.

EXPERIMENTAL DESIGN

We quantified plasma levels of B-cell activation-associated molecules (sCD27, sCD30, and sCD23) and cytokines (IL6, IL10, and CXCL13) before and after the initiation of treatment in persons with AIDS-NHL (n = 69) in the AIDS Malignancies Consortium (AMC) 034 study, which evaluated treatment of AIDS-NHL with EPOCH chemotherapy and rituximab.

RESULTS

Treatment resulted in decreased plasma levels of some of these molecules (CXCL13, sCD27, and sCD30), with decreased levels persisting for one year following the completion of treatment. Lower levels of CXCL13 before treatment were associated with complete responses following lymphoma therapy. Elevated levels of IL6 pretreatment were associated with decreased overall survival, whereas higher IL10 levels were associated with shorter progression-free survival (PFS), in multivariate analyses. Furthermore, patients with CXCL13 or IL6 levels higher than the median levels for the NHL group, as well as those who had detectable IL10, had lower overall survival and PFS, in Kaplan-Meier analyses.

CONCLUSIONS

These results indicate that CXCL13, IL6, and IL10 have significant potential as prognostic biomarkers for AIDS-NHL.

Dysregulated B-cell TLR2 expression and elevated regulatory B-cell frequency precede the diagnosis of AIDS-related non-Hodgkin lymphoma

OBJECTIVES

In antiretroviral therapy (ART)-treated patients, to determine if AIDS-related non-Hodgkin lymphoma (AIDS-NHL) is preceded by: elevated frequency of potentially malignant abnormal activated/germinal center-like B cells, elevated serum prevalence of B-cell stimulatory Toll-like receptor (TLR) ligands resulting from HIV infection-associated microbial translocation, dysregulated B-cell TLR expression/signaling, and perturbations in the frequency of immunoregulatory cells.

DESIGN

A case-control study nested with a cohort study of HIV-infected women.

METHODS

Prediagnostic AIDS-NHL cases (n = 12, collected 1-12 months before diagnosis) and controls (n = 42) from the Women's Interagency HIV Study cohort, were matched for HIV and ART status, age, race, and CD4 lymphocyte count. Serum levels of TLR ligands, the prevalence of malignancy-associated abnormal activated/germinal center-like (CD19CD10CD71CD86AID) B cells, TLR2 expression on B cells, expression of TLR2-modulating micro-RNA, and the frequency of regulatory T and B cells were assessed.

RESULTS

Diagnosis of AIDS-NHL was preceded by a significantly elevated frequency of activated/germinal center-like CD19CD10CD71CD86AID B cells (P = 0.0072), elevated serum prevalence of the TLR2 ligand, and significantly elevated B-cell TLR2 expression (P = 0.0015), positively correlating with the frequency of activated/germinal center-like B cells (rho = 0.7273, P = 0.0144). In cases, a purified subset of activated/germinal center-like B cells exhibited decreased expression of microRNAs that modulate TLR2 signaling, including miR-21, 146a, 146b, and 155. Finally, cases also exhibited significantly elevated frequencies of antitumor immunity inhibitory regulatory B cells (P = 0.0024), but not regulatory T cells.

CONCLUSIONS

Our findings suggest that increased microbial translocation and dysregulated TLR expression/signaling, coupled with an elevated frequency of regulatory B cells, precede the diagnosis of AIDS-NHL in HIV-infected ART-treated patients.

How do viruses trick B cells into becoming lymphomas?

PURPOSE OF REVIEW

Since the discovery of Epstein-Barr virus in Burkitt's lymphoma 50  years ago, only one other virus, namely Kaposi's sarcoma-associated herpesvirus/human herpesvirus-8, has been confirmed to be a direct cause of B-cell lymphoma. Here we will review the evidence for Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus as causal lymphoma agents.

RECENT FINDINGS

A deeper understanding of specific mechanisms by which Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus cause B-cell lymphomas has been acquired over the past years, in particular with respect to viral protein interactions with host cell pathways, and microRNA functions. Specific therapies based on knowledge of viral functions are beginning to be evaluated, mostly in preclinical models.

SUMMARY

Understanding the causal associations of specific infectious agents with certain B-cell lymphomas has allowed more accurate diagnosis and classification. A deeper knowledge of the specific mechanisms of transformation is essential to begin assessing whether virus-targeted treatment modalities may be used in the future.

HIV-1-triggered release of type I IFN by plasmacytoid dendritic cells induces BAFF production in monocytes

HIV-1 infection leads to numerous B cell abnormalities, including hypergammaglobulinemia, nonspecific B cell activation, nonspecific class switching, increased cell turnover, breakage of tolerance, increased immature/transitional B cells, B cell malignancies, as well as a loss of capacity to generate and maintain memory, all of which contribute to a global impairment of the immune humoral compartment. Several cytokines and soluble factors, which are increased in sera of HIV-1-infected individuals, have been suggested to directly or indirectly contribute to these B cell dysfunctions, and one of these is the B cell-activating factor (BAFF). We report in this study that HIV-1 (X4- and R5-tropic) upregulates BAFF expression and secretion by human monocytes. Moreover, we show that the virus-mediated production of BAFF by monocytes relies on a type I IFN response by a small percentage of plasmacytoid dendritic cells (pDCs) present in the monocyte cultures. HIV-1-induced type I IFN by pDCs triggers BAFF production in both classical and intermediate monocytes, but not in nonclassical monocytes, which nonetheless display a very strong basal BAFF production. We report also that basal BAFF secretion was higher in monocytes obtained from females compared with those from male donors. This study provides a novel mechanistic explanation for the increased BAFF levels observed during HIV-1 infection and highlights the importance of pDC/monocyte crosstalk to drive BAFF secretion.

Immune Activation: Contribution to AIDS-Associated Non-Hodgkin Lymphoma

HIV infection is associated with a greatly elevated risk for the development of non-Hodgkin lymphoma (NHL), which while diminished, remains elevated in the highly active antiretroviral therapy (HAART) era. Chronic B cell activation, driven by contact with HIV virions, B cell-stimulatory cytokines, viruses (EBV, HPV, HCV), and by high levels of antigenic stimulation occurs in HIV infected persons, and it is seen at even higher levels in those who go on to develop AIDS-NHL. Evidence from multiple studies indicates that elevated serum levels of several B cell-stimulatory cytokines and biomarkers are seen preceding AIDS-NHL, as well as in immunocompetent persons that develop NHL. Phenotypic changes in circulating B cells also are seen preceding AIDS-NHL, including the expression of AICDA, and of cell-surface molecules and miRNA that are associated with activated B cells. HAART only partially normalizes the immune system of treated HIV⁺ persons as they still show clear evidence for ongoing inflammation and immune activation in, even those who show complete suppression of HIV viremia. Together, this provides ample evidence to support the notion that chronic activation of B cells contributes to the genesis of B cell lymphomas.

HIV-1 induces B-cell activation and class switch recombination via spleen tyrosine kinase and c-Jun N-terminal kinase pathways

OBJECTIVE

Patients infected by the HIV type 1 (HIV-1) frequently show a general deregulation of immune system. A direct influence of HIV-1 particles on B-cell activation, proliferation and B-cell phenotype alterations has been recently described. Moreover, expression of activation-induced cytidinedeaminase (AID) mRNA, which is responsible for class switch recombination (CSR) and somatic hypermutation (SHM), was reported to be overexpressed in B cells exposed to HIV-1.

DESIGN

Study of primary human B cells in an in-vitro model.

METHODS

In the current study, we evaluated which signalling pathways are activated in primary B cells after a direct contact with HIV-1 particles in vitro using different kinase inhibitors.

RESULTS

Here, we report that B-cell activation together with the increase of AID mRNA expression and the subsequent class switch recombination (CSR) in HIV-exposed B cells occurred through spleen tyrosine kinase (SYK) and c-Jun N-terminal kinase (JNK) pathways.

CONCLUSION

Therefore, we showed that HIV-1 could directly induce primary B-cell deregulation via SYK/B-cell receptor (BCR) engagement, and that activation was followed by the JNK pathway activation. To our knowledge, these data provide the first evidence that SYK/BCR activation was the first step for B-cell activation and CSR mechanism after HIV-1 stimulation in a T-cell-free context.

CNS demyelinating disorder with mixed features of neuromyelitis optica and multiple sclerosis in HIV-1 infection. Case report and literature review

An African-American male presented with bilateral visual impairment, gait difficulties, and bladder and bowel incontinence raising concerns for multiple sclerosis (MS) or neuromyelitis optica (NMO). He was identified to be HIV-1 infected with high viral load and low CD4+ counts. Magnetic resonance imaging (MRI) of the brain was abnormal, but atypical for MS. MRI of the cervical and thoracic spinal cord showed multiple areas of myelitis with a longitudinally extensive thoracic transverse myelitis that showed enhancement with gadolinium suggestive of NMO. Cerebrospinal fluid showed oligoclonal IgG bands but did not show reactivity to aquaporin 4. Patient underwent treatment for the acute exacerbation with intravenous corticosteroids and treatment of the HIV infection with highly active antiretroviral therapy (HAART). A year later, his viral load was <20 copies/ml and CD4+ counts were normal. Vision did not significantly improve, but his ambulation improved from a near total non-ambulatory state to ambulating without aids and resolution of the bladder and bowel incontinence. A demyelinating disorder of the central nervous system (CNS) like MS or NMO has been previously reported in the context of HIV infection. The remarkable improvement of symptoms has also been previously reported with HAART, and these observations have led to clinical trials of MS with HAART therapy in the absence of HIV infection. We reviewed the few cases of CNS demyelinating disorders with HIV infection reported in the literature and speculate on the mechanisms of pathogenesis.

Fallen angels or risen apes? A tale of the intricate complexities of imbalanced immune responses in the pathogenesis and progression of immune-mediated and viral cancers

Excessive immune responses directed against foreign pathogens, self-antigens, or commensal microflora can cause cancer establishment and progression if the execution of tight immuno-regulatory mechanisms fails. On the other hand, induction of potent tumor antigen-specific immune responses together with stimulation of the innate immune system is a pre-requisite for effective anti-tumor immunity, and if suppressed by the strong immuno-regulatory mechanisms can lead to cancer progression. Therefore, it is crucial that the inevitable co-existence of these fundamental, yet conflicting roles of immune-regulatory cells is carefully streamlined as imbalances can be detrimental to the host. Infection with chronic persistent viruses is characterized by severe immune dysfunction resulting in T cell exhaustion and sometimes deletion of antigen-specific T cells. More often, this is due to increased immuno-regulatory processes, which are triggered to down-regulate immune responses and limit immunopathology. However, such heightened levels of immune disruption cause a concomitant loss of tumor immune-surveillance and create a permissive microenvironment for cancer establishment and progression, as demonstrated by increased incidences of cancer in immunosuppressed hosts. Paradoxically, while some cancers arise as a consequence of increased immuno-regulatory mechanisms that inhibit protective immune responses and impinge on tumor surveillance, other cancers arise due to impaired immuno-regulatory mechanisms and failure to limit pathogenic inflammatory responses. This intricate complexity, where immuno-regulatory cells can be beneficial in certain immune settings but detrimental in other settings underscores the need for carefully formulated interventions to equilibrate the balance between immuno-stimulatory and immuno-regulatory processes.

Serum levels of cytokines and biomarkers for inflammation and immune activation, and HIV-associated non-Hodgkin B-cell lymphoma risk

BACKGROUND

HIV infection is associated with a marked increase in risk for non-Hodgkin lymphoma (AIDS-NHL). However, the mechanisms that promote the development of AIDS-NHL are not fully understood.

METHODS

In this study, serum levels of several cytokines and other molecules associated with immune activation were measured in specimens collected longitudinally during 1 to 5 years preceding AIDS-NHL diagnosis, in 176 AIDS-NHL cases and 176 HIV(+) controls from the Multicenter AIDS Cohort Study (MACS).

RESULTS

Multivariate analyses revealed that serum levels of immunoglobulin free light chains (FLC), interleukin (IL)-6, IL-10, IP-10/CXCL10, neopterin, and TNF-α were elevated in those HIV(+) individuals who went on to develop AIDS-NHL. In addition, the fraction of specimens with detectable IL-2 was increased and the fraction with detectable IL-4 was decreased in these subjects.

CONCLUSIONS

These results suggest that long-term, chronic immune activation, possibly driven by macrophage-produced cytokines, precedes development of NHL in HIV(+) individuals.

IMPACT

FLC, IL-6, IL-10, IP-10/CXCL10, neopterin, and TNF-α may serve as biomarkers for AIDS-NHL. .

Insights into B cells and HIV-specific B-cell responses in HIV-infected individuals

Human immunodeficiency virus (HIV) disease is associated with dysregulation and dysfunction involving all major lymphocyte populations, including B cells. Such perturbations occur early in the course of infection and are driven in large part by immune activation resulting from ongoing HIV replication leading to bystander effects on B cells. While most of the knowledge regarding immune cell abnormalities in HIV-infected individuals has been gained from studies conducted on the peripheral blood, it is clear that the virus is most active and most damaging in lymphoid tissues. Here, we discuss B-cell perturbations in HIV-infected individuals, focusing on the skewing of B-cell subsets that circulate in the peripheral blood and their counterparts that reside in lymphoid tissues. This review also highlights recent advances in evaluating HIV-specific B-cell responses both in the memory B-cell compartment, as well as in circulating antibody-secreting plasmablasts and the more differentiated plasma cells residing in tissues. Finally, we consider how knowledge gained by investigating B cells in HIV-infected individuals may help inform the development of an effective antibody-based HIV vaccine.

TLR2-activated B cells are phenotypically similar to the abnormal circulating B cells seen preceding the diagnosis of AIDS-related NHL diagnosis

BACKGROUND

AIDS-related non-Hodgkin lymphoma (AIDS-NHL) is a common AIDS-defining cancer. Prior studies suggest that chronic B-cell activation precedes AIDS-NHL diagnosis. Activation of B cells by multiple factors, including Toll-like receptor (TLR) signaling, leads to the expression of activation-induced cytidine deaminase (AID), a DNA mutating molecule that can contribute to oncogene translocations/mutations, leading to NHL. The goal of this study was to determine whether surface markers expressed on activated and/or germinal center B cells, and AID expression, were elevated on circulating B cells preceding AIDS-NHL and to determine if TLR signaling contributes to this activated B-cell phenotype.

METHODS

Stored viable peripheral blood mononuclear cell specimens, obtained before AIDS-NHL diagnosis, were assessed by multicolor flow cytometry. Additionally, B cells isolated from peripheral blood mononuclear cell were exposed to TLR ligands in vitro, after which B-cell phenotype was assessed by flow cytometry.

RESULTS

An elevated fraction of B cells expressing CD10, CD71, or CD86 was seen in those who went on to develop AIDS-NHL. AID expression was detected in some who developed AIDS-NHL, but not in HIV+ or HIV- controls. TLR2-stimulated purified B cells exhibited the activated B-cell phenotype observed in HIV+ subjects before AIDS-NHL diagnosis.

CONCLUSIONS

These results indicate that an elevated fraction of B cells display an activated/germinal center phenotype in those HIV+ subjects who go on to develop AIDS-NHL and suggest that TLR2-mediated activation may play a role in HIV infection-associated B-cell activation, potentially contributing to the genesis of AIDS-NHL.

Lymphomas occurring specifically in HIV-infected patients: from pathogenesis to pathology

Lymphomas that develop in HIV positive patients are predominantly aggressive B-cell malignancies. The most common HIV-associated lymphomas are Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL). Lymphomas that occur specifically in HIV positive patients include primary effusion lymphoma (PEL) and its solid variants, plasmablastic lymphoma of the oral cavity type and lymphoma associated with Kaposi sarcoma herpesvirus (KSHV)-related multicentric Castleman disease. These lymphomas, together with BL and immunoblastic lymphoma subtypes with plasmacytoid differentiation, carry Epstein-Barr virus (EBV) infection and display a phenotype related to plasma cells. Globally, EBV is identified in the neoplastic cells of approximately 40% of HIV-associated lymphomas, but the detection of EBV varies considerably with the site of presentation and the histological subtype. EBV infection occurs in 80-100% of primary central nervous system lymphomas and PELs, 80% of DLBCLs with immunoblastic-plasmacytoid features, and 30-50% of BL-plasmacytoid. KSHV is specifically associated with PEL, which usually occurs in a setting of profound immunosuppression. Current knowledge about HIV-associated lymphomas can be summarized as follows: (1) lymphomas specifically occurring in patients with HIV infection are closely linked to other viral diseases; (2) most of these lymphomas exhibit plasmablastic differentiation.

B cell lymphoma in HIV transgenic mice

Background

Human Immunodeficiency Virus Type I (HIV-1) infection is associated with a high incidence of B-cell lymphomas. The role of HIV in these lymphomas is unclear and currently there are no valid in vivo models for better understanding HIV-related lymphomagenesis. Transgenic (Tg) 26 mice have a 7.4-kb pNL4-3 HIV-1 provirus lacking a 3.1-kb sequence encompassing parts of the gag-pol region. Approximately 15% of these HIV Tg mice spontaneously develop lymphoma with hallmark pre-diagnostic markers including skin lesions, diffuse lymphadenopathy and an increase in pro-inflammatory serum cytokines. Here we describe the phenotypic and molecular characteristics of the B cell leukemia/lymphoma in the Tg mice.

Results

The transformed B cell population consists of CD19⁺pre-BCR⁺CD127⁺CD43⁺CD93⁺ precursor B cells. The tumor cells are clonal and characterized by an increased expression of several cellular oncogenes. Expression of B cell-stimulatory cytokines IL-1β, IL-6, IL-10, IL-12_p40, IL-13 and TNFα and HIV proteins p17, gp120 and nef were elevated in the Tg mice with lymphoma.

Conclusions

Increased expression of HIV proteins and the B-cell stimulatory factors is consistent with the interpretation that one or more of these factors play a role in lymphoma development. The lymphomas share many similarities with those occurring in HIV/AIDS⁺ patients and may provide a valuable model for understanding AIDS-related lymphomagenesis and elucidating the role played by HIV-1.

Levels of murine, but not human, CXCL13 are greatly elevated in NOD-SCID mice bearing the AIDS-associated Burkitt lymphoma cell line, 2F7

Currently, few rodent models of AIDS-associated non-Hodgkin’s lymphoma (AIDS-NHL) exist. In these studies, a novel mouse/human xenograft model of AIDS-associated Burkitt lymphoma (AIDS-BL) was created by injecting cells of the human AIDS-BL cell line, 2F7, intraperitoneally into NOD-SCID mice. Mice developed tumors in the peritoneal cavity, with metastases to the spleen, thymus, and mesenteric lymph nodes. Expression of the chemokine receptor, CXCR5, was greatly elevated in vivo on BL tumor cells in this model, as shown by flow cytometry. CXCL13 is the ligand for CXCR5, and serum and ascites levels of murine, but not human, CXCL13 showed a striking elevation in tumor-bearing mice, with levels as high as 200,000 pg/ml in ascites, as measured by ELISA. As shown by immunohistochemistry, murine CXCL13 was associated with macrophage-like tumor-infiltrating cells that appeared to be histiocytes. Blocking CXCR5 on 2F7 cells with neutralizing antibodies prior to injection into the mice substantially delayed tumor formation. The marked elevations in tumor cell CXCR5 expression and in murine CXCL13 levels seen in the model may potentially identify an important link between tumor-interacting histiocytes and tumor cells in AIDS-BL. These results also identify CXCL13 as a potential biomarker for this disease, which is consistent with previous studies showing that serum levels of CXCL13 were elevated in human subjects who developed AIDS-lymphoma. This mouse model may be useful for future studies on the interactions of the innate immune system and AIDS-BL tumor cells, as well as for the assessment of potential tumor biomarkers for this disease.

Serum levels of the chemokine CXCL13, genetic variation in CXCL13 and its receptor CXCR5, and HIV-associated non-hodgkin B-cell lymphoma risk

BACKGROUND

CXCL13 and CXCR5 are a chemokine and receptor pair whose interaction is critical for naïve B-cell trafficking and activation within germinal centers. We sought to determine whether CXCL13 levels are elevated before HIV-associated non-Hodgkin B-cell lymphoma (AIDS-NHL), and whether polymorphisms in CXCL13 or CXCR5 are associated with AIDS-NHL risk and CXCL13 levels in a large cohort of HIV-infected men.

METHODS

CXCL13 levels were measured in sera from 179 AIDS-NHL cases and 179 controls at three time-points. TagSNPs in CXCL13 (n = 16) and CXCR5 (n = 11) were genotyped in 183 AIDS-NHL cases and 533 controls. OR and 95% confidence intervals (CI) for the associations between one unit increase in log CXCL13 levels and AIDS-NHL, as well as tagSNP genotypes and AIDS-NHL, were computed using logistic regression. Mixed linear regression was used to estimate mean ratios (MR) for the association between tagSNPs and CXCL13 levels.

RESULTS

CXCL13 levels were elevated for more than 3 years (OR = 3.24; 95% CI = 1.90-5.54), 1 to 3 years (OR = 3.39; 95% CI = 1.94-5.94), and 0 to 1 year (OR = 3.94; 95% CI = 1.98-7.81) before an AIDS-NHL diagnosis. The minor allele of CXCL13 rs355689 was associated with reduced AIDS-NHL risk (OR(TCvsTT) = 0.65; 95% CI = 0.45-0.96) and reduced CXCL13 levels (MR(CCvsTT) = 0.82; 95% CI = 0.68-0.99). The minor allele of CXCR5 rs630923 was associated with increased CXCL13 levels (MR(AAvsTT) = 2.40; 95% CI = 1.43-4.50).

CONCLUSIONS

CXCL13 levels were elevated preceding an AIDS-NHL diagnosis, genetic variation in CXCL13 may contribute to AIDS-NHL risk, and CXCL13 levels may be associated with genetic variation in CXCL13 and CXCR5.

IMPACT

CXCL13 may serve as a biomarker for early AIDS-NHL detection.