Type I interferon responses in rhesus macaques prevent SIV infection and slow disease progression.

Inflammation in HIV infection is predictive of non-AIDS morbidity and death, higher set point plasma virus load and virus acquisition; thus, therapeutic agents are in development to reduce its causes and consequences. However, inflammation may simultaneously confer both detrimental and beneficial effects. This dichotomy is particularly applicable to type I interferons (IFN-I) which, while contributing to innate control of infection, also provide target cells for the virus during acute infection, impair CD4 T-cell recovery, and are associated with disease progression. Here we manipulated IFN-I signalling in rhesus macaques (Macaca mulatta) during simian immunodeficiency virus (SIV) transmission and acute infection with two complementary in vivo interventions. We show that blockade of the IFN-I receptor caused reduced antiviral gene expression, increased SIV reservoir size and accelerated CD4 T-cell depletion with progression to AIDS despite decreased T-cell activation. In contrast, IFN-α2a administration initially upregulated expression of antiviral genes and prevented systemic infection. However, continued IFN-α2a treatment induced IFN-I desensitization and decreased antiviral gene expression, enabling infection with increased SIV reservoir size and accelerated CD4 T-cell loss. Thus, the timing of IFN-induced innate responses in acute SIV infection profoundly affects overall disease course and outweighs the detrimental consequences of increased immune activation. Yet, the clinical consequences of manipulation of IFN signalling are difficult to predict in vivo and therapeutic interventions in human studies should be approached with caution.

Initiation of ART during early acute HIV infection preserves mucosal Th17 function and reverses HIV-related immune activation.

Mucosal Th17 cells play an important role in maintaining gut epithelium integrity and thus prevent microbial translocation. Chronic HIV infection is characterized by mucosal Th17 cell depletion, microbial translocation and subsequent immune-activation, which remain elevated despite antiretroviral therapy (ART) correlating with increased mortality. However, when Th17 depletion occurs following HIV infection is unknown. We analyzed mucosal Th17 cells in 42 acute HIV infection (AHI) subjects (Fiebig (F) stage I-V) with a median duration of infection of 16 days and the short-term impact of early initiation of ART. Th17 cells were defined as IL-17+ CD4+ T cells and their function was assessed by the co-expression of IL-22, IL-2 and IFNγ. While intact during FI/II, depletion of mucosal Th17 cell numbers and function was observed during FIII correlating with local and systemic markers of immune-activation. ART initiated at FI/II prevented loss of Th17 cell numbers and function, while initiation at FIII restored Th17 cell numbers but not their polyfunctionality. Furthermore, early initiation of ART in FI/II fully reversed the initially observed mucosal and systemic immune-activation. In contrast, patients treated later during AHI maintained elevated mucosal and systemic CD8+ T-cell activation post initiation of ART. These data support a loss of Th17 cells at early stages of acute HIV infection, and highlight that studies of ART initiation during early AHI should be further explored to assess the underlying mechanism of mucosal Th17 function preservation.

Sevelamer does not decrease lipopolysaccharide or soluble CD14 levels but decreases soluble tissue factor, low-density lipoprotein (LDL) cholesterol, and oxidized LDL cholesterol levels in individuals with untreated HIV infection.

UNLABELLED: Abnormal levels of inflammation are associated with cardiovascular disease and mortality in human immunodeficiency virus (HIV)-infected patients. Microbial translocation, which may cause inflammation, is decreased by sevelamer in patients undergoing hemodialysis. In this single-arm study, we evaluated the effects of 8 weeks of sevelamer therapy on 36 HIV-infected subjects who were not receiving antiretroviral therapy. Sevelamer did not significantly change markers of microbial translocation, inflammation, or T-cell activation. During sevelamer treatment, however, levels of soluble tissue factor, low-density lipoprotein (LDL) cholesterol, and oxidized LDL cholesterol decreased significantly, whereas D-dimer levels increased. Thus, in this study population, sevelamer did not reduce microbial translocation but may have yielded cardiovascular benefits. CLINICAL TRIALS REGISTRATION: NCT 01543958.

Characteristics of congenital hepatic fibrosis in a large cohort of patients with autosomal recessive polycystic kidney disease.

BACKGROUND & AIMS: Autosomal recessive polycystic kidney disease (ARPKD), the most common ciliopathy of childhood, is characterized by congenital hepatic fibrosis and progressive cystic degeneration of kidneys. We aimed to describe congenital hepatic fibrosis in patients with ARPKD, confirmed by detection of mutations in PKHD1. METHODS: Patients with ARPKD and congenital hepatic fibrosis were evaluated at the National Institutes of Health from 2003 to 2009. We analyzed clinical, molecular, and imaging data from 73 patients (age, 1-56 years; average, 12.7 ± 13.1 years) with kidney and liver involvement (based on clinical, imaging, or biopsy analyses) and mutations in PKHD1. RESULTS: Initial symptoms were liver related in 26% of patients, and others presented with kidney disease. One patient underwent liver and kidney transplantation, and 10 others received kidney transplants. Four presented with cholangitis and one with variceal bleeding. Sixty-nine percent of patients had enlarged left lobes on magnetic resonance imaging, 92% had increased liver echogenicity on ultrasonography, and 65% had splenomegaly. Splenomegaly started early in life; 60% of children younger than 5 years had enlarged spleens. Spleen volume had an inverse correlation with platelet count and prothrombin time but not with serum albumin level. Platelet count was the best predictor of spleen volume (area under the curve of 0.88905), and spleen length corrected for patient's height correlated inversely with platelet count (R(2) = 0.42, P < .0001). Spleen volume did not correlate with renal function or type of PKHD1 mutation. Twenty-two of 31 patients who underwent endoscopy were found to have varices. Five had variceal bleeding, and 2 had portosystemic shunts. Forty-percent had Caroli syndrome, and 30% had an isolated dilated common bile duct. CONCLUSIONS: Platelet count is the best predictor of the severity of portal hypertension, which has early onset but is underdiagnosed in patients with ARPKD. Seventy percent of patients with ARPKD have biliary abnormalities. Kidney and liver disease are independent, and variability in severity is not explainable by type of PKHD1 mutation; ClinicalTrials.gov number, NCT00068224.

Suppressed Th17 levels correlate with elevated PIAS3, SHP2, and SOCS3 expression in CD4 T cells during acute simian immunodeficiency virus infection.

T helper 17 (Th17) cells play an important role in mucosal immune homeostasis and maintaining the integrity of the mucosal epithelial barrier. Loss of Th17 cells has been extensively documented during human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) infections. The lack of effective repopulation of Th17 cells has been associated with chronic immune activation mediated by the translocation of microbial products. Using ex vivo analysis of purified peripheral blood CD4 T cells from SIV-infected rhesus macaques, we show that the suppression of interleukin-17 (IL-17) expression correlated with upregulated expression of negative regulatory genes PIAS3, SHP2, and SOCS3 in CD4 T cells. Suppressed Th17 expression was accompanied by elevated levels of soluble CD14 (sCD14) and lipopolysaccharide binding protein (LBP) in the plasma during early stages of infection. Plasma viral loads rather than sCD14 or LBP levels correlated with acute immune activation. Additionally, we observed a significant increase in the expression of CD14 on peripheral blood monocytes that correlated with IL-23 expression and markers of microbial translocation. Taken together, our results provide new insights into the early events associated with acute SIV pathogenesis and suggest additional mechanisms playing a role in suppression of Th17 cells.

Loss of a tyrosine-dependent trafficking motif in the simian immunodeficiency virus envelope cytoplasmic tail spares mucosal CD4 cells but does not prevent disease progression.

A hallmark of pathogenic simian immunodeficiency virus (SIV) and human immunodeficiency virus (HIV) infections is the rapid and near-complete depletion of mucosal CD4(+) T lymphocytes from the gastrointestinal tract. Loss of these cells and disruption of epithelial barrier function are associated with microbial translocation, which has been proposed to drive chronic systemic immune activation and disease progression. Here, we evaluate in rhesus macaques a novel attenuated variant of pathogenic SIVmac239, termed ΔGY, which contains a deletion of a Tyr and a proximal Gly from a highly conserved YxxØ trafficking motif in the envelope cytoplasmic tail. Compared to SIVmac239, ΔGY established a comparable acute peak of viremia but only transiently infected lamina propria and caused little or no acute depletion of mucosal CD4(+) T cells and no detectable microbial translocation. Nonetheless, these animals developed T-cell activation and declining peripheral blood CD4(+) T cells and ultimately progressed with clinical or pathological features of AIDS. ΔGY-infected animals also showed no infection of macrophages or central nervous system tissues even in late-stage disease. Although the ΔGY mutation persisted, novel mutations evolved, including the formation of new YxxØ motifs in two of four animals. These findings indicate that disruption of this trafficking motif by the ΔGY mutation leads to a striking alteration in anatomic distribution of virus with sparing of lamina propria and a lack of microbial translocation. Because these animals exhibited wild-type levels of acute viremia and immune activation, our findings indicate that these pathological events are dissociable and that immune activation unrelated to gut damage can be sufficient for the development of AIDS.

An autoinflammatory disease with deficiency of the interleukin-1-receptor antagonist.

BACKGROUND: Autoinflammatory diseases manifest inflammation without evidence of infection, high-titer autoantibodies, or autoreactive T cells. We report a disorder caused by mutations of IL1RN, which encodes the interleukin-1-receptor antagonist, with prominent involvement of skin and bone. METHODS: We studied nine children from six families who had neonatal onset of sterile multifocal osteomyelitis, periostitis, and pustulosis. Response to empirical treatment with the recombinant interleukin-1-receptor antagonist anakinra in the first patient prompted us to test for the presence of mutations and changes in proteins and their function in interleukin-1-pathway genes including IL1RN. RESULTS: We identified homozygous mutations of IL1RN in nine affected children, from one family from Newfoundland, Canada, three families from The Netherlands, and one consanguineous family from Lebanon. A nonconsanguineous patient from Puerto Rico was homozygous for a genomic deletion that includes IL1RN and five other interleukin-1-family members. At least three of the mutations are founder mutations; heterozygous carriers were asymptomatic, with no cytokine abnormalities in vitro. The IL1RN mutations resulted in a truncated protein that is not secreted, thereby rendering cells hyperresponsive to interleukin-1beta stimulation. Patients treated with anakinra responded rapidly. CONCLUSIONS: We propose the term deficiency of the interleukin-1-receptor antagonist, or DIRA, to denote this autosomal recessive autoinflammatory disease caused by mutations affecting IL1RN. The absence of interleukin-1-receptor antagonist allows unopposed action of interleukin-1, resulting in life-threatening systemic inflammation with skin and bone involvement. (ClinicalTrials.gov number, NCT00059748.)

Host response to translocated microbial products predicts outcomes of patients with HBV or HCV infection.

BACKGROUND & AIMS: Chronic infection with hepatitis B or C virus (HBV or HCV) is a leading cause of cirrhosis by unknown mechanisms of pathogenesis. Translocation of gut microbial products into the systemic circulation might increase because of increased intestinal permeability, bacterial overgrowth, or impaired clearance of microbial products by Kupffer cells. We investigated whether the extent and progression of liver disease in patients with chronic HBV or HCV infection are associated with microbial translocation and subsequent activation of monocytes. METHODS: In a retrospective study, we analyzed data from 16 patients with minimal fibrosis, 68 with cirrhosis, and 67 uninfected volunteers. We analyzed plasma levels of soluble CD14 (sCD14), intestinal fatty acid binding protein, and interleukin-6 by enzyme-linked immunosorbent assay, and lipopolysaccharide (LPS) by the limulus amebocyte lysate assay, at presentation and after antiviral treatment. RESULTS: Compared with uninfected individuals, HCV- and HBV-infected individuals had higher plasma levels of LPS, intestinal fatty acid binding protein (indicating enterocyte death), sCD14 (produced upon LPS activation of monocytes), and interleukin-6. Portal hypertension, indicated by low platelet counts, was associated with enterocyte death (P=.045 at presentation, P<.0001 after therapy). Levels of sCD14 correlated with markers of hepatic inflammation (P=.02 for aspartate aminotransferase, P=.002 for ferritin) and fibrosis (P<.0001 for γ-glutamyl transpeptidase, P=.01 for alkaline phosphatase, P<.0001 for α-fetoprotein). Compared to subjects with minimal fibrosis, subjects with severe fibrosis at presentation had higher plasma levels of sCD14 (P=.01) and more hepatic CD14+ cells (P=.0002); each increased risk for disease progression (P=.0009 and P=.005, respectively). CONCLUSIONS: LPS-induced local and systemic inflammation is associated with cirrhosis and predicts progression to end-stage liver disease in patients with HBV or HCV infection.

Hypomorphic Rag mutations can cause destructive midline granulomatous disease.

Destructive midline granulomatous disease characterized by necrotizing granulomas of the head and neck is most commonly caused by Wegener granulomatosis, natural killer/T-cell lymphomas, cocaine abuse, or infections. An adolescent patient with myasthenia gravis treated with thymectomy subsequently developed extensive granulomatous destruction of midface structures, palate, nasal septum, airways, and epiglottis. His lymphocyte numbers, total immunoglobulin G level, and T-cell receptor (TCR) repertoire appeared normal. Sequencing of Recombination activating gene-1 (Rag1) showed compound heterozygous Rag1 mutations; a novel deletion with no recombinase activity and a missense mutation resulting in 50% Rag activity. His thymus was dysplastic and, although not depleted of T cells, showed a notable absence of autoimmune regulator (AIRE) and Foxp3(+) regulatory T cells. This distinct Rag-deficient phenotype characterized by immune dysregulation with granulomatous hyperinflammation and autoimmunity, with relatively normal T and B lymphocyte numbers and a diverse TCR repertoire expands the spectrum of presentation in Rag deficiency. This study was registered at www.clinicaltrials.gov as #NCT00128973.

Cytopenia and leukocyte recovery shape cytokine fluctuations after myeloablative allogeneic hematopoietic stem cell transplantation.

BACKGROUND: Allogeneic hematopoietic stem cell transplantation is associated with profound changes in levels of various cytokines. Emphasis has been placed on conditioning-associated mucosal damage and neutropenia and associated bacterial translocation as the initiating conditions predisposing to acute graft-versus-host disease. The post-transplant period is, however, also associated with increases in certain homeostatic cytokines. It is unclear how much the homeostatic drive to lymphocyte recovery and the production of cytokines from the engrafting donor immune system determine cytokine fluctuations in the peri- and immediate post-transplant period. The aim of this study was to examine the contributions of the conditioning regimen, donor engraftment, infections, and graft-versus-host disease to fluctuations in cytokines involved in homeostasis and inflammation. DESIGN AND METHODS: We examined the levels of 33 cytokines in relation to peri- and post-transplant events such as conditioning regimen, chimerism, and acute graft-versus-host disease in myeloablative, non-T cell-replete HLA-identical sibling donor stem cell transplantation for hematologic malignancies. RESULTS: We identified two cytokine storms. The first occurred following conditioning and reached peak levels when all the leukocytes were at their lowest concentrations. The second cytokine storm occurred concurrently with hematopoietic reconstitution and subsided with the achievement of full donor lymphocyte chimerism. CONCLUSIONS: Our results indicate that both recipient-related and donor-related factors contribute to the changes in cytokine levels in the recipient following allogeneic hematopoietic stem cell transplantation. The study reported here was performed using plasma samples drawn from patients enrolled in the ClinicalTrials.gov-registered trials NCT00467961 and NCT00378534.

Plasma levels of soluble CD14 independently predict mortality in HIV infection.

BACKGROUND: Chronic human immunodeficiency virus (HIV) infection is associated with intestinal permeability and microbial translocation that contributes to systemic immune activation, which is an independent predictor of HIV disease progression. The association of microbial translocation with clinical outcome remains unknown. METHODS: This nested case-control study included 74 subjects who died, 120 of whom developed cardiovascular disease and 81 of whom developed AIDS during the Strategies for Management of Anti-Retroviral Therapy (SMART) study with matched control subjects. Intestinal fatty acid binding protein (I-FABP), lipopolysaccharide (LPS), soluble CD14 (sCD14), endotoxin core antibody (EndoCAb), and 16S ribosomal DNA (rDNA) were measured in baseline plasma samples. RESULTS: Subjects with the highest quartile of sCD14 levels had a 6-fold higher risk of death than did those in the lowest quartile (95% confidence interval, 2.2-16.1; P<.001), with minimal change after adjustment for inflammatory markers, CD4(+) T cell count, and HIV RNA level. No other marker was significantly associated with clinical outcomes. I-FABP, LPS, and sCD14 were increased and EndoCAb was decreased in study subjects, compared with healthy volunteers. sCD14 level correlated with levels of IL-6, C-reactive protein, serum amyloid A and D-dimer. CONCLUSIONS: sCD14, a marker of monocyte response to LPS, is an independent predictor of mortality in HIV infection. Therapeutic attenuation of innate immune activation may improve survival in patients with HIV infection.

Can early therapy reduce inflammation?

PURPOSE OF REVIEW: Serious non-AIDS events or noninfectious complications of HIV infection far outnumber AIDS events in the current combination antiretroviral therapy (ART) era and are attributed to chronic inflammation. Thus, a better understanding of why inflammation persists on ART will assist in developing better therapeutic strategies, including optimal timing of ART initiation. RECENT FINDINGS: Markers of inflammation and coagulation, such as D-dimer, interleukin-6, C-reactive protein, soluble CD14, and soluble CD163, predict end-organ disease and mortality, whereas markers of T-cell activation appear more predictive of CD4 T-cell decline, AIDS events, or response to therapy. Initiating ART at high CD4 T-cell counts can result in less inflammation as supported by studies in acute and early HIV infection, but antiretroviral drugs may differentially affect inflammatory pathways. Decreasing inflammation in HIV-uninfected individuals may decrease morbidity, but long-term outcomes studies in HIV-infected individuals are lacking. SUMMARY: Circulating biomarkers of inflammation are among the strongest predictors of non-AIDS outcomes in treated HIV infection. With additional investigation, they may serve in the future as specific end-organ disease surrogate endpoints and may help identify those patients at highest risk of non-AIDS events who may benefit from either early ART and/or potential adjuvant anti-inflammatory therapies.

Study design issues in evaluating immune biomarkers.

PURPOSE OF REVIEW: The dramatic increase in the number and type of immune biomarkers that can be measured, particularly those assessing immune activation, has led to numerous investigations in HIV-infected individuals to explore pathogenesis and to assess therapeutic interventions that aim to attenuate immune activation. An overview is provided on study designs and related statistical and operational issues relevant to these investigations. RECENT FINDINGS: Cohort studies and nested case-control studies within these cohorts have identified multiple biomarkers that are associated with an increased risk of disease. Early-stage clinical trials of therapies to address these risks in HIV-infected individuals with viral suppression on antiretroviral therapy are a substantial focus of current HIV research. SUMMARY: Appropriate study design is essential in biomarker research.

Neither microbial translocation nor TLR responsiveness are likely explanations for preexisting immune activation in women who subsequently acquired HIV in CAPRISA 004.

Innate immune activation was a strong predictor of HIV acquisition in women at risk for HIV in CAPRISA 004. Identifying the cause(s) of activation could enable targeted prevention interventions. In this study, plasma concentrations of lipopolysaccharide, soluble CD14, and intestinal fatty acid-binding protein did not differ between subjects who did or did not subsequently acquire HIV nor were these levels correlated with plasma cytokines or natural killer cell activation. There was no difference between HIV acquirers and non-acquirers in the chemokine and cytokine responses of peripheral blood mononuclear cells stimulated with TLR2, 4, or 7/8 agonists. Further studies are required.

Oral serum-derived bovine immunoglobulin improves duodenal immune reconstitution and absorption function in patients with HIV enteropathy.

OBJECTIVES: To examine the impact of serum-derived bovine immunoglobulin, an oral medical food known to neutralize bacterial antigen and reduce intestinal inflammation, on restoration of mucosal immunity and gastrointestinal function in individuals with HIV enteropathy. DESIGN: Open-label trial with intensive 8-week phase of bovine serum immunoglobulin (SBI) 2.5 g twice daily with a 4-week washout period and an optional 9-month extension study. METHODS: HIV enteropathy was defined as chronic gastrointestinal symptoms including frequent loose or watery stools despite no identifiable, reversible cause. Upper endoscopy for tissue immunofluorescent antibody assay and disaccharide gut permeability/absorption studies were performed before and after 8 weeks of SBI to test mucosal immunity and gastrointestinal function. Blood was collected for markers of microbial translocation, inflammation, and collagen kinetics. A validated gastrointestinal questionnaire assessed changes in symptoms. RESULTS: All eight participants experienced profound improvement in symptoms with reduced bowel movements/day (P = 0.008) and improvements in stool consistency (P = 0.008). Gut permeability was normal before and after the intervention, but D-xylose absorption increased in seven of eight participants. Mucosal CD4 lymphocyte densities increased by a median of 139.5 cells/mm2 from 213 to 322 cells/mm2 (P = 0.016). Intestinal-fatty acid binding protein (I-FABP), a marker of enterocyte damage, initially rose in seven of eight participants after 8 weeks (P = 0.039), and then fell below baseline in four of five who continued receiving SBI (P = 0.12). Baseline serum I-FABP levels were negatively correlated with subsequent rise in mucosal CD4 lymphocyte densities (r = -0.74, P = 0.046). CONCLUSION: SBI significantly increases intestinal mucosal CD4 lymphocyte counts, improves duodenal function, and showed evidence of promoting intestinal repair in the setting of HIV enteropathy.

Safety and tolerability of a live oral Salmonella typhimurium vaccine candidate in SIV-infected nonhuman primates.

Nontyphoidal Salmonella (NTS) serovars are a common cause of acute food-borne gastroenteritis worldwide and can cause invasive systemic disease in young infants, the elderly, and immunocompromised hosts, accompanied by high case fatality. Vaccination against invasive NTS disease is warranted where the disease incidence and mortality are high and multidrug resistance is prevalent, as in sub-Saharan Africa. Live-attenuated vaccines that mimic natural infection constitute one strategy to elicit protection. However, they must particularly be shown to be adequately attenuated for consideration of immunocompromised subjects. Accordingly, we examined the safety and tolerability of an oral live attenuated Salmonella typhimurium vaccine candidate, CVD 1921, in an established chronic simian immunodeficiency virus (SIV)-infected rhesus macaque model. We evaluated clinical parameters, histopathology, and measured differences in mucosal permeability to wild-type and vaccine strains. Compared to the wild-type S. typhimurium strain I77 in both SIV-infected and SIV-uninfected nonhuman primate hosts, this live-attenuated vaccine shows reduced shedding and systemic spread, exhibits limited pathological disease manifestations in the digestive tract, and induces low levels of cellular infiltration in tissues. Furthermore, wild-type S. typhimurium induces increased intestinal epithelial damage and permeability, with infiltration of neutrophils and macrophages in both SIV-infected and SIV-uninfected nonhuman primates compared to the vaccine strain. Based on shedding, systemic spread, and histopathology, the live-attenuated S. typhimurium strain CVD 1921 appears to be safe and well-tolerated in the nonhuman primate model, including chronically SIV-infected rhesus macaques.

Microbial translocation in HIV infection: causes, consequences and treatment opportunities.

Systemic immune activation is increased in HIV-infected individuals, even in the setting of virus suppression with antiretroviral therapy. Although numerous factors may contribute, microbial products have recently emerged as potential drivers of this immune activation. In this Review, we describe the intestinal damage that occurs in HIV infection, the evidence for translocation of microbial products into the systemic circulation and the pathways by which these products activate the immune system. We also discuss novel therapies that disrupt the translocation of microbial products and the downstream effects of microbial translocation.

CD4 T follicular helper cell dynamics during SIV infection.

CD4 T follicular helper (TFH) cells interact with and stimulate the generation of antigen-specific B cells. TFH cell interaction with B cells correlates with production of SIV-specific immunoglobulins. However, the fate of TFH cells and their participation in SIV-induced antibody production is not well understood. We investigated the phenotype, function, location, and molecular signature of TFH cells in rhesus macaques. Similar to their human counterparts, TFH cells in rhesus macaques represented a heterogeneous population with respect to cytokine function. In a highly differentiated subpopulation of TFH cells, characterized by CD150lo expression, production of Th1 cytokines was compromised while IL-4 production was augmented, and cells exhibited decreased survival, cycling, and trafficking capacity. TFH cells exhibited a distinct gene profile that was markedly altered by SIV infection. TFH cells were infected by SIV; yet, in some animals, these cells actually accumulated during chronic SIV infection. Generalized immune activation and increased IL-6 production helped drive TFH differentiation during SIV infection. Accumulation of TFH cells was associated with increased frequency of activated germinal center B cells and SIV-specific antibodies. Therefore, chronic SIV does not disturb the ability of TFH cells to help B cell maturation and production of SIV-specific immunoglobulins.

Comparative transcriptomics of extreme phenotypes of human HIV-1 infection and SIV infection in sooty mangabey and rhesus macaque.

High levels of HIV-1 replication during the chronic phase of infection usually correlate with rapid progression to severe immunodeficiency. However, a minority of highly viremic individuals remains asymptomatic and maintains high CD4⁺ T cell counts. This tolerant profile is poorly understood and reminiscent of the widely studied nonprogressive disease model of SIV infection in natural hosts. Here, we identify transcriptome differences between rapid progressors (RPs) and viremic nonprogressors (VNPs) and highlight several genes relevant for the understanding of HIV-1-induced immunosuppression. RPs were characterized by a specific transcriptome profile of CD4⁺ and CD8⁺ T cells similar to that observed in pathogenic SIV-infected rhesus macaques. In contrast, VNPs exhibited lower expression of interferon-stimulated genes and shared a common gene regulation profile with nonpathogenic SIV-infected sooty mangabeys. A short list of genes associated with VNP, including CASP1, CD38, LAG3, TNFSF13B, SOCS1, and EEF1D, showed significant correlation with time to disease progression when evaluated in an independent set of CD4⁺ T cell expression data. This work characterizes 2 minimally studied clinical patterns of progression to AIDS, whose analysis may inform our understanding of HIV pathogenesis.

Th17 cells, Job's syndrome and HIV: opportunities for bacterial and fungal infections.

PURPOSE OF REVIEW: Patients with hyper IgE syndrome (HIES) share with HIV patients a predisposition to infections, including candidiasis in autosomal dominant HIES (AD-HIES) and molluscum contagiosum and other viral infections in other disorders of elevated IgE with infectious predilections. This review highlights the underlying pathogenesis of these diseases and their relevance to HIV infection. RECENT FINDINGS: Patients with mutations in STAT3, who lack Th17 cells, develop AD-HIES, whereas other disorders of elevated IgE may be caused by mutations in Tyk2 or DOCK8, the latter of which is associated with decreased expansion of CD8 more so than CD4 T cells. Recent studies on patients with recurrent mucocutaneous candidiasis have led to the discovery of mutations in CARD9 and DECTIN-1, genes key to the production of the Th17-driving cytokines IL-1beta, IL-6, and IL-23. Studies of the peripheral blood of HIV-positive patients have shown a decreased Th17:Th1 ratio, and Th17 cells were preferentially depleted from the gastrointestinal tract within weeks of simian immunodeficiency virus infection in rhesus macaques. SUMMARY: The consequences of inadequate Th17 production in primary immunodeficiency syndromes illustrate the role of Th17 cells in controlling pathogens to which HIV-positive individuals are susceptible. Further understanding of the pathogenesis of opportunistic disease in HIV infection will probably require exploring the role of Th17 cells.