Immunological and virological markers of HIV-disease progression

Cardiac MRI-Based Assessment of Myocardial Injury in Asymptomatic People Living With Human Immunodeficiency Virus: Correlation With nadir CD4 Count

BACKGROUND

There are known cardiac manifestations of HIV, but the findings in asymptomatic subjects are still not fully explored.

PURPOSE

To evaluate for the presence of subclinical myocardial injury in asymptomatic people living with human immunodeficiency virus (PLWH) by cardiac MRI and to explore the possible association between subclinical myocardial injury and HIV-related clinical characteristics.

STUDY TYPE

Cross-sectional.

POPULATION

A total of 80 asymptomatic PLWH (age: 53 years [47-56 years]; 90% male) and 50 age- and sex-matched healthy participants.

FIELD STRENGTH/SEQUENCE

A 3-T, cine sequence, T1, T2, and T2* mapping.

ASSESSMENT

Function analysis was derived from short axis, two-, three-, and four-chamber cine images by feature tracking. Regions of interest were manually selected in the midventricular septum T1, T2, and T2* mapping sequences. PLWH were evaluated for T1 increment (△T1 mapping = native T1 - cutoff values) and HIV-related clinical characteristics, particularly the nadir CD4 count. And PLWH were stratified into two groups according to the cutoff value of native T1: elevated native T1 and normal.

STATISTICAL TESTS

T test, Wilcoxon rank-sum test, Chi-square test, Spearman rank correlation, and logistic regression. P <0.05 indicated statistical significance.

RESULTS

Asymptomatic PLWH revealed significantly higher native myocardial T1 values (1241 ± 29 msec vs. 1189 ± 21 msec), T2 values (40.7 ± 1.5 msec vs. 37.9 ± 1.4 msec), and lower LVGRS (30.2% ± 6.2% vs. 35.8% ± 6.4%), LVGCS (-18.0% ± 2.5% vs. -19.5% ± 2.0%), and LVGLS (-16.0% ± 3.8% vs. -17.9% ± 2.6%) but showed no difference in T2* values (17.3 msec [16.3-19.1 msec] vs. 18.3 msec [16.5-19.3 msec], P = 0.201). A negative correlation between the native T1 increment in PLWH with subclinical myocardial injury and the nadir CD4 count (u = -0.316). Nadir CD4 count <500 cells/mm3 was associated with higher odds of elevated native T1 myocardial values (odds ratio, 6.12 [95% CI, 1.07-34.91]) in PLWH.

DATA CONCLUSION

Subclinical myocardial inflammation and dysfunction were present in asymptomatic PLWH, and a lower nadir CD4 count may be a risk factor for subclinical myocardial injury.

EVIDENCE LEVEL

1.

TECHNICAL EFFICACY

Stage 2.

Early estimation of the number of hidden HIV infected subjects: An extended Kalman filter approach

In the last decades several epidemic emergencies have been affecting the world, influencing the social relationships, the economics and the habits. In particular, starting in the early '80, the Acquired Immunodeficiency Syndrome, AIDS, is representing one of the most worrying sanitary emergency, that has caused up to now more than 25 million of dead patients. The infection is caused by the Human Immunodeficiency Virus, HIV, that may be transmitted by body fluids; therefore with wise behaviours the epidemic spread could rapidly be contained. This sanitary emergency is peculiar for the long incubation time: it can reach even 10 years, a long period in which the individual can unconsciously infect other subjects. The identification of the number of infected unaware people, mandatory to define suitable containment measures, is here obtained by using the extended Kalman filter applied to a noisy model in which, reasonably, only the number of infected diagnosed patients is available. Numerical simulations and real data analysis support the effectiveness of the approach.

Evaluation of the expression pattern of 4 microRNAs and their correlation with cellular/viral factors in PBMCs of Long Term non-progressors and HIV infected naïve Individuals

BACKGROUND

Long-term non-progressors (LTNPs) are small subsets of HIV-infected subjects that can control HIV-1 replication for several years without receiving ART. The exact mechanism of HIV-1 suppression has not yet been completely elucidated. Although the modulatory role of microRNAs (miRNAs) in HIV-1 replication has been reported, their importance in LTNPs is unclear.

OBJECTIVE

The aim of this cross-sectional study was to assess the expression pattern of miR-27b, -29, -150, and -221, as well as their relationship with CD4+ T-cell count, HIV-1 viral load, and nef gene expression in peripheral blood mononuclear cells (PBMCs) of untreated viremic patients and in LTNPs.

METHODS

MiRNAs expression levels were evaluated with real-time PCR assay using RNA isolated from PBMCs of LTNPs, HIV-1 infected naive patients, and healthy people. Moreover, CD4 T-cell count, HIV viral load, and nef gene expression were assessed.

RESULTS

The expression level of all miRNAs significantly decreased in the HIV-1 patient group compared to the control group, while the expression pattern of miRNAs in the LNTPs group was similar to that in the healthy subject group. In addition, there were significant correlations between some miRNA expression with viral load, CD4+ T-cell count, and nef gene expression.

CONCLUSION

The significant similarity and difference of the miRNA expression pattern between LNTPs and healthy individuals as well as between elite controllers and HIV-infected patients, respectively, showed that these miRNAs could be used as diagnostic biomarkers. Further, positive and negative correlations between miRNAs expression and viral/cellular factors could justify the role of these miRNAs in HIV-1 disease monitoring.

Naïve CD4+ cell counts significantly decay and high HIV RNA levels contribute to immunological progression in long-term non-progressors infected with HIV by blood products: a cohort study

BACKGROUND

Some long-term non-progressors (LTNPs) have decreasing CD4⁺ T cell counts and progress to AIDS. Exploring which subsets of CD4⁺ T cell decreasing and the determinants associated with the decay in these patients will improve disease progression surveillance and provide further understanding of HIV pathogenesis.

METHODS

Twenty-five LTNPs infected with HIV by blood products were classified as decreased (DG) if their CD4⁺ cell count dropped to < 400 cells/μL during follow-up or as non-decreased (non-DG) if their CD4⁺ cell count was ≥400 cells/μL. Laboratory and clinical assessments were conducted at 6 consecutive visits to identify DG characteristics.

RESULTS

The LTNPs were infected with HIV for 12 (IQR: 11.5-14) years, and 23 were classified as the B' subtype. Six individuals lost LTNP status 14.5 (IQR: 12.5-17.5) years after infection (DG), and the CD4⁺ T cell count decreased to 237 (IQR: 213-320) cells/μL at the latest visit. The naïve CD4⁺ T cell count decrease was greater than that of memory CD4⁺ T cells [- 128 (IQR: - 196, - 107) vs - 64 (IQR: - 182, - 25) cells/μL)]. Nineteen individuals retained LTNP status (non-DG). At enrolment, the viral load (VL) level (p = 0.03) and CD8⁺CD38⁺ percentage (p = 0.03) were higher in DG than non-DG individuals. During follow-up, viral load and CD8⁺CD38⁺ percentage were significantly increased and negatively associated with CD4⁺ cell count [(r = - 0.529, p = 0.008), (r = - 0.476, p = 0.019), respectively]. However, the CD8⁺CD28⁺ percentage and B cell count dropped in DG and were positively correlated with CD4⁺ T cell count [(r = 0.448, p = 0.028), (r = 0.785, p < 0.001)].

CONCLUSION

Immunological progression was mainly characterized by the decrease of naïve CD4⁺ T cell in LTNPs infected with HIV by blood products and it may be associated with high HIV RNA levels.

MicroRNAs and exosomes: key players in HIV pathogenesis

OBJECTIVES

HIV infection is well known to cause impairment of the human immune system, and until recently was a leading cause of death. It has been shown that T lymphocytes are the main targets of HIV. The virus inactivates T lymphocytes by interfering with a wide range of cellular and molecular targets, leading to suppression of the immune system. The objective of this review is to investigate to what extent microRNAs (miRNAs) are involved in HIV pathogenesis.

METHODS

The scientific literature (Pubmed and Google scholar) for the period 1988-2019 was searched.

RESULTS

Mounting evidence has revealed that miRNAs are involved in viral replication and immune response, whether by direct targeting of viral transcripts or through indirect modulation of virus-related host pathways. In addition, exosomes have been found to act as nanoscale carriers involved in HIV pathogenesis. These nanovehicles target their cargos (i.e. DNA, RNA, viral proteins and miRNAs) leading to alteration of the behaviour of recipient cells.

CONCLUSIONS

miRNAs and exosomes are important players in HIV pathogenesis. Additionally, there are potential diagnostic applications of miRNAs as biomarkers in HIV infection.

Low level expression of the Mitochondrial Antiviral Signaling protein (MAVS) associated with long-term nonprogression in SIV-infected rhesus macaques

BACKGROUND

Abnormally increased immune activation is one of the main pathological features of acquired immunodeficiency syndrome (AIDS). This study aimed to determine whether long-term nonprogression (LTNP) suppresses the upregulation of immune activation and to elucidate the mechanisms whereby the LTNP state is maintained.

METHODS

For this study we selected 4 rhesus macaques(RMs) infected with simian immunodeficiency virus (SIV) that were long-term nonprogressors (LTNP); for comparison we chose 4 healthy RMs that were seronegative for SIV (hereafter referred to as the Control group), and 4 progressing infection (Progressive group) SIV RMs. We observed these animals for 6 months without intervention and explored the immunological and pathological differences among the 3 groups. A series of immune activation and inflammation markers-such as C- C chemokine receptor type 5 (CCR5), beta 2- microglobulin (β2-MG), Human Leukocyte Antigen - antigen D Related (HLA-DR), CD38, the levels of microbial translocation (LPS -binding protein), and MAVS-and histological features were monitored during this period.

RESULTS

Both SIV RNA and SIV DNA in the plasma and lymph nodes (LNs) of the LTNP group were at significantly lower levels than those of the Progressive group (P < 0.05). The CD4/CD8 ratio and CD4 cell count and proportion in the LTNP group were between those of the Progressive and Control groups (P < 0.05): that is, they were higher than in the Progressive group and lower than in the Control group. The LTNP macaques manifested slow progression and decreased immune activation and inflammation; they also had lower levels of CCR5, LPS-binding protein, and β2-MG than the Progressive RMs (P < 0.05). Activation of LTNP in both CD4+ and CD8+ T cells was significantly lower than in the Progressive group and closer to that in the Control group. The histological features of the LTNP macaques were also closer to those of the Control group, even though they had been infected with SIV 4 years earlier. These data point to low viral replication in the LTNP macaques but it is not static. The expression of MAVS in peripheral blood and LNs was lower in the LTNP group than that in the Progressive group (P < 0.01), and MAVS was positively correlated with SIV DNA in LNs (P < 0.05). This may reflect the low activation of T lymphocytes. It was speculated that MAVS may be the link between innate and acquired antiviral immunity in SIV infection.

CONCLUSIONS

The LTNP RMs in our study were in a relatively stable state of low activation and inflammation, some biological progression with no disease events. This may have been associated with their low levels of the mitochondrial antiviral signaling protein (MAVS).

HIV Progression Depends on Codon and Amino Acid Usage Profile of Envelope Protein and Associated Host-Genetic Influence

Acquired immune deficiency syndrome (AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV). Two types of HIV have been characterized: HIV-1 and HIV-2. The present study investigated whether evolutionary selection pressure differs between rapid progressor (RP), slow progressor (SP), and long-term non-progressor (LTNP) of HIV-I infected individuals. An unexpected association between the evolutionary rate of substitution in envelope (env) gene and disease progression is observed. Our present study suggests that env genes of LTNP are subject to unusually strong functional constraint with respect to RP. We also observed that the three categories of env genes i.e., RP, SP, and LTNP, had their own characteristic pattern of amino acid usage and SP and LTNP sequences shared similar patterns of amino acid usage different from RP sequences and evolutionary rate significantly influenced the amino acid usage pattern of the three different types of env gene sequences. It was also noted that the evolutionary rate for the glycosylation sites of LTNP and SP sequences were even significantly less than the RP sequences. Comparative analysis on the influence of human host on the three categories of env genes are well correlated with the rates of disease progression suggesting the adaptive strategies of the viruses for successful residence and infection. Host associated selective constraints appeared most relaxed on the RP sequences and strongest in LTNP sequences. The present study clearly portrays how evolutionary selection pressure differs between three categories of env genes i.e., RP, SP, and LTNP. The env genes, coding for the env glycoproteins, experience severe selection constraints from the host due to their constant exposure to the host immune system. In this perspective it might be suggested that env gene evolution occurs mainly by negative selection with the occurrence of mutation that might not reach fixation in the viral population. This work also confers a deeper insight into the crucial effects of host factors that govern the overall progression of HIV infection.

MicroRNA Profile in CD8+ T-Lymphocytes from HIV-Infected Individuals: Relationship with Antiviral Immune Response and Disease Progression

Background

The relationship between host microRNAs (miRNA), viral control and immune response has not yet been elucidated in the field of HIV. The aim of this study was to assess the differential miRNA profile in CD8+ T-cells between HIV-infected individuals who differ in terms of viral replication control and immune response.

Methods

miRNA profile from resting and CD3/CD28-stimulated CD8+ T-cells from uninfected individuals (HIV-, n = 11), Elite Controllers (EC, n = 15), Viremic Controllers (VC, n = 15), Viremic Progressors (VP, n = 13) and HIV-infected patients on therapy (ART, n = 14) was assessed using Affymetrix miRNA 3.1 arrays. After background correction, quantile normalization and median polish summarization, normalized data were fit to a linear model. The analysis comprised: resting samples between groups; stimulated samples between groups; and stimulated versus resting samples within each group. Enrichment analyses of the putative target genes were perfomed using bioinformatic algorithms.

Results

A downregulated miRNA pattern was observed when resting samples from all infected groups were compared to HIV-. A miRNA downregulation was also observed when stimulated samples from EC, ART and HIV- groups were compared to VP, being hsa-miR-4492 the most downregulated. Although a preferential miRNA downregulation was observed when stimulated samples were compared to the respective resting samples, VP presented a differential miRNA expression pattern. In fact, hsa-miR-155 and hsa-miR-181a were downregulated in VP whereas in the other groups, either an upregulation or no differences were observed after stimulation, respectively. Overall, functional enrichment analysis revealed that the predicted target genes were involved in signal transduction pathways, metabolic regulation, apoptosis, and immune response.

Conclusions

Resting CD8+ T-cells do not exhibit a differential miRNA expression between HIV-infected individuals but they do differ from non-infected individuals. Moreover, a specific miRNA pattern is present in stimulated CD8+ T-cells from VP which could reflect a detrimental pattern in terms of CD8+ T-cell immune response.

Current status of medication adherence and infant follow up in the prevention of mother to child HIV transmission programme in Addis Ababa: a cohort study

Background

Prevention of mother to child HIV transmission (PMTCT) programmes have great potential to achieve virtual elimination of perinatal HIV transmission provided that PMTCT recommendations are properly followed. This study assessed mothers and infants adherence to medication regimen for PMTCT and the proportions of exposed infants who were followed up in the PMTCT programme.

Methods

A prospective cohort study was conducted among 282 HIV-positive mothers attending 15 health facilities in Addis Ababa, Ethiopia. Descriptive statistics, bivariate and mulitivariate logistic regression analyses were done.

Results

Of 282 mothers enrolled in the cohort, 232 (82%, 95% CI 77-86%) initiated medication during pregnancy, 154 (64%) initiated combined zidovudine (ZDV) prophylaxis regimen while 78 (33%) were initiated lifelong antiretroviral treatment (ART). In total, 171 (60%, 95% CI 55-66%) mothers ingested medication during labour. Of the 221 live born infants (including two sets of twins), 191 (87%, 95% CI 81-90%) ingested ZDV and single-dose nevirapine (sdNVP) at birth. Of the 219 live births (twin births were counted once), 148 (68%, 95% CI 61-73%) mother-infant pairs ingested their medication at birth. Medication ingested by mother-infant pairs at birth was significantly and independently associated with place of delivery. Mother-infant pairs attended in health facilities at birth were more likely (OR 6.7 95% CI 2.90-21.65) to ingest their medication than those who were attended at home. Overall, 189 (86%, 95% CI 80-90%) infants were brought for first pentavalent vaccine and 115 (52%, 95% CI 45-58%) for early infant diagnosis at six-weeks postpartum. Among the infants brought for early diagnosis, 71 (32%, 95% CI 26-39%) had documented HIV test results and six (8.4%) were HIV positive.

Conclusions

We found a progressive decline in medication adherence across the perinatal period. There is a big gap between mediation initiated during pregnancy and actually ingested by the mother-infant pairs at birth. Follow up for HIV-exposed infants seem not to be organized and is inconsistent. In order to maximize effectiveness of the PMTCT programme, the rate of institutional delivery should be increased, the quality of obstetric services should be improved and missed opportunities to exposed infant follow up should be minimized.

Variations in serum IL-7 and 90K/Mac-2 binding protein (Mac-2 BP) levels analysed in cohorts of HIV-1 patients and correlated with clinical changes following antiretroviral therapy

Serum levels of interleukin-7 (IL-7), a non-redundant cytokine that plays a crucial role in lymphopoiesis, are known to be elevated in HIV-1-infected subjects. To examine further the association between levels of IL-7, CD4+ cell counts and viraemia, we analysed these parameters in a large cohort of HIV-1 patients along with serum levels of 90K, a marker of disease severity but with no established involvement in lymphopoiesis. While IL-7 levels were only found to correlate with CD4+ cell counts, 90K levels presented strong correlations with both CD4+ cell numbers and with plasma viral loads (VLs). These correlations were maintained in patients naive to treatment with antiretrovirals (n = 38) but were abolished when the analysis was restricted to the group receiving highly active antiretroviral therapy (HAART, n = 82). Moreover, although 90K levels were significantly reduced in patients on HAART, IL-7 levels continued to be elevated despite successful treatment. The influence of HAART on the variations in these serum parameters was further assessed in a longitudinal study on 32 subjects. The HAART-induced decrease in VLs and increase in CD4+ counts were found to correlate with a reduced serum level of 90K and IL-7, respectively. Nevertheless, following a median period of 33 months of immunological and virological successful HAART, serum levels of IL-7 continued to be significantly elevated compared with those detected in healthy controls. These findings suggest that immunotherapy with IL-7, aimed to replenish T-cell stock in HAART-treated subjects, may have a limited impact on the process of immune reconstitution.

Atividade física e a infecção pelo HIV: uma análise crítica

A maioria dos estudos acerca dos efeitos da prática regular de exercícios físicos sobre o sistema imunológico de portadores do HIV envolve principal ou exclusivamente atividades aeróbias. Melhorias no condicionamento cardiorrespiratório e na saúde mental, com pouca ou nenhuma influência sobre variáveis relacionadas ao sistema imunológico (CD4, CD4/CD8, nº de cópias de RNA viral), têm sido reportadas. Comumente, tais estudos apresentam amostras reduzidas, com elevada evasão, nas quais indivíduos com distintos comprometimentos imunológicos (diferentes estágios da infecção) são submetidos ao mesmo programa de treinamento e seus resultados avaliados conjuntamente. O objetivo desta revisão foi identificar o nível de evidência científica e o grau de recomendação de exercícios aeróbios, de força e flexibilidade abordados nos principais estudos longitudinais investigando as influências físicas, psicológicas e/ou imunológicas da prática sistemática de atividades físicas em portadores do HIV. A partir disso, buscou-se também determinar linhas básicas para a prescrição de exercícios e para o desenvolvimento de estudos futuros. Verificou-se que nenhum estudo revisado apresentava nível I de evidência, o que significa haver um risco relevante de erro em relação às inferências estabelecidas. Freqüentemente, indivíduos em estágios mais avançados da infecção encontravam-se em menor número nas amostras, minimizando suas influências nos resultados. Em adendo, os estudos mais consistentes metodologicamente (nível II de evidência) compreendiam curta intervenção (6 a 12 semanas), o que inviabilizava a identificação de tendências negativas, principalmente em resposta aos exercícios mais intensos. Logo, uma prescrição segura de exercícios precisa levar em consideração: idade, sexo, história pregressa de atividade física, condicionamento físico, comprometimento orgânico e o objetivo do portador. As mesmas considerações cabem para o delineamento de estudos futuros, sendo de vital importância investigar os efeitos imunológicos de diferentes tipos de exercícios também em crianças e mulheres infectadas pelo HIV.

Revision of HIV center medical staging scale

HIV-related symptomatology represents both an indirect measure of immune functioning and a clinically significant indicator of disease progression. The most widely used classification system for HIV-related symptomatology is the Center for Disease Control (CDC) system. Although the CDC scale has widely recognized clinical utility, it provides only nominal-level measurement, which may be problematic for both clinicians and researchers. This article describes the revision and validation of the HIV Center Medical Staging Scale (rHCMSS), and ordinal-level physical illness scale that provides a means of independently measuring the progression of HIV-disease symptomatology and immunological decline. Concurrent use of the rHCMSS, the CDC classification system, and T-lymphocyte and viral load data will provide a more comprehensive indication of HIV-disease progression for clinical and research purposes.