Preservation of memory B cell homeostasis in an individual producing broadly neutralising antibodies against HIV-1.

Immunological determinants favouring emergence of broadly neutralising antibodies are crucial to the development of HIV-1 vaccination strategies. Here, we combined RNAseq and B cell cloning approaches to isolate a broadly neutralising antibody (bnAb) ELC07 from an individual living with untreated HIV-1. Using single particle cryogenic electron microscopy (cryo-EM), we show that the antibody recognises a conformational epitope at the gp120-gp41 interface. ELC07 binds the closed state of the viral glycoprotein causing considerable perturbations to the gp41 trimer core structure. Phenotypic analysis of memory B cell subsets from the ELC07 bnAb donor revealed a lack of expected HIV-1-associated dysfunction, specifically no increase in CD21-/CD27- cells was observed whilst the resting memory (CD21+/CD27+) population appeared preserved despite uncontrolled HIV-1 viraemia. Moreover, single cell transcriptomes of memory B cells from this bnAb donor showed a resting memory phenotype irrespective of the epitope they targeted or their ability to neutralise diverse strains of HIV-1. Strikingly, single memory B cells from the ELC07 bnAb donor were transcriptionally similar to memory B cells from HIV-negative individuals. Our results demonstrate that potent bnAbs can arise without the HIV-1-induced dysregulation of the memory B cell compartment and suggest that sufficient levels of antigenic stimulation with a strategically designed immunogen could be effective in HIV-negative vaccine recipients.

A national audit of the management of HIV-2 in adults in the UK.

BACKGROUND: HIV-2 is rare in the UK. Many UK centres therefore only treat small numbers of people and there are few clinical trials to guide treatment. The British HIV Association (BHIVA) 2010 guidelines for management of HIV-2 formed the basis for this national audit, which aims to describe current practice and adherence to guidelines. METHODS: All UK centres providing HIV care were contacted via the BHIVA "Members Matters" newsletter, and asked to submit anonymised, retrospective data for individuals living with HIV-2 accessing care at their service. RESULTS: Thirty-five sites responded and data were analysed for 167 individuals. Nearly half of individuals accessed care at one of four large London centres (77/167, 46%).Most people living with HIV-2 have taken antiretroviral therapy (ART) (132/167, 79%). The most common reasons for initiating treatment were clinical disease (34/89, 38%) and pregnancy (11/89, 12%). Most treatment-naïve individuals were initiated on a protease inhibitor based regimen (70/89, 79%). The use of integrase strand transfer inhibitor based regimens has increased over time.A significant minority of patients did not have baseline drug resistance testing performed, despite having a detectable viral load (15/52, 29%). Virological failure occurred in a minority of individuals (21/132, 16%); the most common drug regimen change in this context was the addition of an integrase strand transfer inhibitor (12/26 regimen changes, 46%). CONCLUSIONS: Most individuals living with HIV-2 were managed according to national guidance, with key areas for improvement including the choice of ART, drug resistance testing and the management of virological failure. It is hoped that this national audit, performed in conjunction with the updated 2021 BHIVA guidelines will improve the care of individuals living with HIV-2 in the UK.

Cotrimoxazole reduces systemic inflammation in HIV infection by altering the gut microbiome and immune activation.

Long-term cotrimoxazole prophylaxis reduces mortality and morbidity in HIV infection, but the mechanisms underlying these clinical benefits are unclear. Here, we investigate the impact of cotrimoxazole on systemic inflammation, an independent driver of HIV mortality. In HIV-positive Ugandan and Zimbabwean children receiving antiretroviral therapy, we show that plasma inflammatory markers were lower after randomization to continue (n = 144) versus stop (n = 149) cotrimoxazole. This was not explained by clinical illness, HIV progression, or nutritional status. Because subclinical enteropathogen carriage and enteropathy can drive systemic inflammation, we explored cotrimoxazole effects on the gut microbiome and intestinal inflammatory biomarkers. Although global microbiome composition was unchanged, viridans group Streptococci and streptococcal mevalonate pathway enzymes were lower among children continuing (n = 36) versus stopping (n = 36) cotrimoxazole. These changes were associated with lower fecal myeloperoxidase. To isolate direct effects of cotrimoxazole on immune activation from antibiotic effects, we established in vitro models of systemic and intestinal inflammation. In vitro cotrimoxazole had modest but consistent inhibitory effects on proinflammatory cytokine production by blood leukocytes from HIV-positive (n = 16) and HIV-negative (n = 8) UK adults and reduced IL-8 production by gut epithelial cell lines. Collectively we demonstrate that cotrimoxazole reduces systemic and intestinal inflammation both indirectly via antibiotic effects on the microbiome and directly by blunting immune and epithelial cell activation. Synergy between these pathways may explain the clinical benefits of cotrimoxazole despite high antimicrobial resistance, providing further rationale for extending coverage among people living with HIV in sub-Saharan Africa.

HIV-associated neurocognitive disease: case studies and suggestions for diagnosis and management in different patient subgroups.

The incidence of HIV-associated dementia has decreased significantly with the introduction of combination antiretroviral therapy; however, milder or more subtle forms of neurocognitive disorders associated with HIV appear to remain common. There is a lack of consensus on when to screen and on which methods are most appropriate for identifying patients at risk of neurocognitive impairment. Multiple factors (demographic, social, genetic, psychological and medical) can play a role in its aetiology and progression, including potential central nervous system toxicity of antiviral therapy. It is important to identify these factors in order to apply relevant management strategies. In this review, we discuss a series of case studies that address some of the challenges presented by the diagnosis and management of HIV-associated neurocognitive impairment in different patient types.

Disease Progression in HIV-1-Infected Viremic Controllers.

BACKGROUND: The mechanism of CD4 T-cell decline in HIV-1 infection is unclear, but the association with plasma viral RNA load suggests viral replication is involved. Indeed, viremic controller patients with low viral RNA loads typically maintain high CD4 T-cell counts. Within a local cohort of 86 viremic controllers, we identify a subgroup (18 "discord controllers") with low CD4 T-cell counts that present clinical uncertainty. The underlying mechanism accounting for CD4 T-cell decline in the face of low or undetectable plasma (RNA) viral load remains unresolved. The objective of this study was to investigate the viral and host immune system dynamics in discord controllers by measuring cellular HIV-1 DNA load, T-cell populations, and T-cell activation markers. METHODS: We compared discord controllers (viral RNA load <2000 copies/mL, <450 CD4 T-cells/mm) with typical controllers (viral RNA load <2000 copies/mL, >450 CD4 T-cells/mm) and progressors (viral RNA load >10,000 copies/mL, <450 CD4 T-cells/mm). We quantified CD4/CD8 naive/central memory/effector memory subsets (CD45RA/RO ± CD62L), activation levels (CD38HLA-DR), and HIV-1 DNA load. RESULTS: Discord controllers resembled progressors showing high viral DNA load, depletion of naive CD4 T-cells, and higher activation in all CD4 T-cell subsets, compared with typical controllers. They were similar to typical controllers with lower CD8 T-cell activation compared with progressors. CONCLUSIONS: Our data are consistent with a relationship between CD4 T-cell activation and disease progression. HIV-1 DNA load may be a better marker of viral replication and disease progression than viral RNA load. Lower level CD8 T-cell activation correlates with low viral RNA load but not with disease progression or viral DNA load.

The role of raltegravir in the treatment of HIV-2 infections: evidence from a case series.

We describe five patients with HIV-2 infection (four antiretroviral-experienced and one antiretroviral-naive) treated with a regimen containing raltegravir. All responded to treatment as demonstrated by viral load and CD4(+) T-cell count monitoring. Our series confirms the clinical effectiveness of raltegravir in HIV-2-infected patients when given with other antiretrovirals to which the virus is susceptible.

Importance of cytomegalovirus viraemia in risk of disease progression and death in HIV-infected patients receiving highly active antiretroviral therapy.

BACKGROUND: Before highly active antiretroviral therapy (HAART) became available, cytomegalovirus was a major cause of opportunistic infection in HIV-infected patients and was associated with accelerated progression to AIDS and death. We have investigated whether cytomegalovirus viraemia remains a significant risk factor for progression of HIV disease and death in the era of HAART. METHODS: 374 patients whose CD4-cell count had ever been below 100 per microL were enrolled in a prospective study. Serial blood samples were tested for cytomegalovirus by PCR. Rates of new cytomegalovirus disease, new AIDS-defining disorders, and death were calculated over a median follow-up of 37 months after stratification according to baseline and most recent cytomegalovirus PCR status at any point during follow-up. FINDINGS: Of 2969 PCR assays, 375 (12.6%) were positive for cytomegalovirus DNA. 259 (69.3%) patients were persistently negative for cytomegalovirus by PCR; 15 were persistently positive; and 100 were intermittently positive and negative. In multivariate models, cytomegalovirus PCR-positive status as a time-updated covariate was significantly associated with increased relative rates of progression to a new AIDS-defining disorder (2.22 [95% CI 1.27-3.88] p=0.005) and death (4.14 [1.97-8.70] p=0.0002). INTERPRETATION: Detection of cytomegalovirus in blood by PCR continues to identify patients with a poor prognosis, even in the era of HAART. Randomised controlled clinical trials of drugs active against cytomegalovirus are needed to investigate whether this virus is a marker or a determinant of HIV disease progression.

Rapid reconstitution of humoral immunity against cytomegalovirus but not HIV following highly active antiretroviral therapy.

OBJECTIVE: To determine the kinetics of reduction in human cytomegalovirus (HCMV) load and specific anti-glycoprotein B (gB) immune responses in patients with concurrent HCMV DNAaemia following the initiation of highly active antiretroviral therapy (HAART). DESIGN: Sequential analysis of eleven patients with HCMV DNAaemia who received HAART and eleven control patients with HCMV DNAaemia. METHODS: HCMV load was measured by quantitative competitive polymerase chain reaction and anti-gB, anti-HIV Env and Gag responses by an end-point dilution immunofluorescence assay using recombinant antigens expressed in insect cells. Estimates of the efficacy of the reconstituting immune system at controlling HCMV replication were based on previous dynamic models. RESULTS: In patients initiating HAART, HCMV DNA levels in blood declined rapidly, with a median half-life of 5.2 days, consistent with an efficacy of the reconstituting immune system at inhibiting HCMV replication of 52.8-85% (median, 61%). Commensurate with this decrease, a significant increase in anti-gB titres was observed in the post-HAART period (corresponding to an average fourfold increase in titre by 1 month rising to an eightfold increase at month 3; = 0.01). No changes in titre were observed in the control group or for anti-HIV Gag antibody levels, while anti-HIV Env antibody levels decreased after HAART. CONCLUSIONS: In patients with HCMV DNAaemia, reconstitution of humoral immunity to HCMV gB occurs rapidly following the initiation of HAART. These changes contrast with the patterns observed for anti-HIV humoral immune responses.

When can cytomegalovirus prophylaxis and maintenance therapy be stopped in HIV disease?

Highly active antiretroviral therapy (HAART) can restore immune responses to a variety of pathogens, including cytomegalovirus. Following successful HAART, prophylaxis and maintenance therapy for cytomegalovirus can safely be stopped in selected patients. However, the risk of cytomegalovirus disease progression recurs if HAART fails, and so these patients require careful monitoring.