Anaemia in acute HIV-1 subtype C infection

Evaluation of mean corpuscular volume among anemic people with HIV in North America following ART initiation

BACKGROUND

Anemia is common and associated with increased morbidity among people with HIV (PWH). Classification of anemia using the mean corpuscular volume (MCV) can help investigate the underlying causative factors of anemia. We characterize anemia using MCV among PWH receiving antiretroviral therapy (ART), and identify the risk factors for normocytic, macrocytic, and microcytic anemias.

METHODS

Including PWH with anemia (hemoglobin measure < 12.9 g/dL among men and < 11.9 g/dL among women) in the NA-ACCORD from 01/01/2007 to 12/31/2017, we estimated the annual distribution of normocytic (80-100 femtolitre (fL)), macrocytic (> 100 fL) or microcytic (< 80 fL) anemia based on the lowest hemoglobin within each year. Poisson regression models with robust variance and general estimating equations were used to estimate crude and adjusted prevalence ratios and 95% confidence intervals for risk factors for macrocytic (vs. normocytic) and microcytic (vs. normocytic) anemia stratified by sex.

RESULTS

Among 37,984 hemoglobin measurements that identified anemia in 14,590 PWH, 27,909 (74%) were normocytic, 4257 (11%) were microcytic, and 5818 (15%) were macrocytic. Of the anemic PWH included over the study period, 1910 (13%) experienced at least one measure of microcytic anemia and 3208 (22%) at least one measure of macrocytic anemia. Normocytic anemia was most common among both males and females, followed by microcytic among females and macrocytic among males. Over time, the proportion of anemic PWH who have macrocytosis decreased while microcytosis increased. Macrocytic (vs. normocytic) anemia is associated with increasing age and comorbidities. With increasing age, microcytic anemia decreased among females but not males. A greater proportion of PWH with normocytic anemia had CD4 counts ≤ 200 cells/mm3 and had recently initiated ART.

CONCLUSION

In anemic PWH, normocytic anemia was most common. Over time macrocytic anemia decreased, and microcytic anemia increased irrespective of sex. Normocytic anemia is often due to chronic disease and may explain the greater risk for normocytic anemia among those with lower CD4 counts or recent ART initiation. Identified risk factors for type-specific anemias including sex, age, comorbidities, and HIV factors, can help inform targeted investigation into the underlying causes.

TB epidemiology: where are the young women? Know your tuberculosis epidemic, know your response

Background

The global predominance of tuberculosis in men has received significant attention. However, epidemiological studies now demonstrate that there is an increased representation of young women with tuberculosis, especially in high HIV burden settings where young women bear a disproportionate burden of HIV. The role of the HIV epidemic, as well as changes in behavioural, biological, and structural risk factors are explored as potential explanations for the increasing burden of tuberculosis in young women.

Discussion

As young women are particularly vulnerable to HIV infection in sub-Saharan Africa, it is unsurprising that the TB epidemic in this setting has become increasingly feminised. This age-sex trend of TB in South Africa is similar to WHO estimates for other countries with a high HIV prevalence where there are more female than male cases notified up to the age of 25 years. The high prevalence of anaemia of chronic disease in young women with HIV is an additional potential reason for their increased TB risk. The widespread use of injectable medroxyprogesterone acetate contraception, which has been shown to possess selective glucocorticoid effect and oestrogen suppression, in young women may be an important emerging biological risk factor for tuberculosis in young women. Behavioural factors such as alcohol use and tobacco smoking patterns are further factors which may be responsible for the narrowing of the sex gap in TB epidemiology. In comparison to the significantly higher alcohol consumption rates in men globally, there is a narrowing gap in alcohol consumption between the sexes in South Africa with alarming rates of alcohol abuse in young women. There is a similar narrowing of the tobacco smoking gap between the sexes in South Africa, with increasing smoking prevalence in young women.

Conclusion

With nearly 70% of all TB patients being co-infected with HIV in our setting, it is not surprising that the age and sex distribution of TB is increasingly resembling the distribution of HIV in this region of dual hyperendemicity. New TB service design must begin to reflect the presence of young women as a significant group burdened by the disease.

Brief Report: Safety of Frequent Blood Sampling in Research Participants in an Acute HIV Infection Cohort in Thailand

Introduction:

Anemia is a potential adverse effect of phlebotomy during participation in research. Clinical studies of acute HIV infection (AHI) require frequent phlebotomy to maximize scientific yield, but this participant population may also be at increased risk for anemia and other adverse events.

Objective:

The objective of this study was to describe baseline and longitudinal hemoglobin changes among participants with AHI.

Methods:

Participants with AHI (n = 202) were enrolled in a prospective cohort study in Thailand. AHI was diagnosed using pooled nucleic acid testing and sequential HIV antibody immunoassays. Antiretroviral therapy was initiated on enrollment. During 48 weeks of study participation, a total of 629 mL of blood was drawn over 14 visits. Hemoglobin levels were measured serially, and abnormalities were graded using the Division of AIDS (National Institute of Allergy and Infectious Diseases) adverse event table.

Results:

AHI was diagnosed at a median of 18 days after infection. Mean hemoglobin at enrollment of male participants was 14.8 g/dL, and for females, it was 13.0 g/dL. Over 48 weeks, there was a mean increase of 0.2 g/dL among men (P = 0.01) and a decrease of 0.7 g/dL among women (P = 0.03). The overall prevalence of anemia was low, with 7 (3.5%) of 202 fulfilling grade 1 or 2 anemia criteria.

Conclusions:

Anemia was rare after frequent phlebotomy in research participants with AHI, before and after antiretroviral therapy. Given that the blood volume drawn from this study did not pose substantial clinical risk, increasing the volume of blood drawn for research purposes in acute HIV-infected research participants could be considered for future studies.

Hepcidin: Homeostasis and Diseases Related to Iron Metabolism

Iron is an essential metal for cell survival that is regulated by the peptide hormone hepcidin. However, its influence on certain diseases is directly related to iron metabolism or secondary to underlying diseases. Genetic alterations influence the serum hepcidin concentration, which can lead to an iron overload in tissues, as observed in haemochromatosis, in which serum hepcidin or defective hepcidin synthesis is observed. Another genetic imbalance of iron is iron-refractory anaemia, in which serum concentrations of hepcidin are increased, precluding the flow and efflux of extra- and intracellular iron. During the pathogenesis of certain diseases, the resulting oxidative stress, as well as the increase in inflammatory cytokines, influences the transcription of the HAMP gene to generate a secondary anaemia due to the increase in the serum concentration of hepcidin. To date, there is no available drug to inhibit or enhance hepcidin transcription, mostly due to the cytotoxicity described in the in vitro models. The proposed therapeutic targets are still in the early stages of clinical trials. Some candidates are promising, such as heparin derivatives and minihepcidins. This review describes the main pathways of systemic and genetic regulation of hepcidin, as well as its influence on the disorders related to iron metabolism.

Distinct patterns of hepcidin and iron regulation during HIV-1, HBV, and HCV infections

During HIV type-1 (HIV-1), hepatitis C virus (HCV), and hepatitis B virus (HBV) infections, altered iron balance correlates with morbidity. The liver-produced hormone hepcidin dictates systemic iron homeostasis. We measured hepcidin, iron parameters, cytokines, and inflammatory markers in three cohorts: plasma donors who developed acute HIV-1, HBV, or HCV viremia during the course of donations; HIV-1-positive individuals progressing from early to chronic infection; and chronically HIV-1-infected individuals (receiving antiretroviral therapy or untreated). Hepcidin increased and plasma iron decreased during acute HIV-1 infection, as viremia was initially detected. In patients transitioning from early to chronic HIV-1 infection, hepcidin in the first 60 d of infection positively correlated with the later plasma viral load set-point. Hepcidin remained elevated in individuals with untreated chronic HIV-1 infection and in subjects on ART. In contrast to HIV-1, there was no evidence of hepcidin up-regulation or hypoferremia during the primary viremic phases of HCV or HBV infection; serum iron marginally increased during acute HBV infection. In conclusion, hepcidin induction is part of the pathogenically important systemic inflammatory cascade triggered during HIV-1 infection and may contribute to the establishment and maintenance of viral set-point, which is a strong predictor of progression to AIDS and death. However, distinct patterns of hepcidin and iron regulation occur during different viral infections that have particular tissue tropisms and elicit different systemic inflammatory responses. The hypoferremia of acute infection is therefore a pathogen-specific, not universal, phenomenon.

Increased memory differentiation is associated with decreased polyfunctionality for HIV but not for cytomegalovirus-specific CD8+ T cells

The generation of polyfunctional CD8(+) T cells, in response to vaccination or natural infection, has been associated with improved protective immunity. However, it is unclear whether the maintenance of polyfunctionality is related to particular cellular phenotypic characteristics. To determine whether the cytokine expression profile is linked to the memory differentiation stage, we analyzed the degree of polyfunctionality of HIV-specific CD8(+) T cells within different memory subpopulations in 20 antiretroviral therapy-naive HIV-1-infected individuals at ∼34 wk postinfection. These profiles were compared with CMV-specific CD8(+) T cell responses in HIV-uninfected control subjects and in individuals chronically infected with HIV. Our results showed that the polyfunctional abilities of HIV-specific CD8(+) T cells differed according to their memory phenotype. Early-differentiated cells (CD45RO(+)CD27(+)) exhibited a higher proportion of cells positive for three or four functions (p < 0.001), and a lower proportion of monofunctional cells (p < 0.001) compared with terminally differentiated (TD; CD45RO(-)CD27(-)) HIV-specific CD8(+) T cells. The majority of TD HIV-specific CD8(+) T cells were monofunctional (median 69% [interquartile range: 57-83]), producing predominantly CD107a or MIP1β. Moreover, proportions of HIV-specific monofunctional CD8(+) T cells positively associated with proportions of TD HIV-specific CD8(+) T cells (p = 0.019, r = 0.54). In contrast, CMV-specific CD8(+) T cell polyfunctional capacities were similar across all memory subpopulations, with terminally and early-differentiated cells endowed with comparable polyfunctionality. Overall, these data show that the polyfunctional abilities of HIV-specific CD8(+) T cells are influenced by the stage of memory differentiation, which is not the case for CMV-specific responses.

Hematopoietic stem/precursor cells as HIV reservoirs

PURPOSE OF REVIEW

Although latent HIV-1 infection in CD4+ T cells contributes to HIV persistence, there is mounting evidence that other viral reservoirs exist. Here, we review recent data suggesting that the infection of hematopoietic progenitor cells creates additional reservoirs for HIV in vivo.

RECENT FINDINGS

New studies suggest that some types of hematopoietic progenitor cells have the potential to generate reservoirs for HIV. This review focuses on two types that can be infected by HIV in vitro and in vivo: multipotent hematopoietic progenitor cells in the bone marrow and circulating mast cell progenitors. Of these two types, only CD34+ bone marrow cells have been shown to harbor latent provirus in HIV-positive individuals with undetectable viral loads on highly active antiretroviral therapy (HAART). Latent infection of these long-lived cell types may create a significant barrier to HIV eradication; the infection of hematopoietic stem cells in particular could lead to an HIV reservoir that does not appreciably decay over the lifespan of the host.

SUMMARY

To eradicate HIV infection, it will be necessary to purge all viral reservoirs in the host. The findings highlighted here suggest that multipotent hematopoietic progenitor cells and possibly tissue mast cells may constitute significant reservoirs for HIV that must be addressed in order to eliminate HIV infection. Future studies are needed to determine which types of CD34+ cells are infected in vivo and whether infected CD34+ cells contribute to residual viremia in people with undetectable viral loads on HAART.

Antenatal HIV-1 RNA load and timing of mother to child transmission; a nested case-control study in a resource poor setting

Objective

To determine HIV-1 RNA load during the third trimester of pregnancy and evaluate its effect on in utero and intra-partum/postpartum transmissions in a breastfeeding population.

Design

A nested case-control study within a PMTCT cohort of antiretroviral therapy naive pregnant women and their infants.

Methods

A case was a mother who transmitted HIV-1 to her infant (transmitter) who was matched to one HIV-1 positive but non-transmitting mother (control).

Results

From a cohort of 691 pregnant women, 177 (25.6%) were HIV-1 positive at enrolment and from these 29 (23%) transmitted HIV-1 to their infants, 10 and 19 during in utero and intra-partum/postpartum respectively. Twenty-four mothers sero-converted after delivery and three transmitted HIV-1 to their infants. Each unit increase in log₁₀ viral load was associated with a 178 cells/mm³ and 0.2 g/dL decrease in TLC and hemoglobin levels, p = 0.048 and 0.021 respectively, and a 29% increase in the risk of transmission, p = 0.023. Intra-partum/postpartum transmitters had significantly higher mean viral load relative to their matched controls, p = 0.034.

Conclusion

Antenatal serum HIV-1 RNA load, TLC and hemoglobin levels were significantly associated with vertical transmission but this association was independent of transmission time. This finding supports the rationale for preventive strategies designed to reduce vertical transmission by lowering maternal viral load.

High prevalence of symptomatic acute HIV infection in an outpatient ward in southern Mozambique: identification and follow-up

OBJECTIVES

To determine the prevalence of acute HIV infection (AHI) within the HIV-seronegative adult population presenting with reported fever in a district hospital in southern Mozambique and evaluate clinical, immunological and virological parameters of AHI.

DESIGN

This is a prospective observational study.

METHODS

Three hundred and forty-six adults presenting with reported fever at an outpatient ward at the Manhiça District Hospital in Mozambique were screened for AHI by HIV rapid serology testing, followed by HIV-RNA testing in HIV-seronegative individuals. Plasma from HIV-seronegative patients was pooled in the ratio of 1: 5 for HIV-RNA testing. Whole blood was used for Plasmodium falciparum rapid test determination at screening visit. Follow-up visits at day 7, 4 and 10 months included clinical examination, HIV serotesting and assessment of HIV-RNA, CD4 cell counts and percentage of activated CD8 T cells.

RESULTS

HIV serotesting revealed that 37.8% (95% confidence interval 32.7-43.2) of the adults had previously undiagnosed established HIV infection. Among the HIV-seronegative patients, 3.3% (95% confidence interval 1.3-6.7) were found to have AHI as demonstrated by positive HIV-1 RNA testing. Median HIV-1 RNA levels at diagnosis of AHI were 6.21 log10 copies/ml (interquartile range 5.92-6.41) and significantly higher than median HIV-RNA load at 4 months. At day 7 after screening, patients showed a median CD4 cell count of 384 cells/microl (interquartile range 239-441) and a median percentage of activated CD8 T cells of 68.4% (interquartile range 59.6-87.8).

CONCLUSION

Of patients reporting with fever, 3.3% were shown to be potentially due to AHI. High prevalence of AHI in southern African populations may warrant investigation of tools and target populations for AHI screening as a novel way to address HIV prevention.

Association of HIV-specific and total CD8+ T memory phenotypes in subtype C HIV-1 infection with viral set point

Understanding early immunological events during HIV-1 infection that may set the course of disease progression is important for identifying correlates of viral control. This study explores the association of differentiation profiles of HIV-specific and total memory CD8(+) T cells with viral set point. A cohort of 47 HIV-1-infected individuals, with differing viral set points at 12 mo, were recruited during acute infection. We identified that the magnitude of IFN-gamma(+) T cell responses at 6 mo postinfection did not associate with viral set point at 12 mo. A subset of 16 individuals was further studied to characterize CD8(+) T cells for expression patterns of markers for memory differentiation, survival (CD127), senescence (CD57), and negative regulation (programmed death-1). We show that viral control and the predicted tempo of HIV disease progression in the first year of infection was associated with a synchronous differentiation of HIV-specific and total CD8(+) memory subpopulations. At 6-9 mo postinfection, those with low viral set points had a significantly higher proportion of early differentiated HIV-specific and total memory CD8(+) cells of a central memory (CD45RO(+)CD27(+)CCR7(+)) and intermediate memory (CD45RO(-)CD27(+)CCR7(-)) phenotype. Those with high viral set points possessed significantly larger frequencies of effector memory (CD45RO(+)CD27(-)CCR7(-)) cells. The proportions of memory subsets significantly correlated with CD38(+)CD8(+) T cells. Thus, it is likely that a high Ag burden resulting in generalized immune activation may drive differentiation of HIV-specific and total memory CD8(+) T cells.

Retrovirus-specificity of regulatory T cells is neither present nor required in preventing retrovirus-induced bone marrow immune pathology

Chronic viral infections of the hematopoietic system are associated with bone marrow dysfunction, to which both virus-mediated and immune-mediated effects may contribute. Using unresolving noncytopathic Friend virus (FV) infection in mice, we showed that unregulated CD4⁺ T cell response to FV caused IFN-γ-mediated bone marrow pathology and anemia. Importantly, bone marrow pathology was triggered by relative insufficiency in regulatory T (Treg) cells and was prevented by added Treg cells, which suppressed the local IFN-γ production by FV-specific CD4⁺ T cells. We further showed that the T cell receptor (TCR) repertoire of transgenic Treg cells expressing the β chain of an FV-specific TCR was virtually devoid of FV-specific clones. Moreover, anemia induction by virus-specific CD4⁺ T cells was efficiently suppressed by virus-nonspecific Treg cells. Thus, sufficient numbers of polyclonal Treg cells may provide substantial protection against bone marrow pathology in chronic viral infections.

Changes of colonic mucosal end-artery in human immunodeficiency virus-positive patients with chronic diarrhea due to nonspecific colitis

AIM: To observe the pathological changes of colonic mucosal end-artery in human immunodeficiency virus-positive [HIV(+)] patients with nonspecific colitis-caused chronic diarrhea.

METHODS: Colonoscopic pictures from 300 HIV-negative patients (3000 pictures in total) and 32 HIV(+) patients (600 pictures in total) with chronic diarrhea due to nonspecific colitis were comparatively analyzed. The pathological sections from the 32 HIV(+) patients were observed for analyses of capillary vessel distributions and mucosal bleedings in lamina propria.

RESULTS: The pictures from 9 HIV(+) patients with nonspecific colitis-caused chronic diarrhea showed ring-like changes of colonic mucosal end-artery with diameters of 1 to 2 mm, which became larger after bleeding. The same changes were not found in the 3000 pictures from the HIV-negative patients. In addition to chronic non-specific inflammation, mucosal bleeding and conglomeration of red blood cells in lamina propria were observed in the pathological sections of mucosal tissue from 13 HIV(+) patients, and mucosal vascular proliferation in lamina propria was found in 27 HIV(+) patients.

CONCLUSION: The ring-like change of colonic mucosal end-artery may be a special sign in HIV(+) patients with chronic diarrhea due to nonspecific colitis.

Establishing a cohort at high risk of HIV infection in South Africa: challenges and experiences of the CAPRISA 002 acute infection study

OBJECTIVES

To describe the baseline demographic data, clinical characteristics and HIV-incidence rates of a cohort at high risk for HIV infection in South Africa as well as the challenges experienced in establishing and maintaining the cohort.

METHODOLOGY/PRINCIPLE FINDINGS

Between August 2004 and May 2005 a cohort of HIV-uninfected women was established for the CAPRISA 002 Acute Infection Study, a natural history study of HIV-1 subtype C infection. Volunteers were identified through peer-outreach. The cohort was followed monthly to determine HIV infection rates and clinical presentation of early HIV infection. Risk reduction counselling and male and female condoms were provided. After screening 775 individuals, a cohort of 245 uninfected high-risk women was established. HIV-prevalence at screening was 59.6% (95% CI: 55.9% to 62.8%) posing a challenge in accruing HIV-uninfected women. The majority of women (78.8%) were self-identified as sex-workers with a median of 2 clients per day. Most women (95%) reported more than one casual sexual partner in the previous 3 months (excluding clients) and 58.8% reported condom use in their last sexual encounter. Based on laboratory testing, 62.0% had a sexually transmitted infection at baseline. During 390 person-years of follow-up, 28 infections occurred yielding seroincidence rate of 7.2 (95% CI: 4.5 to 9.8) per 100 person-years. Despite the high mobility of this sex worker cohort retention rate after 2 years was 86.1%. High co-morbidity created challenges for ancillary care provision, both in terms of human and financial resources.

CONCLUSIONS/SIGNIFICANCE

Challenges experienced were high baseline HIV-prevalence, lower than anticipated HIV-incidence and difficulties retaining participants. Despite challenges, we have successfully accrued this cohort of HIV-uninfected women with favourable retention, enabling us to study the natural history of HIV-1 during acute HIV-infection. Our experiences provide lessons for others establishing similar cohorts, which will be key for advancing the vaccine and prevention research agenda in resource-constrained settings.