HIV-1 evades virus-specific IgG2 and IgA responses by targeting systemic and intestinal B cells via long-range intercellular conduits.

Contact-dependent communication between immune cells generates protection but also facilitates viral spread. Here we found that macrophages formed long-range actin-propelled conduits in response to negative factor (Nef), a human immunodeficiency virus type 1 (HIV-1) protein with immunosuppressive functions. Conduits attenuated immunoglobulin G2 (IgG2) and IgA class switching in systemic and intestinal lymphoid follicles by shuttling Nef from infected macrophages to B cells through a guanine-exchange factor-dependent pathway involving the amino-terminal anchor, central core and carboxy-terminal flexible loop of Nef. By showing stronger virus-specific IgG2 and IgA responses in patients with Nef-deficient virions, our data suggest that HIV-1 exploits intercellular 'highways' as a 'Trojan horse' to deliver Nef to B cells and evade humoral immunity systemically and at mucosal sites of entry.

Essential Role of Patient Blood Management in a Pandemic: A Call for Action.

The World Health Organization (WHO) has declared coronavirus disease 2019 (COVID-19), the disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a pandemic. Global health care now faces unprecedented challenges with widespread and rapid human-to-human transmission of SARS-CoV-2 and high morbidity and mortality with COVID-19 worldwide. Across the world, medical care is hampered by a critical shortage of not only hand sanitizers, personal protective equipment, ventilators, and hospital beds, but also impediments to the blood supply. Blood donation centers in many areas around the globe have mostly closed. Donors, practicing social distancing, some either with illness or undergoing self-quarantine, are quickly diminishing. Drastic public health initiatives have focused on containment and "flattening the curve" while invaluable resources are being depleted. In some countries, the point has been reached at which the demand for such resources, including donor blood, outstrips the supply. Questions as to the safety of blood persist. Although it does not appear very likely that the virus can be transmitted through allogeneic blood transfusion, this still remains to be fully determined. As options dwindle, we must enact regional and national shortage plans worldwide and more vitally disseminate the knowledge of and immediately implement patient blood management (PBM). PBM is an evidence-based bundle of care to optimize medical and surgical patient outcomes by clinically managing and preserving a patient's own blood. This multinational and diverse group of authors issue this "Call to Action" underscoring "The Essential Role of Patient Blood Management in the Management of Pandemics" and urging all stakeholders and providers to implement the practical and commonsense principles of PBM and its multiprofessional and multimodality approaches.

D-immunized blood donors who are female and who possess at least one HLA-DRB1*15 allele show a propensity for high serum RhIG production.

BACKGROUND: D- individuals with previous D-incompatible pregnancies and/or blood transfusions, as well as those who are actively immunized with small-volume D+ red blood cells (RBCs), are stimulated to produce RhIG. Many factors could influence the stimulation of immunoglobulin production in response to foreign antigen (such as antigen immunogenicity and genetic factors), and it is unknown whether genetic markers could potentially identify responder anti-D donors. STUDY DESIGN AND METHODS: Anti-D donors were assigned a responder profile based on their serum RhIG levels (n = 431). A subset of donors (n = 272) had DNA extracted for polymerase chain reaction genotyping assays for target genes in antigen presentation and pathogen recognition receptors (TLR2, TLR4, CD14, FcγRIIA, and the MHC Class II locus HLA-DRB1). Statistical tests for associations between anti-D donor responder profiles and genetic factors were performed. RESULTS: A large proportion of our donors (38.7%) were classified as nonresponder donors, despite receiving multiple D+ RBC immunizations, whereas female sex was significantly associated with an all-responder profile (p < 0.001). The presence of the DRB1*15 allele and absence of the DRB1*04 allele were more likely to be associated with a responder anti-D donor, although not significantly after Bonferroni correction. A combination of the DRB1*15 allele and female sex was significantly associated with an anti-D donor responder profile. CONCLUSION: This study has identified female sex and the HLA-DRB1*15 allele as potentially useful markers that could be used to screen donors before entry into D immunization programs.

Preservation of functionality, immunophenotype, and recovery of HIV RNA from PBMCs cryopreserved for more than 20 years.

Background: Many research laboratories have long-term repositories of cryopreserved peripheral blood mononuclear cells (PBMC), which are costly to maintain but are of uncertain utility for immunological studies after decades in storage. This study investigated preservation of cell surface phenotypes and in-vitro functional capacity of PBMC from viraemic HIV+ patients and healthy seronegative control subjects, after more than 20 years of cryopreservation. Methods: PBMC were assessed by 18-colour flow cytometry for major lymphocyte subsets within T, B, NK, and dendritic cells and monocytes. Markers of T-cell differentiation and activation were compared with original immunophenotyping performed in 1995/1996 on fresh blood at the time of collection. Functionality of PBMC was assessed by culture with influenza antigen or polyclonal T-cell activation, to measure upregulation of activation-induced CD25 and CD134 (OX40) on CD4 T cells and cytokine production at day 2, and proliferative CD25+ CD4 blasts at day 7. RNA was extracted from cultures containing proliferating CD4+ blast cells, and intracellular HIV RNA was measured using short amplicons for both the Double R and pol region pi code assays, whereas long 4-kbp amplicons were sequenced. Results: All major lymphocyte and T-cell subpopulations were conserved after long-term cryostorage, except for decreased proportions of activated CD38+HLA-DR+ CD4 and CD8 T cells in PBMC from HIV+ patients. Otherwise, differences in T-cell subpopulations between recent and long-term cryopreserved PBMC primarily reflected donor age-associated or HIV infection-associated effects on phenotypes. Proportions of naïve, memory, and effector subsets of T cells from thawed PBMC correlated with results from the original flow cytometric analysis of respective fresh blood samples. Antigen-specific and polyclonal T-cell responses were readily detected in cryopreserved PBMC from HIV+ patients and healthy control donors. Intracellular HIV RNA quantitation by pi code assay correlated with original plasma viral RNA load results. Full-length intracellular and supernatant-derived amplicons were generated from 5/12 donors, and sequences were ≥80% wild-type, consistent with replication competence. Conclusions: This unique study provides strong rationale and validity for using well-maintained biorepositories to support immunovirological research even decades after collection.

Effect of flow change on brain injury during an experimental model of differential hypoxaemia in cardiogenic shock supported by extracorporeal membrane oxygenation.

Differential hypoxaemia (DH) is common in patients supported by femoral veno-arterial extracorporeal membrane oxygenation (V-A ECMO) and can cause cerebral hypoxaemia. To date, no models have studied the direct impact of flow on cerebral damage. We investigated the impact of V-A ECMO flow on brain injury in an ovine model of DH. After inducing severe cardiorespiratory failure and providing ECMO support, we randomised six sheep into two groups: low flow (LF) in which ECMO was set at 2.5 L min-1 ensuring that the brain was entirely perfused by the native heart and lungs, and high flow (HF) in which ECMO was set at 4.5 L min-1 ensuring that the brain was at least partially perfused by ECMO. We used invasive (oxygenation tension-PbTO2, and cerebral microdialysis) and non-invasive (near infrared spectroscopy-NIRS) neuromonitoring, and euthanised animals after five hours for histological analysis. Cerebral oxygenation was significantly improved in the HF group as shown by higher PbTO2 levels (+ 215% vs - 58%, p = 0.043) and NIRS (67 ± 5% vs 49 ± 4%, p = 0.003). The HF group showed significantly less severe brain injury than the LF group in terms of neuronal shrinkage, congestion and perivascular oedema (p < 0.0001). Cerebral microdialysis values in the LF group all reached the pathological thresholds, even though no statistical difference was found between the two groups. Differential hypoxaemia can lead to cerebral damage after only a few hours and mandates a thorough neuromonitoring of patients. An increase in ECMO flow was an effective strategy to reduce such damages.

Recovery of organ-specific tissue oxygen delivery at restrictive transfusion thresholds after fluid treatment in ovine haemorrhagic shock.

BACKGROUND: Fluid resuscitation is the standard treatment to restore circulating blood volume and pressure after massive haemorrhage and shock. Packed red blood cells (PRBC) are transfused to restore haemoglobin levels. Restoration of microcirculatory flow and tissue oxygen delivery is critical for organ and patient survival, but these parameters are infrequently measured. Patient Blood Management is a multidisciplinary approach to manage and conserve a patient's own blood, directing treatment options based on broad clinical assessment beyond haemoglobin alone, for which tissue perfusion and oxygenation could be useful. Our aim was to assess utility of non-invasive tissue-specific measures to compare PRBC transfusion with novel crystalloid treatments for haemorrhagic shock. METHODS: A model of severe haemorrhagic shock was developed in an intensive care setting, with controlled haemorrhage in sheep according to pressure (mean arterial pressure 30-40 mmHg) and oxygen debt (lactate > 4 mM) targets. We compared PRBC transfusion to fluid resuscitation with either PlasmaLyte or a novel crystalloid. Efficacy was assessed according to recovery of haemodynamic parameters and non-invasive measures of sublingual microcirculatory flow, regional tissue oxygen saturation, repayment of oxygen debt (arterial lactate), and a panel of inflammatory and organ function markers. Invasive measurements of tissue perfusion, oxygen tension and lactate levels were performed in brain, kidney, liver, and skeletal muscle. Outcomes were assessed during 4 h treatment and post-mortem, and analysed by one- and two-way ANOVA. RESULTS: Each treatment restored haemodynamic and tissue oxygen delivery parameters equivalently (p > 0.05), despite haemodilution after crystalloid infusion to haemoglobin concentrations below 70 g/L (p < 0.001). Recovery of vital organ-specific perfusion and oxygen tension commenced shortly before non-invasive measures improved. Lactate declined in all tissues and correlated with arterial lactate levels (p < 0.0001). The novel crystalloid supported rapid peripheral vasodilation (p = 0.014) and tended to achieve tissue oxygen delivery targets earlier. PRBC supported earlier renal oxygen delivery (p = 0.012) but delayed peripheral perfusion (p = 0.034). CONCLUSIONS: Crystalloids supported vital organ oxygen delivery after massive haemorrhage, despite haemodilution to < 70 g/L, confirming that restrictive transfusion thresholds are appropriate to support oxygen delivery. Non-invasive tissue perfusion and oximetry technologies merit further clinical appraisal to guide treatment for massive haemorrhage in the context of Patient Blood Management.

Genome-wide analysis of primary CD4+ and CD8+ T cell transcriptomes shows evidence for a network of enriched pathways associated with HIV disease.

BACKGROUND: HIV preferentially infects CD4+ T cells, and the functional impairment and numerical decline of CD4+ and CD8+ T cells characterize HIV disease. The numerical decline of CD4+ and CD8+ T cells affects the optimal ratio between the two cell types necessary for immune regulation. Therefore, this work aimed to define the genomic basis of HIV interactions with the cellular transcriptome of both CD4+ and CD8+ T cells. RESULTS: Genome-wide transcriptomes of primary CD4+ and CD8+ T cells from HIV+ patients were analyzed at different stages of HIV disease using Illumina microarray. For each cell subset, pairwise comparisons were performed and differentially expressed (DE) genes were identified (fold change >2 and B-statistic >0) followed by quantitative PCR validation. Gene ontology (GO) analysis of DE genes revealed enriched categories of complement activation, actin filament, proteasome core and proton-transporting ATPase complex. By gene set enrichment analysis (GSEA), a network of enriched pathways functionally connected by mitochondria was identified in both T cell subsets as a transcriptional signature of HIV disease progression. These pathways ranged from metabolism and energy production (TCA cycle and OXPHOS) to mitochondria meditated cell apoptosis and cell cycle dysregulation. The most unique and significant feature of our work was that the non-progressing status in HIV+ long-term non-progressors was associated with MAPK, WNT, and AKT pathways contributing to cell survival and anti-viral responses. CONCLUSIONS: These data offer new comparative insights into HIV disease progression from the aspect of HIV-host interactions at the transcriptomic level, which will facilitate the understanding of the genetic basis of transcriptomic interaction of HIV in vivo and how HIV subverts the human gene machinery at the individual cell type level.

High levels of human antigen-specific CD4+ T cells in peripheral blood revealed by stimulated coexpression of CD25 and CD134 (OX40).

Ag-specific human CD4(+) memory T lymphocytes have mostly been studied using assays of proliferation in vitro. Intracellular cytokine and ELISPOT assays quantify effector cell populations but barely detect responses to certain recall Ags that elicit strong proliferative responses, e.g., tetanus toxoid, that comprise non-Th1 CD4(+) cells. We have found that culturing whole blood with Ag for 40-48 h induces specific CD4(+) T cells to simultaneously express CD25 and CD134. This new technique readily detects responses to well-described CD4(+) T cell recall Ags, including preparations of mycobacteria, CMV, HSV-1, influenza, tetanus toxoid, Candida albicans, and streptokinase, as well as HIV-1 peptides, with high specificity. The assay detects much higher levels of Ag-specific cells than intracellular cytokine assays, plus the cells retain viability and can be sorted for in vitro expansion. Furthermore, current in vitro assays for human CD4(+) memory T lymphocytes are too labor-intensive and difficult to standardize for routine diagnostic laboratories, whereas the whole-blood CD25(+)CD134(+) assay combines simplicity of setup with a straightforward cell surface flow cytometry readout. In addition to revealing the true extent of Ag-specific human CD4(+) memory T lymphocytes, its greatest use will be as a simple in vitro monitor of CD4(+) T cell responses to Ags such as tuberculosis infection or vaccines.

An Ovine Model of Hemorrhagic Shock and Resuscitation, to Assess Recovery of Tissue Oxygen Delivery and Oxygen Debt, and Inform Patient Blood Management.

BACKGROUND: Aggressive fluid or blood component transfusion for severe hemorrhagic shock may restore macrocirculatory parameters, but not always improve microcirculatory perfusion and tissue oxygen delivery. We established an ovine model of hemorrhagic shock to systematically assess tissue oxygen delivery and repayment of oxygen debt; appropriate outcomes to guide Patient Blood Management. METHODS: Female Dorset-cross sheep were anesthetized, intubated, and subjected to comprehensive macrohemodynamic, regional tissue oxygen saturation (StO2), sublingual capillary imaging, and arterial lactate monitoring confirmed by invasive organ-specific microvascular perfusion, oxygen pressure, and lactate/pyruvate levels in brain, kidney, liver, and skeletal muscle. Shock was induced by stepwise withdrawal of venous blood until MAP was 30 mm Hg, mixed venous oxygen saturation (SvO2) < 60%, and arterial lactate >4 mM. Resuscitation with PlasmaLyte® was dosed to achieve MAP > 65 mm Hg. RESULTS: Hemorrhage impacted primary outcomes between baseline and development of shock: MAP 89 ±â€Š5 to 31 ±â€Š5 mm Hg (P < 0.01), SvO2 70 ±â€Š7 to 23 ±â€Š8% (P < 0.05), cerebral regional tissue StO2 77 ±â€Š11 to 65 ±â€Š9% (P < 0.01), peripheral muscle StO2 66 ±â€Š8 to 16 ±â€Š9% (P < 0.01), arterial lactate 1.5 ±â€Š1.0 to 5.1 ±â€Š0.8 mM (P < 0.01), and base excess 1.1 ±â€Š2.2 to -3.6 ±â€Š1.7 mM (P < 0.05). Invasive organ-specific monitoring confirmed reduced tissue oxygen delivery; oxygen tension decreased and lactate increased in all tissues, but moderately in brain. Blood volume replacement with PlasmaLyte® improved primary outcome measures toward baseline, confirmed by organ-specific measures, despite hemoglobin reduced from baseline 10.8 ±â€Š1.2 to 5.9 ±â€Š1.1 g/dL post-resuscitation (P < 0.01). CONCLUSION: Non-invasive measures of tissue oxygen delivery and oxygen debt repayment are suitable outcomes to inform Patient Blood Management of hemorrhagic shock, translatable for pre-clinical assessment of novel resuscitation strategies.

Mapping the extent of heterogeneity of human CCR5+ CD4+ T cells in peripheral blood and lymph nodes.

BACKGROUND: CD4 T cells that express the chemokine receptor, CCR5, are the most important target of HIV-1 infection, but their functions, phenotypes and anatomical locations are poorly understood. We aimed to use multiparameter flow cytometry to better define the full breadth of these cells. METHODS: High-parameter fluorescence flow and mass cytometry were optimized to analyse subsets of CCR5 memory CD4 T cells, including CD25CD127 Tregs, CXCR3CCR6- Th1-like, CCR6CD161CXCR3- Th17-like, integrins α4ß7 gut-homing, CCR4 skin-homing, CD62L lymph node-homing, CD38HLA-DR activated cells, and CD27-CD28- cytotoxic T lymphocytes, in a total of 22 samples of peripheral blood, ultrasound-guided fine needle biopsies of lymph nodes and excised tonsils. CCR5 antigen-specific CD4 T cells were studied using the OX40 flow-based assay. RESULTS: 10-20% of CCR5 memory CD4 T cells were Tregs, 10-30% were gut-homing, 10-30% were skin-homing, 20-40% were lymph node-homing, 20-50% were Th1-like and 20-40% were Th17-like cells. Up to 30% were cytotoxic T lymphocytes in CMV-seropositive donors, including cells that were either CCR5Granzyme K or CCR5Granzyme B. When all possible phenotypes were exhaustively analysed, more than 150 different functional and trafficking subsets of CCR5 CD4 T cells were seen. Moreover, a small population of resident CD69Granzyme KCCR5 CD4 T cells was found in lymphoid tissues. CMV- and Mycobacterium tuberculosis-specific CD4 T cells were predominantly CCR5. CONCLUSION: These results reveal for the first time the prodigious heterogeneity of function and trafficking of CCR5 CD4 T cells in blood and in lymphoid tissue, with significant implications for rational approaches to prophylaxis for HIV-1 infection and for purging of the HIV-1 reservoir in those participants already infected.

Boosting of Markers of Fcγ Receptor Function in Anti-HIV Antibodies During Structured Treatment Interruption.

Anti-HIV envelope (Env) antibodies elicit important Fc receptor functions, including FcγRIIIa-mediated natural killer cell killing of opsonized infected targets. How these antibodies evolve during HIV infection and treatment remains poorly understood. We describe changes in anti-HIV Env IgG using longitudinal samples from seroconverter subjects treated soon after infection and later during periods of structured treatment interruption (STI). Our well-validated dimeric rsFcγR binding assays combine effects of opsonizing antibody subclasses, epitopes, and geometries to provide a measure of FcγR (Fcγ receptor)-mediated functionality. IgG1 anti-Env titers diminished rapidly during antiretroviral therapy (ART; t1/2 3.0 ± 0.8 months), while the dimeric rsFcγRIIIa activity persisted longer (t1/2 33 ± 11 months), suggesting that there is maintenance of functional antibody specificities within the diminished pool of anti-HIV Env Abs. The initial antibody response to infection in two subjects was characterized by approximately fivefold higher FcγRIIIa compared with FcγRIIa binding activity. Uncoupling of FcγRIIa and FcγRIIIa activities may be a distinct feature of the early antibody response that preferentially engages FcγRIIIa-mediated effector functions. Two to three STI cycles, even with low viremia, were sufficient to boost dimeric FcγR activity in these seroconverter subjects. We hypothesize that increased humoral immunity induced by STI is a desirable functional outcome potentially achievable by therapeutic immunization during ART. We conclude that controlled viral antigen exposure under the protection of suppressive ART may be effective in eliciting FcγR-dependent function in support of viral reactivation and kill strategies.

Possible clearance of transfusion-acquired nef/LTR-deleted attenuated HIV-1 infection by an elite controller with CCR5 Δ32 heterozygous and HLA-B57 genotype.

BACKGROUND: Subject C135 is one of the members of the Sydney Blood Bank Cohort, infected in 1981 through transfusion with attenuated nef/3' long terminal repeat (LTR)-deleted HIV-1, and has maintained undetectable plasma viral load and steady CD4 cell count, in the absence of therapy. Uniquely, C135 combines five factors separately associated with control of viraemia: nef/LTR-deleted HIV-1, HLA-B57, HLA-DR13, heterozygous CCR5 Δ32 genotype and vigorous p24-stimulated peripheral blood mononuclear cell (PBMC) proliferation. Therefore, we studied in detail viral burden and immunological responses in this individual. METHODS: PBMC and gut and lymph node biopsy samples were analysed for proviral HIV-1 DNA by real-time and nested PCRs, and nef/LTR alleles by nested PCR. HIV-specific antibodies were studied by Western blotting, and CD4+ and CD8+ T lymphocyte responses were measured by proliferation and cytokine production in vitro. RESULTS: PBMC samples from 1996, but not since, showed amplification of nef alleles with gross deletions. Infectious HIV-1 was never recovered. Proviral HIV-1 DNA was not detected in recent PBMC or gut or lymph node biopsy samples. C135 has a consistently weak antibody response and a substantial CD4+ T cell proliferative response to a previously described HLA-DR13-restricted epitope of HIV-1 p24 in vitro, which augmented a CD8+ T cell response to an immunodominant HLA-B57-restricted epitope of p24, while his T cells show reduced levels of CCR5. CONCLUSIONS: Subject C135's early PCR and weak antibody results are consistent with limited infection with a poorly replicating nef/LTR-deleted strain of HIV-1. With his HLA-B57-restricted gag-specific CD8 and helper HLA-DR13-restricted CD4 T cell proliferative responses, C135 appears to have cleared his HIV-1 infection 37 years after transfusion.

Longitudinal microarray analysis of cell surface antigens on peripheral blood mononuclear cells from HIV+ individuals on highly active antiretroviral therapy.

BACKGROUND: The efficacy of highly active antiretroviral therapy (HAART) determined by simultaneous monitoring over 100 cell-surface antigens overtime has not been attempted. We used an antibody microarray to analyze changes in the expression of 135 different cell-surface antigens overtime on PBMC from HIV+ patients on HAART. Two groups were chosen, one (n = 6) achieved sustainable response by maintaining below detectable plasma viremia and the other (n = 6) responded intermittently. Blood samples were collected over an average of 3 years and 5-8 time points were selected for microarray assay and statistical analysis. RESULTS: Significant trends over time were observed for the expression of 7 cell surface antigens (CD2, CD3epsilon, CD5, CD95, CD36, CD27 and CD28) for combined patient groups. Between groups, expression levels of 10 cell surface antigens (CD11a, CD29, CD38, CD45RO, CD52, CD56, CD57, CD62E, CD64 and CD33) were found to be differential. Expression levels of CD9, CD11a, CD27, CD28 and CD52, CD44, CD49d, CD49e, CD11c strongly correlated with CD4+ and CD8+ T cell counts, respectively. CONCLUSION: Our findings not only detected markers that may have potential prognostic/diagnostic values in evaluating HAART efficacy, but also showed how density of cell surface antigens could be efficiently exploited in an array-like manner in relation to HAART and HIV-infection. The antigens identified in this study should be further investigated by other methods such as flow cytometry for confirmation as biological analysis of these antigens may help further clarify their role during HAART and HIV infection.

Mechanisms of HIV non-progression; robust and sustained CD4+ T-cell proliferative responses to p24 antigen correlate with control of viraemia and lack of disease progression after long-term transfusion-acquired HIV-1 infection.

BACKGROUND: Elite non-progressors (plasma viral load < 50 copies/ml while antiretroviral naive) constitute a tiny fraction of HIV-infected individuals. After 12 years follow-up of a cohort of 13 long-term non-progressors (LTNP) identified from 135 individuals with transfusion-acquired HIV infection, 5 remained LTNP after 23 to 26 years infection, but only 3 retained elite LTNP status. We examined the mechanisms that differentiated delayed progressors from LTNP in this cohort. RESULTS: A survival advantage was conferred on 12 of 13 subjects, who had at least one host genetic factor (HLA, chemokine receptor or TLR polymorphisms) or viral attenuating factor (defective nef) associated with slow progression. However, antiviral immune responses differentiated the course of disease into and beyond the second decade of infection. A stable p24-specific proliferative response was associated with control of viraemia and retention of non-progressor status, but this p24 response was absent or declined in viraemic subjects. Strong Gag-dominant cytotoxic T lymphocyte (CTL) responses were identified in most LTNP, or Pol dominant-CTL in those with nef-defective HIV infection. CTL were associated with control of viraemia when combined with p24 proliferative responses. However, CTL did not prevent late disease progression. Individuals with sustained viral suppression had CTL recognising numerous Gag epitopes, while strong but restricted responses to one or two immunodominant epitopes was effective for some time, but failed to contain viraemia over the course of this study. Viral escape mutants at a HLA B27-restricted Gag-p24 epitope were detected in only 1 of 3 individuals, whereas declining or negative p24 proliferative responses occurred in all 3 concurrent with an increase in viraemia. CONCLUSION: Detectable viraemia at study entry was predictive of loss of LTNP status and/or disease progression in 6 of 8, and differentiated slow progressors from elite LTNP who retained potent virological control. Sustained immunological suppression of viraemia was independently associated with preserved p24 proliferative responses, regardless of the strength and breadth of the CTL response. A decline in this protective p24 response preceded or correlated with loss of non-progressor status and/or signs of disease progression.

Antibody microarray analysis of cell surface antigens on CD4+ and CD8+ T cells from HIV+ individuals correlates with disease stages.

BACKGROUND: Expression levels of cell surface antigens such as CD38 and HLA-DR are related to HIV disease stages. To date, the immunophenotyping of cell surface antigens relies on flow cytometry, allowing estimation of 3-6 markers at a time. The recently described DotScan antibody microarray technology enables the simultaneous analysis of a large number of cell surface antigens. This new technology provides new opportunities to identify novel differential markers expressed or co-expressed on CD4+ and CD8+ T cells, which could aid in defining the stage of evolution of HIV infection and the immune status of the patient. RESULTS: Using this new technology, we compared cell surface antigen expression on purified CD4+ and CD8+ T cells between 3 HIV disease groups (long-term non-progressors controlling viremia naturally; HIV+ patients on highly active antiretroviral therapy (HAART) with HIV plasma viral loads <50 copies/ml; and HIV+ patients with viremia during HAART) and uninfected controls. Pairwise comparisons identified 17 statistically differential cell surface antigens including 5 novel ones (CD212b1, CD218a, CD183, CD3 epsilon and CD9), not previously reported. Notably, changes in activation marker expression were more pronounced in CD8+ T cells, whereas changes in the expression of cell membrane receptors for cytokines and chemokines were more pronounced in CD4+ T cells. CONCLUSION: Our study not only confirmed cell surface antigens previously reported to be related to HIV disease stages, but also identified 5 novel ones. Of these five, three markers point to major changes in responsiveness to certain cytokines, which are involved in Th1 responses. For the first time our study shows how density of cell surface antigens could be efficiently exploited in an array manner in relation to HIV disease stages. This new platform of identifying disease markers can be further extended to study other diseases.

Pathogenicity and immunogenicity of attenuated, nef-deleted HIV-1 strains in vivo.

In efforts to develop an effective vaccine, sterilizing immunity to primate lentiviruses has only been achieved by the use of live attenuated viruses carrying major deletions in nef and other accessory genes. Although live attenuated HIV vaccines are unlikely to be developed due to a myriad of safety concerns, opportunities exist to better understand the correlates of immune protection against HIV infection by studying rare cohorts of long-term survivors infected with attenuated, nef-deleted HIV strains such as the Sydney blood bank cohort (SBBC). Here, we review studies of viral evolution, pathogenicity, and immune responses to HIV infection in SBBC members. The studies show that potent, broadly neutralizing anti-HIV antibodies and robust CD8+ T-cell responses to HIV infection were not necessary for long-term control of HIV infection in a subset of SBBC members, and were not sufficient to prevent HIV sequence evolution, augmentation of pathogenicity and eventual progression of HIV infection in another subset. However, a persistent T-helper proliferative response to HIV p24 antigen was associated with long-term control of infection. Together, these results underscore the importance of the host in the eventual outcome of infection. Thus, whilst generating an effective antibody and CD8+ T-cell response are an essential component of vaccines aimed at preventing primary HIV infection, T-helper responses may be important in the generation of an effective therapeutic vaccine aimed at blunting chronic HIV infection.

First Evidence for the Disease-Stage, Cell-Type, and Virus Specificity of microRNAs during Human Immunodeficiency Virus Type-1 Infection.

The potential involvement of host microRNAs (miRNAs) in HIV infection is well documented, and evidence suggests that HIV modulates and also dysregulates host miRNAs involved in maintaining the host innate immune system. Moreover, the dysregulation of host miRNAs by HIV also effectively interferes directly with the host gene expression. In this study, we have simultaneously evaluated the expression of host miRNAs in both CD4+ and CD8+ T-cells derived from HIV-positive (HIV+) individuals (viremic and aviremic individuals while receiving highly active antiretroviral therapy (HAART), therapy-naïve long-term non-progressors (LTNP), and HIV-negative (HIV-) healthy controls. miRNAs were run on Affymetrix V2 chips, and the differential expression between HIV+ and HIV- samples, along with intergroup comparisons, was derived using PARTEK software, using an FDR of 5% and an adjusted p-value < 0.05. The miR-199a-5p was found to be HIV-specific and expressed in all HIV+ groups as opposed to HIV- controls. Moreover, these are the first studies to reveal clearly the highly discriminatory miRNAs at the level of the disease state, cell type, and HIV-specific miRNAs.

Immunomodulation of inflammatory leukocyte markers during intravenous immunoglobulin treatment associated with clinical efficacy in chronic inflammatory demyelinating polyradiculoneuropathy.

OBJECTIVE: The objective of the study was to profile leukocyte markers modulated during intravenous immunoglobulin (IVIg) treatment, and to identify markers and immune pathways associated with clinical efficacy of IVIg for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with potential for monitoring treatment efficacy. METHODS: Response to IVIg treatment in newly diagnosed IVIg-naïve and established IVIg-experienced patients was assessed by changes in expression of inflammatory leukocyte markers by flow cytometry. The adjusted INCAT disability and Medical Research Council sum scores defined clinical response. RESULTS: Intravenous immunoglobulin modulated immunopathogenic pathways associated with inflammatory disease in CIDP. Leukocyte markers of clinical efficacy included reduced CD185+ follicular helper T cells, increased regulatory markers (CD23 and CD72) on B cells, and reduction in the circulating inflammatory CD16+ myeloid dendritic cell (mDC) population and concomitant increase in CD62L and CD195 defining a less inflammatory lymphoid homing mDC phenotype. A decline in inflammatory CD16+ dendritic cells was associated with clinical improvement or stability, and correlated with magnitude of improvement in neurological assessment scores, but did not predict relapse. IVIg also induced a nonspecific improvement in regulatory and reduced inflammatory markers not associated with clinical response. CONCLUSIONS: Clinically effective IVIg modulated inflammatory and regulatory pathways associated with ongoing control or resolution of CIDP disease. Some of these markers have potential for monitoring outcome.

Identification of genetic polymorphisms that predict responder/non-responder profiles to the RhD antigen.

BACKGROUND: Regular plasma donors who produce high titre anti-D immunoglobulin (Ig) are overseen by the Australian Red Cross Blood Service RhD Program. New donors to the program are immunised with small amounts of RhD-positive RBCs, whilst donors who have developed anti-D due to previous RhD-incompatible blood transfusion or pregnancy are boosted with RhD-positive RBCs to maintain a high level of serum anti-D Ig. A significant proportion of primarily immunised individuals do not respond to RhD immunisation and are therefore unnecessarily exposed to the risks involved in RBC sensitisation. STUDY DESIGN AND METHODS: We genotyped 184 anti-D donors for ∼9000 immunological and inflammatory genetic polymorphisms on an Affymetrix GeneChip, and validated the results with a High-Resolution Melt analysis assay. We built and validated a predictive logistic regression model using High Responder and Non-Responder anti-D donors that incorporated highly-associated polymorphisms and gender. RESULTS: High Responder and Non-Responder profiles in anti-D donors were significantly associated with a shortlist of 13 genetic polymorphisms and sex of the donor. The derivation of a logistic regression model showed an accuracy rate of 92.6% that was subsequently validated as 60.0% with an independent set of donor samples. CONCLUSION: This study has developed a logistic regression model and a genotyping assay that can predict the responder profiles of anti-D donors and could potentially be applied to new donors and transfusion-dependent patients in a clinical setting. Additionally, target polymorphisms identified in immunological genes could help to elucidate the immunomodulatory pathways regulating the immune response to the RhD antigen, and to other RBC antigens.

Correlates of antiviral immune restoration in acute and chronic HIV type 1 infection: sustained viral suppression and normalization of T cell subsets.

Highly active antiretroviral therapy (HAART) has suppressed viral replication and facilitated normalization of T cell subsets, resulting in restoration of immunity against opportunistic pathogens. Induction of full immune restoration in chronically infected individuals, including HIV-specific helper T cell responses, is considered a priority, particularly if immunological control of HIV is to be achieved. Regimens containing dual protease inhibitors (PIs) have provided greater suppression of viremia than single-PI regimens. We therefore conducted a prospective analysis of factors associated with immune restoration after 3 years of therapy in two cohorts of acutely and chronically HIV-infected patients, comparing dual- versus single-PI regimens. Earlier and more durable returns of p24-specific proliferation were demonstrated in patients receiving dual-PI compared with single-PI regimens. Individuals with restored p24 responses had larger reductions in total HIV-specific cytotoxic T lymphocytes (CTLs) associated with stronger viral suppression, but Gag-specific CTLs remained higher, demonstrating that Gag-specific helper T cell responses were a critical component of functional immune restoration. On examination of clinical factors associated with immune restoration, we demonstrated that decreasing activation of CD8+ T cells (%CD8+ CD38+) and increasing proportions of CD4+ T cells were independently associated with restoration of p24 responses. Minimal immune activation, resulting from maximal suppression of viral replication, was required for long-term restoration and maintenance of Gag-specific T cell responses. This study uniquely demonstrates that dual-PI regimens are superior in achieving these levels of virological control and immune restoration in both chronic and acute infection, compared with single-PI or non-PI regimens.