Serum ferritin, desferrioxamine, and evolution of HIV-1 infection in thalassemic patients

Free Radical and Viral Infection: A Review from the Perspective of Ferroptosis

Free radicals, including reactive oxygen species (ROS) and reactive nitrogen species (RNS), play critical roles in various physiological activities such as cell differentiation, apoptosis, and vascular tension when existing in cells at low levels. However, excessive amounts of free radicals are harmful, causing DNA damage, lipid peroxidation, protein degeneration, and abnormal cell death. Certain viral infections induce cells to produce excessive free radicals, which in multiple ways help the virus to replicate, mature, and exit. Iron is a necessary element for many intracellular enzymes, involved in both cellular activities and viral replication. Ferroptosis, a programmed cell death mode distinct from apoptosis, necrosis, and pyroptosis, is characterized by lipid peroxide accumulation and damage to the antioxidant system, affecting many cellular processes. Viral infection commonly manifests as decreased glutathione (GSH) content and down-regulated glutathione peroxidase 4 (GPX4) activity, similar to ferroptosis. Recent studies have suggested a possible relationship among free radicals, viral infections and ferroptosis. This review aims to elucidate the molecular mechanism linking free radicals and ferroptosis during viral infections and provide a new theoretical basis for studying viral pathogenesis and control.

Iron intake is positively associated with viral load in antiretroviral naïve Brazilian men living with HIV

BACKGROUND

Iron homeostasis contribute for the human immunodeficiency virus (HIV) pathogenesis.

OBJECTIVES

We assessed the iron intake pattern in antiretroviral naïve Brazilian men living with HIV correlating with clinical and nutritional parameters.

METHODS

The iron consumption mean was estimated according to a food frequency questionnaire (FFQ), and a 3-day food record (3dFR) submitted to the patients. HIV viral load, CD4+ T cell counts, serum iron, haematological and anthropometrics parameters were recorded.

FINDINGS

Fifty-one HIV-infected adult men naïve for antiretroviral therapy (ART) were enrolled. The mean age of participants was 35 (SEM ± 1.28) years old, with mean time of HIV-1 infection of 1.78 (0-16.36, min-max) years. Majority (41.18%) had complete secondary, and 21.57% had tertiary educational level. The income was around 1x (54.90%) to 2x (41.18%) minimum wage. Fifty-four percent showed normal weight, while 40% were overweight. The patients showed normal mean values of haematological parameters, and mean serum iron was 14.40 µM (SEM ± 0.83). The FFQ showed moderate correlation with the 3dFR (ρ = 0.5436, p = 0.0009), and the mean values of iron intake were 10.55(± 0.92) mg/day, recorded by FFQ, and 15.75(± 1.51) mg/day, recorded by 3dFR. The iron intake, recorded by FFQ, negatively correlated with serum iron (ρ = -0.3448, p = 0.0132), and did not have influence in the CD4+ T cell counts [e.B 0.99 (0.97-1.01, 95% confidence interval (CI), p = 0.2]. However, the iron intake showed a positive effect in HIV viral load [e.B 1.12 (1.02-1.25, 95%CI), p < 0.01].

MAIN CONCLUSIONS

This study draws attention for the importance of iron intake nutritional counseling in people living with HIV. However, more studies are required to clarify the association between high iron intake and HIV infection and outcome.

Iron overload in myelodysplastic syndromes: Evidence based guidelines from the Canadian consortium on MDS

In 2008 the first evidence-based Canadian consensus guideline addressing the diagnosis, monitoring and management of transfusional iron overload in patients with myelodysplastic syndromes (MDS) was published. The Canadian Consortium on MDS, comprised of hematologists from across Canada with a clinical and academic interest in MDS, reconvened to update these guidelines. A literature search was updated in 2017; topics reviewed include mechanisms of iron overload induced cellular damage, evidence for clinical endpoints impacted by iron overload including organ dysfunction, infections, marrow failure, overall survival, acute myeloid leukemia progression, and endpoints around hematopoietic stem-cell transplant. Evidence for an impact of iron reduction on the same endpoints is discussed, guidelines are updated, and areas identified where evidence is suboptimal. The guidelines address common questions around the diagnosis, workup and management of iron overload in clinical practice, and take the approach of who, when, why and how to treat iron overload in MDS. Practical recommendations for treatment and monitoring are made. Evidence levels and grading of recommendations are provided for all clinical endpoints examined.

Iron overload in lower international prognostic scoring system risk patients with myelodysplastic syndrome receiving red blood cell transfusions: Relation to infections and possible benefit of iron chelation therapy

BACKGROUND

An increased incidence of infections and infectious mortality has been reported in myelodysplastic syndromes (MDS) patients receiving red blood cell (RBC) transfusions.

METHODS

We examined incidence of infections requiring antibiotics, antifungal or antiviral medications in transfused lower International Prognostic Scoring System (IPSS) risk MDS patients and whether this differed with iron chelation therapy (ICT).

RESULTS

138 transfused MDS patients were lower IPSS risk. 59 received ICT; median duration was 13 months. There was no significant difference between groups in neutrophil count at first RBC transfusion or first infection. Infections included: bacterial, n = 88; viral; fungal; and mycobacterial; n = 2 each. In ICT and non-ICT patients, respectively, infections were (number [%]): patients, 23 (40.0%) and 22 (27.8%); episodes (median [range]), 2 (1-6) and 2 (1-5); hospitalizations, 16 (27.1%) and 8 (10.1%); and deaths, 0 (0%) and 1 (1.3%), p = NS for all. Median overall survival (OS) from first RBC transfusion was superior in ICT patients, p = 0.01, and remained significant in a multivariate analysis (MVA), p = 0.003. Median time to first infection (TTI) was 27 and 7.8 months, respectively, p < 0.0001, and ICT remained significant for TTI in an MVA, p = 0.02, hazard ratio 0.3. For ICT patients with blast count <5%, TTI was significantly superior (p = 0.004).

CONCLUSIONS

In this retrospective analysis, for lower IPSS risk MDS patients receiving RBC transfusions, though number and type of infections were similar between groups and despite similar neutrophil counts, time to first infection was significantly longer in ICT patients (p < 0.0001). These results should be confirmed in larger, prospective analyses.

Drug-Based Lead Discovery: The Novel Ablative Antiretroviral Profile of Deferiprone in HIV-1-Infected Cells and in HIV-Infected Treatment-Naive Subjects of a Double-Blind, Placebo-Controlled, Randomized Exploratory Trial

Antiretrovirals suppress HIV-1 production yet spare the sites of HIV-1 production, the HIV-1 DNA-harboring cells that evade immune detection and enable viral resistance on-drug and viral rebound off-drug. Therapeutic ablation of pathogenic cells markedly improves the outcome of many diseases. We extend this strategy to HIV-1 infection. Using drug-based lead discovery, we report the concentration threshold-dependent antiretroviral action of the medicinal chelator deferiprone and validate preclinical findings by a proof-of-concept double-blind trial. In isolate-infected primary cultures, supra-threshold concentrations during deferiprone monotherapy caused decline of HIV-1 RNA and HIV-1 DNA; did not allow viral breakthrough for up to 35 days on-drug, indicating resiliency against viral resistance; and prevented, for at least 87 days off-drug, viral rebound. Displaying a steep dose-effect curve, deferiprone produced infection-independent deficiency of hydroxylated hypusyl-eIF5A. However, unhydroxylated deoxyhypusyl-eIF5A accumulated particularly in HIV-infected cells; they preferentially underwent apoptotic DNA fragmentation. Since the threshold, ascertained at about 150 μM, is achievable in deferiprone-treated patients, we proceeded from cell culture directly to an exploratory trial. HIV-1 RNA was measured after 7 days on-drug and after 28 and 56 days off-drug. Subjects who attained supra-threshold concentrations in serum and completed the protocol of 17 oral doses, experienced a zidovudine-like decline of HIV-1 RNA on-drug that was maintained off-drug without statistically significant rebound for 8 weeks, over 670 times the drug's half-life and thus clearance from circulation. The uniform deferiprone threshold is in agreement with mapping of, and crystallographic 3D-data on, the active site of deoxyhypusyl hydroxylase (DOHH), the eIF5A-hydroxylating enzyme. We propose that deficiency of hypusine-containing eIF5A impedes the translation of mRNAs encoding proline cluster ('polyproline')-containing proteins, exemplified by Gag/p24, and facilitated by the excess of deoxyhypusine-containing eIF5A, releases the innate apoptotic defense of HIV-infected cells from viral blockade, thus depleting the cellular reservoir of HIV-1 DNA that drives breakthrough and rebound.

TRIAL REGISTRATION

ClinicalTrial.gov NCT02191657.

Minimal impact of an iron-fortified lipid-based nutrient supplement on Hb and iron status: a randomised controlled trial in malnourished HIV-positive African adults starting antiretroviral therapy

Anaemia, redistribution of Fe, malnutrition and heightened systemic inflammation during HIV infection confer an increased risk of morbidity and mortality in HIV patients. We analysed information on Fe status and inflammation from a randomised, double blind, controlled phase-III clinical trial in Lusaka, Zambia and Mwanza, Tanzania. Malnourished patients (n 1815) were recruited at referral to antiretroviral therapy (ART) into a two-stage nutritional rehabilitation programme, randomised to receive a lipid-based nutrient supplement with or without added micronutrients. Fe was included in the intervention arm during the second stage, given from 2 to 6 weeks post-ART. Hb, serum C-reactive protein (CRP), serum ferritin and soluble transferrin receptor (sTfR) were measured at recruitment and 6 weeks post-ART. Multivariable linear regression models were used to assess the impact of the intervention, and the effect of reducing inflammation from recruitment to week 6 on Hb and Fe status. There was no effect of the intervention on Hb, serum ferritin, sTfR or serum CRP. A one-log decrease of serum CRP from recruitment to week 6 was associated with a 1.81 g/l increase in Hb (95% CI 0.85, 2.76; P< 0.001), and a 0.11 log decrease in serum ferritin (95% CI - 0.22, 0.03; P= 0.012) from recruitment to week 6. There was no association between the change in serum CRP and the change in sTfR over the same time period (P= 0.78). In malnourished, HIV-infected adults receiving dietary Fe, a reduction in inflammation in the early ART treatment period appears to be a precondition for recovery from anaemia.

Short communication: high cellular iron levels are associated with increased HIV infection and replication

HIV is a pandemic disease, and many cellular and systemic factors are known to alter its infectivity and replication. Earlier studies had suggested that anemia is common in HIV-infected patients; however, higher iron was also observed in AIDS patients prior to the introduction of antiretroviral therapy (ART). Therefore, the relationship between iron and viral infection is not well delineated. To address this issue, we altered the levels of cellular iron in primary CD4(+) T cells and showed that higher iron is associated with increased HIV infection and replication. In addition, HIV infection alone leads to increased cellular iron, and several ART drugs increase cellular iron independent of HIV infection. Finally, HIV infection is associated with increased serum iron in HIV-positive patients regardless of treatment with ART. These results establish a relationship between iron and HIV infection and suggest that iron homeostasis may be a viable therapeutic target for HIV.

The interaction between sickle cell disease and HIV infection: a systematic review

Human immunodeficiency virus (HIV) and sickle cell disease (SCD) are regarded as endemic in overlapping geographic areas; however, for most countries only scarce data on the interaction between HIV and SCD and disease burden exist. HIV prevalence in SCD patients varies between 0% and 11.5% in published studies. SCD has been suggested to reduce disease progression of HIV into AIDS. Various interactions of antiretroviral therapy with SCD exist. Both SCD and HIV act as common risk factors for stroke, avascular necrosis, severe splenic dysfunction, pulmonary arterial hypertension, and sepsis, which may result in synergistic increase in risk of developing these diseases. No treatment guidelines regarding SCD with HIV coinfection were identified. Available evidence is mainly based on small clinical studies, thus making strong recommendations difficult. An increased effort to elucidate the precise interactions is warranted to better understand both diseases and effect more adequate treatment approaches, especially in view of their geographical coprevalence.

Serum hepcidin levels in women infected with HIV-1 under antiviral therapy

Accumulating data suggest that iron may have a role in the regulation of HIV-infection. In the present study, we determined by radioimmunoassay the levels of hepcidin, a key regulator of iron homeostasis, in sera of 182 women infected with HIV-1 under highly active antiretroviral therapy (HAART). In the total cohort, hepcidin levels were lower in individuals infected with HIV than in controls (3.20 ± 3.06 vs. 5.68 ± 3.66 nmol/L, P = 0.009). Serum hepcidin concentrations were strongly correlated positively with iron, ferritin, urea, and uric acid. In the total cohort of patients with abnormal viral load and CD4 cell count <500 cells/mm(3) , a strong positive correlation was found between hepcidin and viral load. Hepcidin level was significantly higher in HIV-patients with high viremia than in patients with undetectable viral load. Iron level was significantly lower in HIV-patients with high viral load compared with patients with undetectable viral load. This study suggests that hepcidin controls serum iron, especially in response of iron utilization by HIV for viral replication. The possibility of using inhibitors of hepcidin expression as adjunct therapy for HIV-patients is discussed.

Lentiviral Nef suppresses iron uptake in a strain specific manner through inhibition of Transferrin endocytosis

BACKGROUND

Increased cellular iron levels are associated with high mortality in HIV-1 infection. Moreover iron is an important cofactor for viral replication, raising the question whether highly divergent lentiviruses actively modulate iron homeostasis. Here, we evaluated the effect on cellular iron uptake upon expression of the accessory protein Nef from different lentiviral strains.

RESULTS

Surface Transferrin receptor (TfR) levels are unaffected by Nef proteins of HIV-1 and its simian precursors but elevated in cells expressing Nefs from most other primate lentiviruses due to reduced TfR internalization. The SIV Nef-mediated reduction of TfR endocytosis is dependent on an N-terminal AP2 binding motif that is not required for downmodulation of CD4, CD28, CD3 or MHCI. Importantly, SIV Nef-induced inhibition of TfR endocytosis leads to the reduction of Transferrin uptake and intracellular iron concentration and is accompanied by attenuated lentiviral replication in macrophages.

CONCLUSION

Inhibition of Transferrin and thereby iron uptake by SIV Nef might limit viral replication in myeloid cells. Furthermore, this new SIV Nef function could represent a virus-host adaptation that evolved in natural SIV-infected monkeys.

Drug-induced reactivation of apoptosis abrogates HIV-1 infection

HIV-1 blocks apoptosis, programmed cell death, an innate defense of cells against viral invasion. However, apoptosis can be selectively reactivated in HIV-infected cells by chemical agents that interfere with HIV-1 gene expression. We studied two globally used medicines, the topical antifungal ciclopirox and the iron chelator deferiprone, for their effect on apoptosis in HIV-infected H9 cells and in peripheral blood mononuclear cells infected with clinical HIV-1 isolates. Both medicines activated apoptosis preferentially in HIV-infected cells, suggesting that the drugs mediate escape from the viral suppression of defensive apoptosis. In infected H9 cells, ciclopirox and deferiprone enhanced mitochondrial membrane depolarization, initiating the intrinsic pathway of apoptosis to execution, as evidenced by caspase-3 activation, poly(ADP-ribose) polymerase proteolysis, DNA degradation, and apoptotic cell morphology. In isolate-infected peripheral blood mononuclear cells, ciclopirox collapsed HIV-1 production to the limit of viral protein and RNA detection. Despite prolonged monotherapy, ciclopirox did not elicit breakthrough. No viral re-emergence was observed even 12 weeks after drug cessation, suggesting elimination of the proviral reservoir. Tests in mice predictive for cytotoxicity to human epithelia did not detect tissue damage or activation of apoptosis at a ciclopirox concentration that exceeded by orders of magnitude the concentration causing death of infected cells. We infer that ciclopirox and deferiprone act via therapeutic reclamation of apoptotic proficiency (TRAP) in HIV-infected cells and trigger their preferential elimination. Perturbations in viral protein expression suggest that the antiretroviral activity of both drugs stems from their ability to inhibit hydroxylation of cellular proteins essential for apoptosis and for viral infection, exemplified by eIF5A. Our findings identify ciclopirox and deferiprone as prototypes of selectively cytocidal antivirals that eliminate viral infection by destroying infected cells. A drug-based drug discovery program, based on these compounds, is warranted to determine the potential of such agents in clinical trials of HIV-infected patients.

Positive association between dietary iron intake and iron status in HIV-infected children in Johannesburg, South Africa

Anemia is a common complication of pediatric HIV infection and is associated with suboptimal cognitive performance and growth failure. Routine iron supplementation is not provided to South African HIV-infected children. We hypothesized that dietary iron intake without supplementation is sufficient to protect against iron deficiency (ID) in HIV-infected children receiving highly active antiretroviral therapy. In this prospective study, the difference between dietary intakes of iron-deficient children (soluble transferrin receptor >9.4 mg/L) and iron-sufficient children after 18 months on highly active antiretroviral therapy was examined. The association between iron intake and hemoglobin (Hb) concentration was also assessed. Longitudinal data collected for 18 months from 58 HIV-infected African children were assessed by generalized estimation equations, with adjustment for demographic information, dietary intakes, growth parameters, and CD4%. After adjustment for covariates, the longitudinal association between dietary iron intake and Hb concentration remained significant. This association shows that for every 1-mg increase in iron intake per day, Hb increases by 1.1 g/L (P < .001). Mean Hb increased significantly after 18 months of follow-up (106 ± 14 to 129 ± 14 g/L, P < .01), but soluble transferrin receptor also increased (7.7 ± 2.7 to 8.9 ± 3.0 mg/L, P < .01). The incidence of ID increased from 15.2% at baseline to 37.2% after 18 months. Children with animal protein intakes greater than >20 g/d had significantly lower odds for ID at 18 months than did children with lower intakes (odds ratio, 0.40; 95% confidence interval, 0.21-0.77). Dietary iron intake was insufficient to protect against ID, pointing to a need for low-dose iron supplementation for iron-deficient HIV-infected children and interventions to increase the consumption of animal protein.

Prevalence of anemia and underlying iron status in naive antiretroviral therapy HIV-infected children with moderate immune suppression

Anemia is common in HIV-infected children and iron deficiency is thought to be a common cause. This study investigates the prevalence of anemia, thalassemia, and underlying iron status in Thai and Cambodian children without advanced HIV disease to determine the necessity of routine iron supplementation. Antiretroviral (ARV)-naive HIV-infected Asian children aged 1-12 years, with CD4 15-24%, CDC A or B, and hemoglobin (Hb) ≥7.5 g/dl were eligible for the study. Iron studies, serum ferritin, Hb typing, and C-reactive protein were assessed. Anemia was defined as Hb <11.0 g/dl in children <5 years of age or <11.5 g/dl in children 5-12 years. We enrolled 299 children; 57.9% were female and the mean (SD) age was 6.3 (2.9) years. The mean (SD) CD4% and HIV-RNA were 20% (4.6) and 4.6 (0.6) log(10) copies/ml, respectively. The mean (SD) Hb and serum ferritin were 11.2 (1.1) g/dl and 78.3 (76.4) μg/liter, respectively. The overall iron deficiency anemia (IDA) prevalence was 2.7%. One hundred and forty-eight (50%) children had anemia, mostly of a mild degree. Of these, 69 (46.6%) had the thalassemia trait, 62 (41.8%) had anemia of chronic disease (ACD), 9 (6.1%) had thalassemia diseases, 3 (2.0%) had iron deficiency anemia, and 5 (3.4%) had IDA and the thalassemia trait. The thalassemia trait was not associated with increased serum ferritin levels. Mild anemia is common in ARV-naïve Thai and Cambodian children without advanced HIV. However, IDA prevalence is low; with the majority of cases caused by ACD. A routine prescription of iron supplement in anemic HIV-infected children without laboratory confirmation of IDA should be discouraged, especially in regions with a high prevalence of thalassemia and low prevalence of IDA.

Does venesection reduce HIV viral load in patients with hereditary haemochromatosis?

It is recognized that iron overload is associated with excess mortality in HIV/AIDS, and that this may be due to iron acting as an HIV-1 transcriptional activator. In vitro evidence using iron chelators suggests that therapeutic iron depletion may be beneficial in HIV-1 infection. We describe the clinical course of a Caucasian man with hereditary haemochromatosis and HIV infection where a significant drop in HIV viral load accompanied venesection over an 18-month period in the absence of HAART. We propose that further research should be undertaken to explore the relationship between HIV viral load and serum iron markers in hereditary haemochromatosis, with a view to evaluating the therapeutic benefit of venesection on HIV viral load in this setting.

The prevalence and etiology of anemia among HIV-infected children in India

In this report, the prevalence and multifactorial etiology of anemia among Indian human immunodeficiency virus (HIV)-infected children are described. HIV-infected children aged 2-12 years were prospectively enrolled in 2007-2008. Measured parameters included serum ferritin, vitamin B(12), red-cell folate, soluble transferrin receptor, and C-reactive protein. Children received antiretroviral therapy (ART), iron and, folate supplements as per standard of care. Among 80 enrolled HIV-infected children (mean age 6.8 years), the prevalence of anemia was 52.5%. Etiology of anemia was found to be iron deficiency alone in 38.1%, anemia of inflammation alone in 38.1%, combined iron deficiency and anemia of inflammation alone in 7.1%, vitamin B(12) deficiency in 7.1%, and others in 9.5%. Median iron intake was 5.7 mg/day (recommended dietary allowance 18-26 mg/day). Compared to nonanemic children, anemic children were more likely to be underweight (weight Z-score -2.5 vs. -1.9), stunted (height Z-score -2.6 vs. -1.9), with lower CD4 counts (18% vs. 24%, p < 0.01), and higher log viral load (11.1 vs. 7.1, p < 0.01). Hemoglobin (Hb) improved significantly among those who started ART (baseline Hb 11.6 g/dl, 6-month Hb 12.2 g/dl, p = 0.03). Children taking ART combined with iron supplements experienced a larger increase in Hb compared to those receiving neither ART nor iron supplements (mean Hb change 1.5 g/dl, p < 0.01).

CONCLUSION

Anemia, particularly iron deficiency anemia and anemia of inflammation, is highly prevalent among children with HIV infection. Micronutrient supplements combined with ART improved anemia in HIV-infected children.

Micronutrients, N-acetyl cysteine, probiotics and prebiotics, a review of effectiveness in reducing HIV progression

Low serum concentrations of micronutrients, intestinal abnormalities, and an inflammatory state have been associated with HIV progression. These may be ameliorated by micronutrients, N-acetyl cysteine, probiotics, and prebiotics. This review aims to integrate the evidence from clinical trials of these interventions on the progression of HIV. Vitamin B, C, E, and folic acid have been shown to delay the progression of HIV. Supplementation with selenium, N-acetyl cysteine, probiotics, and prebiotics has considerable potential, but the evidence needs to be further substantiated. Vitamin A, iron, and zinc have been associated with adverse effects and caution is warranted for their use.

Infections in thalassemia and hemoglobinopathies: focus on therapy-related complications

The clinical approach to thalassemia and hemoglobinopathies, specifically Sickle Cell Disease (SCD), based on transfusions, iron chelation and bone marrow transplantation has ameliorated their prognosis. Nevertheless, infections still may cause serious complications in these patients. The susceptibility to infections in thalassemia and SCD arises both from a large spectrum of immunological abnormalities and from exposure to specific infectious agents. Four fundamental issues will be focused upon as central causes of immune dysfunction: the diseases themselves; iron overload, transfusion therapy and the role of the spleen. Thalassemia and SCD differ in their pathogenesis and clinical course. It will be outlined how these differences affect immune dysfunction, the risk of infections and the types of most frequent infections in each disease. Moreover, since transfusions are a fundamental tool for treating these patients, their safety is paramount in reducing the risks of infections. In recent years, careful surveillance worldwide and improvements in laboratory tests reduced greatly transfusion transmitted infections, but the problem is not completely resolved. Finally, selected topics will be discussed regarding Parvovirus B19 and transfusion transmitted infections as well as the prevention of infectious risk postsplenectomy or in presence of functional asplenia.

Inhibition of HIV-1 gene expression by Ciclopirox and Deferiprone, drugs that prevent hypusination of eukaryotic initiation factor 5A

BACKGROUND

Eukaryotic translation initiation factor eIF5A has been implicated in HIV-1 replication. This protein contains the apparently unique amino acid hypusine that is formed by the post-translational modification of a lysine residue catalyzed by deoxyhypusine synthase and deoxyhypusine hydroxylase (DOHH). DOHH activity is inhibited by two clinically used drugs, the topical fungicide ciclopirox and the systemic medicinal iron chelator deferiprone. Deferiprone has been reported to inhibit HIV-1 replication in tissue culture.

RESULTS

Ciclopirox and deferiprone blocked HIV-1 replication in PBMCs. To examine the underlying mechanisms, we investigated the action of the drugs on eIF5A modification and HIV-1 gene expression in model systems. At early times after drug exposure, both drugs inhibited substrate binding to DOHH and prevented the formation of mature eIF5A. Viral gene expression from HIV-1 molecular clones was suppressed at the RNA level independently of all viral genes. The inhibition was specific for the viral promoter and occurred at the level of HIV-1 transcription initiation. Partial knockdown of eIF5A-1 by siRNA led to inhibition of HIV-1 gene expression that was non-additive with drug action. These data support the importance of eIF5A and hypusine formation in HIV-1 gene expression.

CONCLUSION

At clinically relevant concentrations, two widely used drugs blocked HIV-1 replication ex vivo. They specifically inhibited expression from the HIV-1 promoter at the level of transcription initiation. Both drugs interfered with the hydroxylation step in the hypusine modification of eIF5A. These results have profound implications for the potential therapeutic use of these drugs as antiretrovirals and for the development of optimized analogs.

Anemia and growth failure among HIV-infected children in India: a retrospective analysis

Background

Anemia and poor nutrition have been previously described as independent risk factors for death among HIV-infected children. We sought to describe nutritional status, anemia burden and HIV disease correlates among infected children in India.

Methods

We analyzed retrospective data from 248 HIV-infected children aged 1–12 years attending three outpatient clinics in South India (2004–2006). Standard WHO definitions were used for anemia, HIV staging and growth parameters. Statistical analysis included chi square, t tests, univariate and multivariate logistic regression analyses.

Results

The overall prevalence of anemia (defined as hemoglobin < 11 gm/dL) was 66%, and 8% had severe anemia (Hb < 7 gm/dL). The proportion of underweight and stunted children in the population was 55% and 46% respectively. Independent risk factors of anemia by multivariate analysis included the pre-school age group (age younger than 6 years) (OR: 2.87; 95% CI: 1.45, 5.70; p < 0.01), rural residence (OR: 12.04; 95% CI: 5.64, 26.00; p < 0.01), advanced HIV disease stage (OR: 6.95; 95% CI: 3.06, 15.79; p < 0.01) and presence of stunting (Height-for-age Z Score < -2) (OR: 3.24; 95% CI: 1.65, 6.35; p < 0.01). Use of iron/multivitamin supplementation was protective against risk of anemia (OR: 0.44; 95% CI: 0.22, 0.90; p = 0.03). Pulmonary tuberculosis was an independent risk factor in multivariate analysis (OR: 3.36; 95% CI: 1.43, 7.89; p < 0.01) when correlated variables such as HIV disease stage and severe immunodeficiency, and nutritional supplement use were not included. Use of antiretroviral therapy (ART) was associated with a reduced risk of anemia (OR: 0.29; 95% CI: 0.16, 0.53; p < 0.01). No significant association was found between anemia and gender, cotrimoxazole, or ART type (zidovudine versus stavudine).

Conclusion

The high prevalence and strong interrelationship of anemia and poor nutrition among HIV-infected children in India, particularly those living in rural areas underscores the need for incorporating targeted nutritional interventions during national scale up of care, support and treatment among HIV-infected children.

Iron supplementation for reducing morbidity and mortality in children with HIV

BACKGROUND

The most prevalent haematologic disturbance associated with HIV in children (apart from CD4 lymphocytopenia) is anaemia. Anaemia associated with HIV arises from multiple mechanisms, including the direct inhibitory effect of HIV on red cell precursors, other locally prevalent and/or opportunistic infections, micronutrient deficiency, anaemia of chronic disease, and as a consequence of medicines given for HIV and/or other concurrent illnesses. Iron deficiency is the most common cause of nutritional anaemia globally. There is significant geographical overlap of areas of the world where iron deficiency anaemia (IDA) and paediatric HIV are distributed. Given the high prevalence of IDA, it is likely that many HIV-infected children also are iron deficient. The contribution of iron deficiency to anaemia in HIV-infected children has been described but is incompletely understood. Currently, iron supplementation for anaemic infants and children is routinely practiced without any obvious effect in most developing countries, which bear most of the burden of global paediatric HIV infections.Because iron deficiency and IDA are common in HIV-infected children in high-prevalence areas and because there are concerns about possible deleterious effects of iron, this review aims to assess the evidence for iron supplementation for reducing morbidity and mortality in HIV-infected children.

OBJECTIVES

To determine whether iron supplementation improves clinical, immunologic, and virologic outcomes in children infected with HIV SEARCH STRATEGY: We used the comprehensive search strategy developed specifically by the Cochrane HIV/AIDS Review Group to identify HIV/AIDS randomised controlled trials, and searched the following electronic databases: MEDLINE (searched November 2007); Embase (searched December 2007); and CENTRAL (December 2007). This search was supplemented with a search of AIDSearch (searched December 2007) and NLM Gateway (searched December 2007) to identify relevant conference abstracts, as well as a search of the reference lists of all eligible articles. The search was not limited by language or publication status.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of iron supplementation in any form and dose in HIV-infected children aged 12 years and younger.

DATA COLLECTION AND ANALYSIS

We independently screened the results of the search to select potentially relevant studies and to retrieve the full articles. We independently applied the inclusion criteria to the potentially relevant studies. No studies were identified that fulfilled the selection criteria.

MAIN RESULTS

No RCTs of iron supplementation in HIV-infected children were found.

IMPLICATIONS FOR CLINICAL PRACTICE

The current clinical practice of iron supplementation in HIV-infected children is based on weak evidence comprising observational studies and expert opinions.

IMPLICATIONS FOR RESEARCH

High-quality RCTs of iron supplementation are urgently required, especially in areas with significant overlap of high prevalence of HIV, iron deficiency anaemia, and malaria. Policy makers should prioritise funding for these trials.

Elevated iron stores are associated with HIV disease severity and mortality among postpartum women in Zimbabwe

OBJECTIVES

The relationship between Fe status and HIV infection is complex and poorly understood. While anaemia is a major complication of HIV infection, higher Fe stores may be associated with disease progression. There is limited and conflicting data available from Africa.

DESIGN

Cross-sectional and prospective cohort study. SETTING, SUBJECTS AND METHODS: We examined the association between postpartum Fe status (Hb, serum ferritin (SF) and transferrin receptor (TfR)) and viral load (VL) and HIV-related mortality in 643 HIV-positive Zimbabwean women over a period of 12 months.

RESULTS

In non-anaemic women a log10 increase in SF was associated with a 2.3-fold increase in VL (P = 0.019); this association was absent in anaemic women. In prospective analyses, a log10 increase in SF was associated with a 4-fold increase in mortality by 12 months (P = 0.002). Hb was negatively associated with VL (P = 0.001) and mortality (P = 0.047). The adverse associations between SF and both VL and mortality were found at SF concentrations > 45 microg/l (P < 0.05). Controlling for alpha1 acid glycoprotein, a marker of inflammation, attenuated the association between both SF and VL and mortality, but these remained significant.

CONCLUSIONS

These results are consistent with the hypothesis that high Fe stores have adverse consequences in HIV infection. If adverse consequences are real, our data suggest that they occur at SF concentrations exceeding those consistent with adequate Fe nutriture.

Viral infection and iron metabolism

Fundamental cellular operations, including DNA synthesis and the generation of ATP, require iron. Viruses hijack cells in order to replicate, and efficient replication needs an iron-replete host. Some viruses selectively infect iron-acquiring cells by binding to transferrin receptor 1 during cell entry. Other viruses alter the expression of proteins involved in iron homeostasis, such as HFE and hepcidin. In HIV-1 and hepatitis C virus infections, iron overload is associated with poor prognosis and could be partly caused by the viruses themselves. Understanding how iron metabolism and viral infection interact might suggest new methods to control disease.

HIV-associated anemia in children: a systematic review from a global perspective

OBJECTIVES

To assess the importance of anemia in HIV-infected children in western and tropical settings.

DESIGN

A systematic review with a descriptive component.

METHODS

: Four databases were searched and reference lists of pertinent articles were checked. Studies that reported data on anemia or hemoglobin levels in HIV-infected children were selected and grouped according to the location and the definition of anemia.

RESULTS

Thirty-six studies met the inclusion criteria. Mild (hemoglobin <11 g/dl) and moderate (hemoglobin <9 g/dl) anemia were more prevalent with HIV infection (odds ratio 4.5; 95% confidence interval 2.5-8.3 and odds ratio 4.5; 95% confidence interval 2.0-10.3, respectively). Mean hemoglobin levels were lower (standardized mean difference; 0.79; 95% confidence interval 0.47-1.10). These differences were observed in both western and tropical settings. Anemia incidence ranged from 0.41 to 0.44 per person-year. There was limited data on more severe anemia (hemoglobin <7 or <5 g/dl). As anemia was frequently identified as an independent risk factor for disease progression and death, we next reviewed the limited data to formulate better strategies. Failure of erythropoiesis was the most important mechanism for anemia in HIV-infected children. Therapeutic options include highly active antiretroviral therapy and prevention or treatment of secondary infections. Erythropoietin can improve anemia in children, but it has not been evaluated in developing countries. Micronutrient supplementation may be helpful in individual children. The potential benefits or risks of iron supplementation in HIV-infected children require evaluation.

CONCLUSION

Anemia is a very common complication of pediatric HIV infection, associated with a poor prognosis. With the increasing global availability of highly active antiretroviral therapy, more data on the safety and efficacy of possible interventions in children are urgently needed.

Elevated iron status strongly predicts mortality in West African adults with HIV infection

OBJECTIVE

To comprehensively assess iron status and determine whether elevated iron status, like anemia, predicts mortality.

METHODS

We followed 1362 Gambian adults (53% female) in an HIV-seroprevalent clinic-based cohort over 11.5 years to ascertain all-cause mortality. Baseline iron status (iron, soluble transferrin receptor [sTfR], transferrin, ferritin, transferrin saturation, log [transferrin receptor: ferritin]), age, gender, ethnicity, hemoglobin, body mass index, HIV type, absolute CD4 count, malaria status, and [alpha]-(1)-antichymotrypsin were measured.

RESULTS

The mortality rate was 25.9/100 person-years. Elevated iron universally predicted greater mortality compared to normal iron status for all iron status indices, with the exception of sTfR in unadjusted models. In fully adjusted models, transferrin (elevated vs. normal, hazard ratio [HR]: 1.77; 95% confidence interval [CI]: 1.30 to 2.42; P < 0.001), ferritin (elevated vs. normal, HR: 1.40; 95% CI: 1.07 to 1.83; P = 0.014), and the combined iron status index (highly elevated vs. normal, HR: 2.20; 95% CI: 1.16 to 4.18; P = 0.016) remained significant predictors. As expected, hemoglobin (Hb) concentration and absolute CD4 counts were each inversely associated with mortality.

CONCLUSIONS

Elevated iron status predicts mortality in HIV infection, even after adjustment for immunosuppression and other confounders. This finding has implications in the clinical monitoring of disease progression and for iron-supplementation practices in areas of high HIV prevalence.

Iron status is an important cause of anemia in HIV-infected Tanzanian women but is not related to accelerated HIV disease progression

In HIV-infected populations from developing countries, it is unclear what proportion of anemia is attributable to iron deficiency (ID) and whether high body iron stores worsen HIV disease progression. We therefore evaluated these research questions in 584 HIV-infected Tanzanian women. Hemoglobin (Hb), serum ferritin (SF), serum transferrin receptor (sTfR), and C-reactive protein (CRP) concentrations were evaluated between 13 and 43 wk after women gave birth. ID was defined as SF or sTfR outside normal ranges, and ID anemia (IDA) as ID plus low Hb. In multivariate Cox regression models, the association between SF and HIV disease progression was assessed. Participants received iron + folate supplements during pregnancy. Hb (r = -0.159; P = 0.0001), SF (r = 0.355; P < 0.0001), and sTfR/log SF index (r = -0.119; P = 0.004) were related to CRP, whereas sTfR (r = 0.029; P = 0.48) was not. Prevalence estimates were 39.7% for ID and 23.6% for IDA. ID was associated with 48.9% of anemia cases. Categories of SF were not significantly associated with HIV-related mortality or progression to stage 4. Nevertheless, SF > 150.0 microg/L was related to a nonsignificantly elevated risk of progression to stage 4 (rate ratio = 1.78; 95% CI = 0.68-4.64; P = 0.24) compared with SF < 12.0 microg/L. In HIV-infected, parous women from sub-Saharan Africa, ID is of moderately high prevalence and is an important underlying cause of anemia. High storage iron does not appear to be related to HIV disease progression in this population, but more research on the role of iron during HIV disease is needed.

Effect of micronutrients and iron supplementation on hemoglobin, iron status, and plasma hepatitis C and HIV RNA levels in female injection drug users: a controlled clinical trial

BACKGROUND

Iron deficiency is common among female injection drug users, but it is unclear whether iron supplementation can reduce anemia and improve iron status without increasing plasma hepatitis C virus (HCV) or HIV RNA levels.

METHODS

We conducted a phase 3, double-blind, randomized, controlled clinical trial of daily micronutrients with 18 mg of iron (iron group) versus micronutrients without iron (control group) for 12 months among hepatitis C-positive female injection drug users in Baltimore, Maryland. The main outcome measures were hemoglobin, markers of iron status, plasma HCV RNA, plasma HIV RNA, and liver enzymes at 6 and 12 months of follow-up.

RESULTS

Four hundred fifty-eight women (320 HIV-negative and 138 HIV-positive) enrolled in the trial. There were no significant differences in the proportion of women with anemia, ferritin<30 ng/mL, log10 plasma HCV RNA, or log10 plasma HIV RNA between treatment groups at enrollment. The proportion with anemia in the iron and control groups, respectively, was 20.7% versus 31.3% (P=0.026) at 6 months and 26.2% versus 30.4% (P=0.5) at 12 months; with ferritin<30 ng/mL, the proportion was 29.2% versus 55.5% (P<0.0001) at 6 months and 26.2% versus 46.9% (P=0.0018) at 12 months. In the iron and control groups, respectively, mean log10 plasma HCV RNA (IU/mL) was 5.2 versus 5.2 (P=0.86) at 6 months and 5.4 versus 5.3 (P=0.6) at 12 months. Among HIV-positive subjects, mean log10 plasma RNA (copies/mL) in the iron and placebo groups, respectively, was 3.8 versus 3.7 (P=0.75) at 6 months and 3.7 versus 4.1 (P=0.19) at 12 months. There were no significant differences in liver enzyme levels between the treatment groups at enrollment, 6 months, and 12 months.

CONCLUSIONS

A daily micronutrient supplement with iron can reduce anemia and improve iron status in female injection drug users without increasing plasma HCV or HIV RNA levels or altering liver enzymes.

Iron and infection: effects of host iron status and the iron-regulatory genes haptoglobin and NRAMP1 (SLC11A1) on host-pathogen interactions in tuberculosis and HIV

There are many lines of evidence illustrating that iron plays a pivotal role in modulating the battle for survival between mammalian hosts and their pathogens. Each displays considerable genetic investment in a wide range of mechanisms for acquiring and maintaining iron. These competitive mechanisms are highly complex, existing within an interacting matrix of absorption, transport, storage and detoxification systems, each of which are iron-responsive and thus able to adapt to the different phases of infection. Considerable genetic polymorphism in some of these systems, with signals of geographic selection in the hosts, and niche selection in the pathogens, indicates that they are critical for species survival. In this review we briefly summarize the role of iron in host immune function before reviewing the available evidence that iron modulates susceptibility and disease outcomes in HIV and TB (tuberculosis). We then examine the putative role of iron-related host genes by focussing on two candidate genes, haptoglobin and NRAMP1, for which there are common polymorphic variants in humans with strong evidence of functionally distinct biochemical phenotypes that would be predicted to influence the course of HIV and TB infections. Finally, we examine the limited evidence so far available that nutrient-gene interactions are likely to influence the way in which gene variants can protect against infection. We conclude that there is a wealth of evidence associating alterations in iron balance and in iron-regulatory systems with disease progression, but that many issues related to the direction of causality, mechanisms of action and sensitivity to pharmacological intervention remain to be elucidated. Since iron is probably the most widely prescribed compound throughout the world, used in both preventative and treatment regimens, a deeper understanding of the host-pathogen interactions relating to iron constitutes an important area for both basic and clinical research.

Low-dose iron supplementation does not increase HIV-1 load

Observational data suggest that iron may increase HIV replication and the rate of progression of HIV infection. This is worrying, and may impede the international commitment to combat iron deficiency. However, it is crucial to clarify the role of iron in HIV infections, since iron is universally administered to anaemic patients and pregnant women, even in areas with high HIV prevalence. Based on a historical iron trial, we assessed the effect of 60 mg of elemental iron given twice weekly over four month on HIV-1 viral load. There was no effect on viral load, but effects of higher doses of iron cannot be excluded.

Potential risk for infection and atherosclerosis due to iron therapy

Iron is an essential nutrient, but carries potential risks. Iron therapy not only affects the functions of leukocytes, endothelial cells, and cytokine production, but also causes oxidative stress and can support bacterial growth. Intravenous iron therapy may result in nontransferrin-bound iron. This may act as a catalytic agent in the formation of hydroxyl radicals, and thus potentially contribute to cell damage and atherosclerosis. Potential long-term complications of intravenous iron therapy in end-stage renal disease patients include atherosclerosis and infection, particularly in patients with iron overload.

Iron, haptoglobin phenotype, and HIV-1 viral load: a cross-sectional study among pregnant Zimbabwean women

BACKGROUND

Viral load is a determinant of HIV-1 progression and transmission. Iron status and the phenotype of haptoglobin, a heme-binding acute phase reactant, may be determinants of viral load. We aimed to describe the effect of iron status, haptoglobin phenotype (Hp), and other predictors on HIV-1 viral load.

METHODS

Based on a cross-sectional study among 1669 antenatal care attenders (22-35 weeks) in Zimbabwe, 526 (31.5%) were found to be HIV infected. The role of season, age, gravidity, gestational age, malaria parasitemia, Hp, and elevated serum alpha(1)-antichymotrypsin (ACT) as well as serum ferritin, folate, retinol, and beta-carotene on HIV viral load among the 526 HIV-infected women was assessed using multiple linear regression analysis.

RESULTS

The distribution of Hp 1-1 (32%), Hp 2-1 (48%), and Hp 2-2 (20%) was not different from that of 53 uninfected women. Mean viral load was 3.85 log(10) (95% CI: 3.77-3.93) genome equivalents (geq)/mL, ranging from 3.77 (95% CI: 3.64-3.90) geq/mL in women with Hp 1-1 to 4.05 (95% CI: 3.81-4.21) geq/mL in women with Hp 2-2. With elevated serum ACT controlled for, women with Hp 2-2 had viral loads twice (95% CI: 1.4-4.0, p =.002) that of women with Hp 1-1, whereas those with serum ferritin <6 micro g/L had viral loads less than one third (95% CI: 0.13-0.53, p =.013) that of women with serum ferritin >24 micro g/L. Viral loads were also higher in women enrolled in the early rainy season compared with the dry season, in gravidae 4+ compared with gravidae 1 through 3, and in those with moderately elevated compared with low serum alpha(1)-antichymotrypsin, but neither age, gestational age, serum folate, serum retinol, nor serum beta-carotene were predictors.

CONCLUSION

Storage iron, Hp 2-2, and elevated ACT are independent positive predictors of HIV-1 viral load. The positive relationship between serum ferritin and viral load was not the result of an acute phase response or iron accumulation with advanced HIV infection. A possible detrimental role of iron in HIV infection would have serious public health implications.

Iron supplementation during human immunodeficiency virus infection: a double-edged sword?

Although iron supplementation is considered beneficial for groups at risk for anemia, concern has been raised that it could be harmful during human immunodeficiency virus (HIV) infection. Studies suggest: (1) faster HIV disease progression in thalassemia major patients receiving inadequate doses of iron-chelating drug; (2) higher mortality among patients receiving iron supplementation with dapsone compared with aerosolized pentamidine for prophylaxis against Pneumocytis carinii pneumonia; (3) higher iron stores and mortality among patients with haptoglobin Hp 2-2 phenotype; and (4) shorter survival among patients with high bone marrow iron deposition. These studies largely involved men in developed countries. Among HIV-infected pregnant women in Africa with a high prevalence of iron deficiency, no relationship was found between indicators of iron status and HIV disease severity. The available data do not contraindicate the current practice of iron supplementation in developing countries where there is a high prevalence of both HIV infection and iron deficiency.

Iron metabolism, free radicals, and oxidative injury

Iron has the capacity to accept and donate electrons readily. This capability makes it physiologically essential, as a useful component of cytochromes and oxygen-binding molecules. However, iron is also biochemically dangerous; it can damage tissues by catalyzing the conversion of hydrogen peroxide to free-radical ions that attack cellular membranes, protein and DNA. This threat is reduced in the healthy state where, because of the fine iron metabolism regulation, there is never appreciable concentration of 'free iron'. Under pathological conditions, iron metabolism and superoxide metabolism are clearly interactive. Each can exacerbate the toxicity of the other. Iron overload may amplify the damaging effects of superoxide overproduction in a very broad spectrum of inflammatory, both acute and chronic, conditions. Furthermore, chronic oxidative stress may modulate iron uptake and storage, leading to a self-sustained and ever-increasing spiral of cytotoxic and mutagenic events. The iron chelator deferroxamine is able to chelate 'free iron' even inside the cell. Its regular clinical use is to promote the excretion of an iron overload, when phlebotomy is harmful, and the dosage varies between 2-10 g/d. In conditions where deferroxamine is used to prevent the iron-driven oxygen toxicity, i.e., acute or chronic inflammatory diseases with oxidative stress, the dosage can be extremely reduced and the addition of antioxidants could be useful.

HIV and other predictors of serum folate, serum ferritin, and hemoglobin in pregnancy: a cross-sectional study in Zimbabwe

BACKGROUND

Folate and iron status and hemoglobin concentrations are important to maternal and infant health.

OBJECTIVE

Our goal was to identify predictors of serum folate, serum ferritin, and hemoglobin.

DESIGN

This was a cross-sectional study of 1669 pregnant women (22-35 wk of gestation) in Harare, Zimbabwe, who were receiving prenatal care. The statistical effects of age, season, gestational age, gravidity, HIV-1 infection, malaria parasitemia, and serum alpha1-antichymotrypsin (ACT) on serum folate, serum ferritin (log10 transformed), and hemoglobin were estimated by using multiple linear regression analyses.

RESULTS

Serum folate (x: 11.4 micromol/L) was 0.52-nmol/L (95% CI: 0.04, 1.0) lower in HIV-infected women than in uninfected women and 0.65-nmol/L (0.014, 1.28) lower in weeks 25-35 than in weeks 22-25. Serum ferritin (geometric x: 11.6 microg/L) was 0.93 times (0.86, 0.99) lower in HIV-infected women and 2.25 times (1.41, 3.61) higher in women with malaria parasitemia than in uninfected women. Similarly, serum ferritin was 0.71 times (0.63, 0.79) higher in weeks 32-35 than in weeks 22-25 and 1.21 times (1.12, 1.29) higher in gravida > or =3 than in gravida 1. Elevated serum ACT was a strong predictor of serum folate, serum ferritin, and hemoglobin. HIV infection was associated with a 12.9-g/L (8.9, 16.8) lower hemoglobin concentration in women with nondepleted iron stores but low serum retinol and a 7-8-g/L lower hemoglobin concentration in women with other combinations of serum ferritin and retinol (P for interaction = 0.038). Season, age, gestational age, and gravidity were not significant predictors of hemoglobin. Low serum folate, ferritin, and retinol were associated with low hemoglobin.

CONCLUSIONS

HIV was associated with lower serum folate, serum ferritin, and hemoglobin. HIV infection was also associated with lower hemoglobin, particularly in women with stored iron and low serum retinol. Low serum folate, ferritin, and retinol were associated with low hemoglobin.

Iron status and indicators of human immunodeficiency virus disease severity among pregnant women in Malawi

The relationships among hemoglobin, ferritin, and transferrin receptor levels and 2 markers of human immunodeficiency virus (HIV) disease severity--HIV load and CD4(+) lymphocyte count--were characterized among 483 pregnant women in Malawi, Africa. The only significant correlation was an inverse correlation between hemoglobin level and plasma HIV load (r=-.104; P<.03). The prevalence of iron deficiency anemia was not significantly different across quartiles of HIV load or CD4(+) lymphocyte count. In contrast to previous studies, these data suggest that iron status is not related to markers of HIV disease severity in pregnant women in Africa.

Iron status and the outcome of HIV infection: an overview

BACKGROUND

Theoretical considerations and experiments in the laboratory suggest that excessive iron stores may have an adverse effect on immunity. If so, high iron stores might be especially a problem in patients with human immunodeficiency virus (HIV) infection.

OBJECTIVE AND STUDY DESIGN

Review published clinical studies that provide information regarding the effect of iron status on the outcome of HIV infection.

RESULTS

Four clinical observations have provided some perspective on the effect of iron status on the outcome of HIV-1 infection. First, in a retrospective study of HIV-positive thalassemia major patients, the rate of progression of HIV disease was significantly faster in patients with lower doses of desferrioxamine and higher serum ferritin concentrations. Second, the inadvertent simultaneous administration of low doses of oral iron with dapsone for the prophylaxis of Pneumocystis carinii pneumonia in HIV-positive patients may have been associated with excess mortality. Third, a study of haptoglobin polymorphisms in HIV-positive subjects indicated that the haptoglobin 2-2 polymorphism is associated with higher iron stores and shortened survival as compared with the haptoglobin 1-1 or 2-1 phenotypes. Fourth, a retrospective study of bone marrow macrophage iron in HIV-positive patients suggested that survival is shorter with high iron stores.

CONCLUSION

These four observations raise the possibility that high iron status may adversely influence the outcome of HIV-1 infection.

Effect of transfusional iron overload on immune response

Increased susceptibility to infectious disease is observed in persons with transfusion-dependent thalassemia and iron overload who experience increased exposure to pathogens and chronic immune stimulation. An abnormal low CD8(+) T (LT8) immune phenotype defines a subgroup of patients. The CD8(+) T cell immunophenotype is stable despite continued blood transfusion and is independent of age. CD8(+) T cells, but not CD4(+) T cells, were modulated during intravenous chelation with deferoxamine. Return to characteristic pretreatment levels of CD8 was observed in both the low and the normal groups, suggesting the possibility of a set point. Proliferative response to mitogens and antigens was increased by chelation. Because CD8(+) T cells are important in immune response to infectious disease, these studies suggest that intrinsic CD8(+) T cell subset differences may be a critical factor in determining susceptibility to infection independent of transfusional iron overload or alloantigen exposure.

3'-Azido-3'-deoxythymidine reduces the rate of transferrin receptor endocytosis in K562 cells

K562 cells, exposed for at least 24 h to 5 microM 3'-azido-3'-deoxythymidine (AZT), gave rise to an overall increase in the number of cell surface transferrin binding receptors (18-20%). This effect was ascertained either with binding experiments by using 125I-transferrin and with immunoprecipitation by using a specific monoclonal antibody against the transferrin receptor. At higher AZT concentrations (20 and 40 microM), a further increase was found, that is, up to 23% by binding experiments and up to 110% by immunoprecipitation. However, Scatchard analysis of the binding data indicated that although the number of cell surface transferrin receptors increased, the affinity of transferrin for its receptor did not change (Ka=4.0x108 M). Surprisingly, immunoprecipitation of total receptor molecules showed that the synthesis of receptor was not enhanced by the drug treatment. The effect of AZT on transferrin internalization and receptor recycling was also investigated. In this case, data indicated that the increase in the number of receptors at the cell surface was probably due to a slowing down of endocytosis rate rather than to an increased recycling rate of the receptor to cell surface. In fact, the time during which half the saturated amount of transferrin had been endocytosed (t1/2) was 2.15 min for control cells and 3.41, 3.04, and 3.74 min for 5, 20, and 40 microM AZT-treated cells, respectively. Conversely, recycling experiments did not show any significant differences between control and treated cells. A likely mechanism through which AZT could interfere with the transferrin receptor trafficking, together with the relevance of our findings, is extensively discussed.

Pathogenesis and pathophysiology of anemia in HIV infection

Anemia is common in human immunodeficiency virus infection, particularly in patients with acquired immunodeficiency syndrome. Anemia is multifactorial. HIV infection itself causes anemia, probably as a consequence of HIV infection of stromal cells rather than HIV infection of hematopoietic stem cells. Other common causes of anemia in AIDS are anemia of chronic disease consequent on opportunistic infections, bone marrow suppression by antiretroviral therapy, and hemolytic anemia induced by oxidant drugs. Thrombotic microangiopathy is a significant complication of HIV infection and may respond to plasmapheresis.

Bone marrow macrophage iron grade and survival of HIV-seropositive patients

OBJECTIVE

Increased iron stores predispose to certain microbial infections. This association might be especially important in patients whose immune system is impaired by HIV. This study examined the relationship between iron stores and the survival times of patients with HIV infection.

DESIGN

Retrospective analysis of iron stores, as determined directly in bone marrow aspirates, and of hospital records.

SETTING

The George Washington University Hospital, an urban academic tertiary care institution.

PATIENTS

Three hundred and forty-eight HIV-seropositive adults who had diagnostic bone marrow aspirates between January 1985 and June 1996.

MEASUREMENTS

Bone marrow macrophage iron stores were graded on a scale of 0 to 5. For analysis of the influence of iron stores on survival, we compared patients with grades 4-5 iron stores (markedly or massively increased; n = 188) to those with grades 0-2 iron stores (normal or decreased; n = 130).

RESULTS

Infections caused by Candida spp., Pneumocystis carinii, and Mycobacterium spp. were more common in patients with high macrophage iron grades than in patients with low or normal iron grades (P < or = 0.006). The adjusted estimated rate of death (hazards ratio) was higher in patients with high iron stores compared with patients with low or normal iron stores, both from the time of the bone marrow study (ratio of 2.1; 95% confidence interval 1.3-3.5; P = 0.003) and the determination of HIV-seropositivity (ratio of 2.8; 95% confidence interval 1.4-4.9; P = 0.001).

CONCLUSION

High iron stores, as determined by bone marrow macrophage iron grade, may be associated with shorter survival times in patients with HIV infection.