The anaemia of infection

Myocardial Oedema as a Consequence of Viral Infection and Persistence-A Narrative Review with Focus on COVID-19 and Post COVID Sequelae

Microvascular integrity is a critical factor in myocardial fluid homeostasis. The subtle equilibrium between capillary filtration and lymphatic fluid removal is disturbed during pathological processes leading to inflammation, but also in hypoxia or due to alterations in vascular perfusion and coagulability. The degradation of the glycocalyx as the main component of the endothelial filtration barrier as well as pericyte disintegration results in the accumulation of interstitial and intracellular water. Moreover, lymphatic dysfunction evokes an increase in metabolic waste products, cytokines and inflammatory cells in the interstitial space contributing to myocardial oedema formation. This leads to myocardial stiffness and impaired contractility, eventually resulting in cardiomyocyte apoptosis, myocardial remodelling and fibrosis. The following article reviews pathophysiological inflammatory processes leading to myocardial oedema including myocarditis, ischaemia-reperfusion injury and viral infections with a special focus on the pathomechanisms evoked by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In addition, clinical implications including potential long-term effects due to viral persistence (long COVID), as well as treatment options, are discussed.

Toll-like Receptors as Pro-Thrombotic Drivers in Viral Infections: A Narrative Review

Toll-like receptors (TLRs) have a critical role in the pathogenesis and disease course of viral infections. The induced pro-inflammatory responses result in the disturbance of the endovascular surface layer and impair vascular homeostasis. The injury of the vessel wall further promotes pro-thrombotic and pro-coagulatory processes, eventually leading to micro-vessel plugging and tissue necrosis. Moreover, TLRs have a direct role in the sensing of viruses and platelet activation. TLR-mediated upregulation of von Willebrand factor release and neutrophil, as well as macrophage extra-cellular trap formation, further contribute to (micro-) thrombotic processes during inflammation. The following review focuses on TLR signaling pathways of TLRs expressed in humans provoking pro-thrombotic responses, which determine patient outcome during viral infections, especially in those with cardiovascular diseases.

Anemia in early congenital syphilis

The determination of blood parameters allowed us to establish that anemia develops in a number of infectious diseases, which is called "anemia of inflammation" or anemia of chronic diseases. The article presents a rare clinical case of the development of anemia of the inflammatory response, accompanied by a marked decrease in the content of hemoglobin (less than 110 g/l), hematocrit (less than 30%) and red blood cells (less than 3,0 х 1012/l), in a child with early congenital syphilis with symptoms of: specific rhinitis, papular infiltration, pemphigus, hepatosplenomegaly and damage to the nervous system. As a result of specific treatment with water-soluble benzylpenicillin salt at the rate of 100 U/kg of body weight for 28 days, and transfusion of erythrocyte mass of 15 ml/kg of child weight, there was a parallel regression of clinical manifestations of syphilis with positive dynamics of serological reactions and restoration of the number of red blood cells and the concentration of hemoglobin in the blood.

The effect of malaria on haemoglobin concentrations: a nationally representative household fixed-effects study of 17,599 children under 5 years of age in Burkina Faso

Background

Although the association between malaria and anaemia is widely studied in patient cohorts, the population-representative causal effects of malaria on anaemia remain unknown. This study estimated the malaria-induced decrease in haemoglobin levels among young children in malaria-endemic Burkina Faso.

Methods

The study was based on pooled individual-level nationally representative health survey data (2010–2011, 2014, 2017–2018) from 17 599 children under 5 years of age. This data was used to estimate the effects of malaria on haemoglobin concentration, controlling for household fixed-effects, age, and sex in a series of regression analyses. The fixed-effects controlled for observed and unobserved confounding on the household level and allowed to determine the impact of malaria infection status on haemoglobin levels and anaemia prevalence. Furthermore, the diagnostic results from microscopy and rapid diagnostic tests were leveraged to provide a quasi-longitudinal perspective of acute and prolonged effects after malaria infection.

Results

The prevalence of both malaria (survey prevalence ranging from 17.4% to 65.2%) and anaemia (survey prevalence ranging from 74% to 88.2%) was very high in the included surveys. Malaria was estimated to significantly reduce haemoglobin levels, with an overall effect of − 7.5 g/dL (95% CI − 8.5, − 6.5). Acute malaria resulted in a − 7.7 g/dL (95% CI − 8.8, − 6.6) decrease in haemoglobin levels. Recent malaria without current parasitaemia decreased haemoglobin concentration by − 7.1 g/dL (95% CI − 8.3, − 5.9). The in-sample predicted prevalence of severe anaemia was 9.4% among malaria positives, but only 2.2% among children without malaria.

Conclusion

Malaria infection has a strong detrimental effect on haemoglobin levels among young children in Burkina Faso. This effect seems to carry over even after acute infection, indicating prolonged haemoglobin reductions even after successful parasite-elimination. The quasi-experimental fixed-effect approach adds a population level perspective to existing clinical evidence.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-03948-z.

Association of serum selenium with anemia-related indicators and risk of anemia

Few studies have examined the association of serum selenium with anemia-related indicators and risk of anemia. We conducted a cross-sectional analysis of 2,902 adults in 2003-2004 National Health and Nutrition Examination Survey database. Multivariable linear and logistic regression models were used to examine the association of serum selenium with anemia-related indicators and risk of anemia. The nonlinear relationship was analyzed using a generalized additive model with the smoothing plot. A total of 1,472 males and 1,430 females with a mean age of 61.94 ± 13.73 years were included. Compared with the lowest quintile, the highest quintile of serum selenium was associated with increased level of serum iron (β = 12.44, 95% confidence interval [CI]: 7.14, 17.75, p < .001), mean corpuscular hemoglobin concentration (MCHC) (β = 0.14, 95%CI: 0.02, 0.26, p = .020), and hemoglobin (β = 0.40, 95%CI: 0.19, 0.61, p < .001), and decreased risk of anemia (odds ratio [OR] = 0.47, 95%CI: 0.28, 0.77, p = .002). Furthermore, smoothed plots suggested the nonlinear relationships between serum selenium and MCHC, hemoglobin level, and risk of anemia. Interestingly, on the left of inflection point, serum selenium was associated with decreased risk of anemia (OR = 0.972, 95%CI: 0.960, 0.985, p < .001), and then, the risk of anemia increased with increasing serum selenium concentration (OR = 1.011, 95%CI: 1.002, 1.021, p = .023). Future large-scale, polycentric prospective studies should be conducted to verify our results.

Schistosoma mansoni Infection Is Impacted by Malnutrition

Schistosomiasis remains one of the most important neglected tropical diseases in the world. It mainly affects developing countries, where it often coexists with malnutrition. Despite this, few studies have investigated the relationship between schistosomiasis and malnutrition. Herein, we evaluate the impact of malnutrition on experimental S. mansoni infection. Mice were divided into 5 groups: Control (Ctrl) diet (14% protein and 10% lipids), low-protein 3% (LP 3%), low-protein 8% (LP 8%), low-fat 2.5% (LF 2.5%), and low-fat 5% (LF 5%). Mice were fed with their respective diets and were infected when a difference of approximately 20% in the body weight between mice from any experimental group and mice from the control group was achieved. Nutritional, parasitological, and immunological parameters were assessed either just before infection and/or approximately 50 days later before mice were perfused. Our results showed that the 3% low-protein diet was the only one capable of establishing malnutrition in mice. Mice fed with this diet showed: (i) significant reduction in body weight and serum albumin levels before infection, (ii) decreased levels of all biochemical parameters evaluated before perfusion, (iii) decreased numbers of schistosome eggs trapped in intestines and impaired parasite fecundity, (iv) a delay in the granuloma development with a smaller granuloma area, and (v) reduced levels of IL-4 and IFN-γ in the liver. Our findings demonstrate that low protein supply leads to malnutrition in mice and impacts the cytokine milieu in the liver and granuloma formation. Additionally, the establishment of our murine malnutrition model will enable future studies aiming to better understand the complex relationships between nutrition, immune responses, and infection outcome.

Anaemia in asymptomatic parasite carriers living in urban, rural and peri-urban settings of Gabon

Background

This cross-sectional study was carried out in different settlements of Gabon to determine the influence of single or multiple parasite carriage on haemoglobin (Hb) levels.

Methods

Between April 2015 and June 2016, healthy volunteers from urban, peri-urban and rural areas were screened for malaria, blood filariasis and intestinal parasitic infections using microscopic methods. Hb concentration was measured with a Hemocue analyser. The association between parasite carriage and anaemia was assessed.

Results

Among the 775 volunteers examined, 319 (41.2%) were from rural villages and 76.0% were adults. Filariasis, intestinal parasitic infections, Plasmodium falciparum and polyparasitism were detected in 15.6, 14.6, 9.5 and 6.8% of participants, respectively. Anaemia prevalence was 72.6%, with rates of mild, moderate and severe anaemia being 30.9, 61.1 and 8.0%, respectively. The median Hb level was lowest in the presence of hookworms (7.1 g/dl [interquartile range {IQR} 6.8–7.5]), Schistosoma intercalatum (6.9 g/dl), Trichuris trichiura (10.1 g/dl [IQR 8.9–11.5]) and Plasmodium falciparum (10.0 g/dl [IQR 9.1–11.2]) compared with filariaemia (12.1 g/dl [IQR 10.5–13.2]) (p=0.03). Moderate to severe anaemia predominated among those single-infected with P. falciparum (69.5%) or co-infected with intestinal parasitic infections and P. falciparum (76.2%), while it was found in only 23.2% of individuals with filariasis. All participants with soil-transmitted helminths and more than half with a Blastocystis sp. (68.8%) infection had moderate anaemia.

Conclusions

The prevalence of anaemia is high. Asymptomatic parasite carriage is associated with anaemia in this surveyed population in Gabon.

Estimation of serum hepcidin in oral submucous fibrosis before and after supplementation with oral iron: A randomized control clinical trial

Background:

Iron-deficiency anemia is synonymous with oral submucous fibrosis (OSMF). The cause for the same has not been ascertained yet. OSMF by way of anemia of chronic disease could be a probable cause of iron deficiency.

Aim and Objective:

This study was intended to evaluate the level of hemoglobin (Hb) in OSMF and to establish a relationship between serum hepcidin and Hb with OSMF, before and after oral supplementation of iron.

Materials and Methods:

The clinical trial was registered with the Clinical Trial Registry of India (CTRI/2016/03/006761). Eighty participants were selected. Based on the hematocrit values, they were divided into equal number of case (Group I) and control (Group II). Serum hepcidin was evaluated in these eighty participants with clinically established OSMF. Participants in the case group with low hematocrit values indicative of iron-deficiency anemia were supplemented with oral iron capsules twice daily for 3 months. After an interval of 3 months, serum hepcidin and hematocrit were evaluated.

Statistics:

Statistical analysis was done using SPSS software version 11.5 (IBM, New York, USA). One-way ANOVA test was done to assess the correlation between Hb% and serum hepcidin. Unpaired t-test was done to correlate Hb% and hepcidin before and after oral supplementation of iron. Clinical significance was established by calculating the effect size.

Results:

There was a significant correlation between the values of serum hepcidin and Hb (P < 0.001) before and after oral supplementation of elemental iron. After oral supplementation of iron, hematocrit improved in Group I along with reduction in serum hepcidin.

Conclusion:

It can be concluded that reduction of serum hepcidin is indicative of improvement in iron stores of body. Hence, serum hepcidin can be utilized as a diagnostic marker to assess iron stores in OSMF.

Biomarkers of Nutrition for Development (BOND)-Iron Review

This is the fifth in the series of reviews developed as part of the Biomarkers of Nutrition for Development (BOND) program. The BOND Iron Expert Panel (I-EP) reviewed the extant knowledge regarding iron biology, public health implications, and the relative usefulness of currently available biomarkers of iron status from deficiency to overload. Approaches to assessing intake, including bioavailability, are also covered. The report also covers technical and laboratory considerations for the use of available biomarkers of iron status, and concludes with a description of research priorities along with a brief discussion of new biomarkers with potential for use across the spectrum of activities related to the study of iron in human health.The I-EP concluded that current iron biomarkers are reliable for accurately assessing many aspects of iron nutrition. However, a clear distinction is made between the relative strengths of biomarkers to assess hematological consequences of iron deficiency versus other putative functional outcomes, particularly the relationship between maternal and fetal iron status during pregnancy, birth outcomes, and infant cognitive, motor and emotional development. The I-EP also highlighted the importance of considering the confounding effects of inflammation and infection on the interpretation of iron biomarker results, as well as the impact of life stage. Finally, alternative approaches to the evaluation of the risk for nutritional iron overload at the population level are presented, because the currently designated upper limits for the biomarker generally employed (serum ferritin) may not differentiate between true iron overload and the effects of subclinical inflammation.

Anaemia control and the interpretation of biochemical tests for iron status in children

BACKGROUND

Anaemia is one of the world's most prevalent child health problems. Its control in Africa and other developing nations has been hindered by uncertainty regarding its cause. Anaemia control has been particularly problematic in regions where the non-iron deficiency causes of anaemia, are projected to be substantial. The implementation of effective interventions to reduce the anaemia prevalence, requires improved documentation on iron status and other causes of anaemia for target populations.

METHODS

This cross-sectional study enrolled n = 184 children, aged 6-8 years from Kwazulu-Natal, South Africa. Tests of haemoglobin, serum ferritin, soluble transferrin receptor and C-reactive protein were performed. These conventional measures of iron status were used to calculate body iron and to categorize the children into different groups of anaemia profiles.

RESULTS

Anaemia prevalence was high, 43/184 (23.4%). Iron deficiency anaemia contributed 7/43 (16.3%) to the anaemia prevalence compared to non-iron deficiency anaemia 34/43 (79.1%) and mixed anaemia 2/43 (4.7%). In total 47/184 (25.5%) of the sampled children had either iron deficiency or anaemia. Information about the presence of inflammation was used to adjust serum ferritin concentrations, resulting in improved diagnosis of iron deficiency.

CONCLUSION

Appropriate investigations for iron status and inflammation/infection screening, need to be integral in the evaluation of anaemia and its causes before anaemia control interventions are implemented. Interventions that target the multifactorial nature of anaemia in school-aged children need to be strengthened. Additionally, regular screening of anaemia in school-aged children from disadvantaged communities is recommended.

Serum Zinc Is a Major Predictor of Anemia and Mediates the Effect of Selenium on Hemoglobin in School-Aged Children in a Nationally Representative Survey in New Zealand

BACKGROUND

Zinc, selenium, and vitamin D status of New Zealand (NZ) school-aged children was examined in a national survey in 2002. To our knowledge, however, the role of these micronutrients as predictors of hemoglobin has not been explored despite plausible mechanisms for such relations.

OBJECTIVE

We examined the relations of iron, zinc, selenium, and vitamin D status with hemoglobin and anemia in children of New Zealand European and other (NZEO) ethnicity enrolled in the 2002 Children's Nutrition Survey and explored whether zinc mediated the relation between selenium and hemoglobin.

METHODS

Multivariate regression was performed to examine the relations of serum micronutrient biomarkers, acute inflammation, socioeconomic status, and body mass index (BMI) with hemoglobin and anemia of NZEO children aged 5-15 y (n = 503). A mediation analysis also investigated direct and indirect (through zinc) relations between selenium and hemoglobin.

RESULTS

In total, 4.6% of the children were anemic, 3.2% had depleted iron stores, and none had iron deficiency anemia. The prevalence of low serum zinc (<8.7-10.1 μmol/L depending on age and sex), selenium (<0.82 μmol/L), and 25-hydroxyvitamin D (<50 nmol/L) was 14.1%, 22.9%, and 48.5%, respectively. Major predictors of hemoglobin were serum zinc, age, and BMI-for-age z score (P < 0.001); log ferritin and being female were also statistically significant (P < 0.05). Selenium had an indirect effect that was mediated by zinc, with a significant effect of selenium on zinc (P = 0.002) and zinc on hemoglobin (P < 0.001). Zinc was the only variable associated with anemia risk (OR: 5.49; 95% CI: 1.95, 15.46).

CONCLUSIONS

Low serum zinc was an independent risk factor for anemia in NZEO school-aged children and mediated the effect of low selenium on hemoglobin. These findings emphasize the importance of considering multiple micronutrient deficiencies in addition to iron when interpreting anemia and of appreciating the mechanistic interactions that underlie these associations.

Infection-stimulated anemia results primarily from interferon gamma-dependent, signal transducer and activator of transcription 1-independent red cell loss

BACKGROUND

Although the onset of anemia during infectious disease is commonly correlated with production of inflammatory cytokines, the mechanisms by which cytokines induce anemia are poorly defined. This study focused on the mechanism research.

METHODS

Different types of mice were infected perorally with Toxoplasma gondii strain ME49. At the indicated times, samples from each mouse were harvested, processed, and analyzed individually. Blood samples were analyzed using a Coulter Counter and red blood cell (RBC) survival was measured by biotinylation. Levels of tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), and inducible protein 10 (IP-10) mRNA in liver tissue were measured by real-time polymerase chain reaction.

RESULTS

T. gondii-infected mice exhibited anemia due to a decrease in both erythropoiesis and survival time of RBC in the circulation (P < 0.02). In addition, infection-stimulated anemia was associated with fecal occult, supporting previous literature that hemorrhage is a consequence of T. gondii infection in mice. Infection-induced anemia was abolished in interferon gamma (IFNγ) and IFNγ receptor deficient mice (P < 0.05) but was still evident in mice lacking TNF-α, iNOS, phagocyte NADPH oxidase or IP-10 (P < 0.02). Neither signal transducer and activator of transcription 1 (STAT1) deficient mice nor 129S6 controls exhibited decreased erythropoiesis, but rather suffered from an anemia resulting solely from increased loss of circulating RBC.

CONCLUSIONS

Infection-stimulated decrease in erythropoiesis and losses of RBC have distinct mechanistic bases. These results show that during T. gondii infection, IFNγ is responsible for an anemia that results from both a decrease in erythropoiesis and a STAT1 independent loss of circulating RBC.

Maternal schistosomiasis: a growing concern in sub-Saharan Africa

Schistosomiasis remains one of the most important tropical parasitic infections threatening millions of lives in endemic areas. Cases of infections due to Schistosoma spp, the diecious digenetic trematodes have been on the increase over the last decades. While considerable efforts have been made to reduce infections and morbidities in most endemic areas, these efforts seem to be tailored only towards a specific group (school-based resources). This bias towards school children in epidemiological studies has also been observed in various research efforts in sub-Saharan Africa, thus making it difficult to produce a reliable estimate of the extent of infection in other strata of the population at risk. In recent times, attention has been drawn to Schistosoma spp infections in infants and preschool children, while studies on epidemiology of maternal schistosomiasis still suffer neglect. Considering the potential morbidity of Schistosoma infections on the mothers, fetuses, and neonates, as evidenced in some animal models and human case studies, more attention is solicited in all areas of observational studies and clinical trials, for maternal schistosomiasis with the aim of providing relevant data and information for effective management of the disease during pregnancy.

The regulation of iron metabolism in the mononuclear phagocyte system

The daily iron absorption and loss are small and iron metabolism in human is characterized by a limited external exchange and by an efficient reutilization of iron from internal sources. The mononuclear phagocyte system (MPS) plays a key role in recycling iron from hemoglobin of senescent or damaged erythrocytes, which is important in maintaining iron homeostasis. Many iron-related proteins are expressed in the MPS, including heme oxygenase (HO) for heme degradation, the iron importer transferrin receptor 1 (TfR1) and divalent metal transport 1 (DMT1), the iron exporter ferroportin 1 (FPN1) and the iron regulatory hormone hepcidin. Insights into the regulatory mechanisms that control the regulation of iron metabolism proteins in the MPS will deepen our understanding about the molecular mechanism of iron homeostasis and iron-related diseases.

Maternal Vitamin A Deficiency during Pregnancy and Its Relation with Maternal and Neonatal Hemoglobin Concentrations among Poor Egyptian Families

Background. Vitamin A deficiency (VAD) during pregnancy represents a major public health problem in developing countries. Anemia is a common consequence of VAD. We aimed to measure serum retinol concentrations of a sample of poor Egyptian mothers and correlate it with their Hb% and cord Hb%. Methods. This cross-sectional study included 200 healthy mothers and their healthy full term newborns. Maternal and cord blood samples were collected for CBC and measurement of serum retinol concentrations. Results. Forty-seven mothers (23.5%) had VAD and 50% were anemic. Mothers with VAD had a significantly lower mean Hb% and a significantly higher frequency of anemia (95.7%) compared to mothers without VAD (35.9%). The relative risk for anemia among mothers with VAD was 2.7 (CI = 2.12–3.3). Newborns of mothers with VAD had a significantly lower mean cord Hb% compared to newborns of mothers without VAD. Maternal serum retinol concentrations were positively correlated with maternal Hb% and cord Hb%. Conclusion. Maternal VAD during pregnancy among poor mothers is associated with maternal anemia and lower Hb% of newborns at birth. Vitamin A supplementation is highly recommended for this vulnerable group.

Spatial heterogeneity of haemoglobin concentration in preschool-age children in sub-Saharan Africa

OBJECTIVE

To determine whether blood haemoglobin concentration in preschool-age children (< 5 years of age) is geographically heterogeneous in sub-Saharan Africa and describe its association with environmental variables that drive anaemia of different etiologies.

METHODS

Data were obtained on 24 277 preschool-age children in western Africa (2862 cluster sites) and 25 343 in eastern Africa (2999 cluster sites) from the 2001-2007 Demographic and Health Surveys (DHS) for sub-Saharan Africa. Cluster sites were linked to environmental information on distance to perennial water body, elevation, land surface temperature and normalized difference vegetation index (NDVI; a proxy for rainfall) in a geographical information system. Statistical associations with environmental variables were determined using multivariate regression models, and the spatial dependence of haemoglobin concentration unexplained by these factors was quantified using semivariograms.

FINDINGS

In eastern Africa, the lowest haemoglobin concentrations (< 70 g/l) occurred in small clusters throughout the region; in western Africa, they occurred in a large cluster straddling the border between Burkina Faso and Mali. Our results show significant continent-wide associations between haemoglobin concentration and environmental variables, particularly in western Africa for land surface temperature and NDVI, and in eastern Africa for elevation. Residual spatial dependence was significant, and the magnitude was greater in western than in eastern Africa.

CONCLUSION

The distribution of anaemia is driven by large-scale environmental factors, and the epidemiological drivers differ in western and eastern Africa. Strategies for anaemia control in preschool-age children in sub-Saharan Africa should be tailored to local conditions, taking into account the specific etiology and prevalence of anaemia.

Mapping the risk of anaemia in preschool-age children: the contribution of malnutrition, malaria, and helminth infections in West Africa

BACKGROUND

Childhood anaemia is considered a severe public health problem in most countries of sub-Saharan Africa. We investigated the geographical distribution of prevalence of anaemia and mean haemoglobin concentration (Hb) in children aged 1-4 y (preschool children) in West Africa. The aim was to estimate the geographical risk profile of anaemia accounting for malnutrition, malaria, and helminth infections, the risk of anaemia attributable to these factors, and the number of anaemia cases in preschool children for 2011.

METHODS AND FINDINGS

National cross-sectional household-based demographic health surveys were conducted in 7,147 children aged 1-4 y in Burkina Faso, Ghana, and Mali in 2003-2006. Bayesian geostatistical models were developed to predict the geographical distribution of mean Hb and anaemia risk, adjusting for the nutritional status of preschool children, the location of their residence, predicted Plasmodium falciparum parasite rate in the 2- to 10-y age group (Pf PR(2-10)), and predicted prevalence of Schistosoma haematobium and hookworm infections. In the four countries, prevalence of mild, moderate, and severe anaemia was 21%, 66%, and 13% in Burkina Faso; 28%, 65%, and 7% in Ghana, and 26%, 62%, and 12% in Mali. The mean Hb was lowest in Burkina Faso (89 g/l), in males (93 g/l), and for children 1-2 y (88 g/l). In West Africa, severe malnutrition, Pf PR(2-10), and biological synergisms between S. haematobium and hookworm infections were significantly associated with anaemia risk; an estimated 36.8%, 14.9%, 3.7%, 4.2%, and 0.9% of anaemia cases could be averted by treating malnutrition, malaria, S. haematobium infections, hookworm infections, and S. haematobium/hookworm coinfections, respectively. A large spatial cluster of low mean Hb (<80 g/l) and maximal risk of anaemia (>95%) was predicted for an area shared by Burkina Faso and Mali. We estimate that in 2011, approximately 6.7 million children aged 1-4 y are anaemic in the three study countries.

CONCLUSIONS

By mapping the distribution of anaemia risk in preschool children adjusted for malnutrition and parasitic infections, we provide a means to identify the geographical limits of anaemia burden and the contribution that malnutrition and parasites make to anaemia. Spatial targeting of ancillary micronutrient supplementation and control of other anaemia causes, such as malaria and helminth infection, can contribute to efficiently reducing the burden of anaemia in preschool children in Africa.

Iron deficiency anemia: focus on infectious diseases in lesser developed countries

Iron deficiency anemia is thought to affect the health of more than one billion people worldwide, with the greatest burden of disease experienced in lesser developed countries, particularly women of reproductive age and children. This greater disease burden is due to both nutritional and infectious etiologies. Individuals in lesser developed countries have diets that are much lower in iron, less access to multivitamins for young children and pregnant women, and increased rates of fertility which increase demands for iron through the life course. Infectious diseases, particularly parasitic diseases, also lead to both extracorporeal iron loss and anemia of inflammation, which decreases bioavailability of iron to host tissues. This paper will address the unique etiologies and consequences of both iron deficiency anemia and the alterations in iron absorption and distribution seen in the context of anemia of inflammation. Implications for diagnosis and treatment in this unique context will also be discussed.

Recognising anaemia and malnutrition in vascular patients with critical limb ischaemia

INTRODUCTION

Anaemia is a common problem in surgical patients. Patients with critical limb ischaemia (CLI) suffer chronic inflammation, repeated infection, require intervention, and can have a protracted hospital stay. The aims of this study were to assess anaemia and nutritional status in patients presenting with CLI.

PATIENTS AND METHODS

Two observational studies were undertaken, initially a retrospective series of 27 patients with CLI. Patient demographics, clinical details, transfusion status and in-patient laboratory haemoglobin values (Hb) were recorded. In a prospective series of 32 patients, laboratory markers to identify the cause for anaemia were assessed. Further nutritional status was assessed by records of height, weight, body mass index and a validated scoring system.

RESULTS

In the retrospective series, 15 patients (56%) were anaemic. Ten (37%) were transfused a median of 2 units (range, 2-13), a total of 35 units. Patients who were transfused had lower Hb on admission (P = 0.0019), most were anaemic on admission (90%). At discharge, most patients were anaemic (n = 23; 83%). In the prospective series of 32 patients, 20 (63%) were anaemic. Nutritional assessment was performed on 18, only seven patients were scored undernourished. This was increased to 23 by an independent assessor. Anaemia was associated with malnutrition (n = 17; P = 0.049) and an increased hospital stay (mean 25 days [SD 16] vs mean 12 days [SD 8], P = 0.0125; total 513 vs 144 bed days).

CONCLUSIONS

Anaemia and poor nutrition are common and not recognised in vascular patients presenting with critical limb ischaemia. Anaemia is associated with and increased length of hospital stay.

Anemia of inflammation is related to cognitive impairment among children in Leyte, the Philippines

Background

Many studies have addressed the relationship between iron deficiency anemia (IDA) and cognitive impairment, but none have evaluated the role of non-iron deficiency anemia (NIDA). One of the main causes of NIDA in developing countries is AI, largely due to infectious diseases, whereby iron is shunted away from bio-available forms to storage forms, making it less accessible for use by host tissues. The objective of this study was to determine the effect of NIDA, due largely to AI in this context, on cognitive function after adjustment for potential confounders.

Methodology

This cross-sectional study was conducted in Leyte, The Philippines among 322 children ages 7–18 years. Blood samples were collected and analyzed at the time of cognition testing. Three stool samples were collected and evaluated by the Kato Katz method for quantitative assessment for Schistosoma japonicum and geo-helminth infection. Socio-economic status (SES) was evaluated by survey. Linear regression models were used to quantify the adjusted relationship between performance in different cognitive domains and both IDA and NIDA.

Principal Findings

After adjusting for age, sex, SES and nutritional status, children in the NIDA had lower scores on the PNIT (P = <0.05) and the WRAML memory domain (P<0.05) compared to children in the non-anemic group. Children in the IDA had lower performance on the PNIT compared to the non-anemic group after controlling for potential confounders (P<0.05).

Conclusions

NIDA, predominantly due to AI in this context, was related to lower performance on two tests of cognitive function. This is likely due to decreased delivery of iron to host tissues in this context, including the CNS.

Past studies have demonstrated that iron deficiency anemia is related to deficits in cognitive fucntioning in children, and treating iron deficiency anemia with iron supplementation can improve cognition. Anemia of inflammation is another type of anemia caused by many diseases of lesser-developed countries including bacterial and parasitic infections. Anemia of inflammation is characterized by disordered iron metabolism, such that iron is sequestered in storage forms, preventing its use from tissues that require it. We hypothesized that decreased iron delivery to the brain in the context of anemia of inflammation might lead to decreased cognitive performance. This study found that children with anemia of inflammation had decreased cognitive performance in specific domains, compared to subjects with no anemia. True total body iron deficiency anemia was related to lower performance in the same domains. The only treatment option for anemia of inflammation is treatment of the underlying disease. Iron supplementation will not prevent cognitive deficits in children with anemia of inflammation. Interventions aimed towards maximizing the cognitive development of children in lesser-developed countries will need to focus on the prevention and treatment of bacterial and parasitic infections.

Multiple micronutrients including iron are not more effective than iron alone for improving hemoglobin and iron status of Malian school children

Iron deficiency and anemia remain among the most important global public health problems facing school children. Helminth infections often peak at school age and aggravate nutritional risks. We conducted a 12-wk randomized controlled trial in 406 Malian anemic schoolchildren infected with Schistosoma hematobium to examine the effects of 2 doses of praziquantel (P) (40 mg/kg body weight), P + 60 mg/d iron (Fe), and/or a multiple micronutrient supplement (MM) that included 18 mg/d Fe. Supplements were administered to the children each school day (5 d/wk) throughout the study. Changes in hemoglobin (Hb), serum ferritin (SF), and serum transferrin receptors (s-TfR) were followed. We also examined interactions between Fe and MM supplements on Hb and SF concentrations and malaria incidence. The effects of Fe on Hb and SF concentrations were greater than the effects of P alone and MM with or without added Fe at 6 and 12 wk (P < 0.001). In all groups, s-TfR decreased at 6 and 12 wk compared with baseline. The decrease was most pronounced in the P + Fe group compared with the other 3 groups at wk 6 (P = 0.05). Fe and MM interacted negatively at wk 6 and 12 to affect Hb (beta = -0.43, 95% CI = -0.77, -0.09; P = 0.01 and beta = -0.47, 95% CI = -0.83, -0.11; P = 0.01, respectively) and SF (beta = -0.42, 95% CI = -25.60, 12.31; P < 0.001, and beta = -0.37, 95% CI = -0.63, -0.12; P = 0.004, respectively). Malaria incidence was higher in the groups treated with added Fe (relative risk: 1.66; 95% CI: 0.75, 3.67). In this context, MM with added iron were not more effective than Fe without MM. Fe supplementation of schoolchildren with 60 mg/d for anemia control should be considered carefully.

Haptoglobin halts hemoglobin's havoc

Hemoglobin (Hb) is crucial to the function of the red blood cell. However, when it is released during intravascular hemolysis from the cell into blood plasma, it produces a state of NO depletion, oxidant stress, and vascular dysfunction, including hypertension. In their study reported in this issue of the JCI, Boretti and colleagues used canine and guinea pig models to demonstrate that pharmacological doses of glucocorticoid can increase the plasma levels of haptoglobin (Hp), the principal plasma-binding protein for free Hb (see the related article beginning on page 2271). Hp prevented Hb-induced hypertension and the generation of oxidant damage to the kidney. Neutralization of free Hb appears to be part of the downstream antiinflammatory properties of glucocorticoid.

Hepcidin as a Predictor of Response to Epoetin Therapy in Anemic Cancer Patients

Background: Hepcidin is thought to be the central regulator of iron metabolism. Iron deficiency is associated with low hepcidin concentrations, and anemia in patients with cancer is associated with high concentrations of hepcidin.

Study objectives: Our main objective was to assess the potential role of hepcidin for predicting response to epoetin therapy in anemic cancer patients. We also aimed to identify a cutoff value for hepcidin as a potential predictive marker for response to epoetin therapy.

Methods: Using data from 525 anemic cancer patients enrolled in 5 studies, we assessed serum hepcidin concentrations in 408 of these patients at baseline and analyzed pooled data from the 408 patients. The analysis population was separated into 2 categories using a threshold hepcidin concentration of 13 nmol/L: low hepcidin (&lt;13 nmol/L) and high hepcidin (≥13 nmol/L).

Results: A significantly higher percentage of responders (defined as hemoglobin increase ≥10 g/L or ≥20 g/L from baseline) was observed in the low hepcidin group compared with the high hepcidin group (P = 0.04 for ≥10 g/L increase and P = 0.009 for ≥20 g/L from baseline). There was also a statistically significant difference between the 2 groups for hematopoietic response (hemoglobin rise at least once ≥20 g/L from baseline or at least once ≥120 g/L) to epoetin therapy (P = 0.0004).

Conclusions: The results of this analysis suggest a potential role of hepcidin serum concentrations in predicting the response to epoetin therapy.

BCG-malaria co-Infection has paradoxical effects on C57BL/6 and A/J mouse strains

Bacillus Calmette-Guérin (BCG) infection of the spleen is a potent modifier of splenic function. Prior to malaria infection, we infected two mouse strains of differing susceptibility to Plasmodium chabaudi AS (C57BL/6 and A/J) with this mycobacterium. We then evaluated aspects of spleen cell composition, architecture and cytokine expression, and correlated these with the outcome. BCG preinfection resulted in protection of the A/J mice but paradoxically resulted in mortality of the C57BL/6 mice. The latter developed higher parasitaemias that peaked earlier than the A/J mice rendered resistant by BCG. BCG infection induced remarkable changes to splenic histology examined by H&E staining, but there were no consistent differences between mouse strains. C57BL/6 mice had higher absolute numbers of all immune cell phenotypes than did A/J mice, and higher macrophage and dendritic cell proportions. BCG-induced resistance in A/J mice was associated with an increased CD4+ expression of IFN-gamma whilst induced death in C57BL/6 mice was associated with excessive IFN-gamma expression. A moderate TH1 response in the A/J model may have been responsible for the improved survival, and an excessive TH1 response in the C57BL/6 model may have contributed to their death.

Reticulocyte haemoglobin content vs. soluble transferrin receptor and ferritin index in iron deficiency anaemia accompanied with inflammation

Ferritin concentration, as a parameter of iron status that is commonly used in the diagnosis of iron deficiency anaemia (IDA), often has limited values if the iron deficiency is accompanied by inflammatory disease. This study evaluated the value of reticulocyte haemoglobin content (CHr) and soluble transferrin receptor-ferritin index (sTfR/F) in the diagnosis of IDA and differential diagnosis of IDA and anaemia of chronic disease. The study included 66 nonanaemic individuals as controls, 86 patients with IDA divided into noninflammatory and inflammatory subgroups, and 32 patients with anaemia of chronic disease. Blood count, iron, transferrin saturation, total iron binding capacity, ferritin, C-reactive protein, sTfR and CHr were determined. Receiver operator characteristic curve analysis showed very high discriminating power for CHr, soluble transferrin receptor (sTfR) and sTfR/F in the diagnosis of IDA. In patients with anaemia of chronic disease these parameters showed no significant difference from the control. CHr and sTfR enabled recognition of iron deficiency and were not affected by acute phase reaction. They are sensitive markers of body iron status with additional value to conventional tests for the detection of iron deficiency.

Hepcidin, a key regulator of iron metabolism, is transcriptionally activated by p53

Hepcidin is an iron-regulatory protein that is upregulated in response to increased iron or inflammatory stimuli. Hepcidin reduces serum iron and induces iron sequestration in the reticuloendothelial macrophages - the hallmark of anaemia of inflammation. Iron deprivation is used as a defense mechanism against infection, and it also has a beneficial effect on the control of cancer. The tumour-suppressor p53 transcriptionally regulates genes involved in growth arrest, apoptosis and DNA repair, and perturbation of p53 pathways is a hallmark of the majority of human cancers. This study inspected a role of p53 in the transcriptional regulation of hepcidin. Based on preliminary bioinformatics analysis, we identified a putative p53 response-element (p53RE) contained in the hepcidin gene (HAMP) promoter. Chromatin immunoprecipitation (ChIP), reporter assays and a temperature sensitive p53 cell-line system were used to demonstrate p53 binding and activation of the hepcidin promoter. p53 bound to hepcidin p53RE in vivo, andthis p53RE could confer p53-dependent transcriptional activation. Activation of p53 increased hepcidin expression, while silencing of p53 resulted in decreased hepcidin expression in human hepatoma cells. Taken together, these results define HAMP as a novel transcriptional target of p53. We hypothesise that hepcidin upregulation by p53 is part of a defence mechanism against cancer, through iron deprivation. Hepcidin induction by p53 might be involved in the pathogenesis of anaemia accompanying cancer.

Pathogenesis of anemia in malaria: a concise review

Anemia is a common complication in malarial infection, although the consequences are more pronounced with Plasmodium falciparum malaria (Ghosh, Indian J Hematol Blood Tranfus 21(53):128-130, 2003). Anemia in this infection is caused by a variety of pathophysiologic mechanisms, and in areas where malaria infection is endemic, co-morbidities like other parasitic infestations, iron, folate and Vitamin B12 deficiency, deficiency of other nutrients, and anemia, which is aggravated by anti-malarial drugs both through immune and non-immune mechanisms, are important considerations. In different endemic areas, beta-thalassemia, alpha-thalassemia, Hb S, Hb E, G6PD deficiency, or ovalocytosis in different proportions interact with this infection. Finally, aberrant immune response to repeated or chronic falciparum malarial infection may produce tropical splenomegaly syndrome, a proportion of which show clonal proliferation of B lymphocytes. Cooperation between chronic malarial infection and infection with E-B virus infection in producing Burkitt's lymphoma is well known. In this review, the fascinating and multifaceted pathophysiolgoy of malarial anemia has been discussed.

The effect of iron fortification and de-worming on anaemia and iron status of Vietnamese schoolchildren

Previous data from Vietnam show that anaemia is highly prevalent among schoolchildren, who are considered not to be iron deficient.Trichurisinfection doubled the risk of anaemia. The present study aimed to evaluate the hypothesis that de-worming is more effective than iron fortification in an anaemic, infection-prone population. In a trial with a 2 × 2 factorial design, 425 anaemic children aged 6–8 years were randomly assigned to receive either iron-fortified noodles or placebo, and mebendazole or placebo. Outcomes considered were change in haematological indicators of iron status (Hb, serum ferritin (SF), serum transferrin receptor (TfR) and haemoglobinopathies analysis); inflammations (C-reactive protein (CRP)); parasite infection status (hookworm,TrichurisandAscarisinfection); and IgE. ANOVA and logistic regression were used to assess the effects of iron fortification and de-worming on Hb, SF, TfR, body iron and anaemia. Hb improved in all groups after 6 months of intervention. Iron fortification significantly improved Hb, SF and body iron (2·6 g/l, 16·3 μg/l and 1 mg/kg, respectively). Prevalence of elevated IgE was very high at baseline (99 %) and significantly reduced to about 75 % in all groups after intervention. De-worming unexpectedly showed no effect on Hb, iron status and IgE level. It is concluded that iron fortification slightly improved anaemia and iron status in anaemic schoolchildren in rural Vietnam that were not considered iron deficient. Chronic infection or other unidentified factors may play an important role in the seasonal reduction of anaemia seen in all treatment groups.

Schistosomiasis and pregnancy

Currently, schistosomes infect approximately 40 million women of child-bearing age, yet little is known about schistosome-associated morbidity in pregnant women and their offspring. Animal models indicate a deleterious effect of schistosome infection on maternal, fetal and neonatal outcomes. Case reports have documented maternal infection in association with poor birth outcomes, and two observational studies indicate that maternal schistosome infection might be associated with decreased birth weight. Rigorously identifying and quantifying the impact of schistosome infection on pregnancy outcomes with well-designed observational and treatment studies are crucial for improving birth outcomes in schistosome-endemic areas. In addition, studies that address the safety of praziquantel during pregnancy could lead to further adoption of the recent informal recommendation by the World Health Organization to treat schistosome-infected pregnant and lactating women.

Hepcidin antimicrobial peptide transgenic mice exhibit features of the anemia of inflammation

The anemia of inflammation is an acquired disorder affecting patients with a variety of medical conditions, and it is characterized by changes in iron homeostasis and erythropoiesis. Mounting evidence suggests that hepcidin antimicrobial peptide plays a primary role in the pathogenesis of the anemia of inflammation. To evaluate which features of this anemia can be attributed to hepcidin, we have generated mice carrying a tetracycline-regulated hepcidin transgene. Expression of the hepcidin transgene resulted in down-regulation of endogenous hepcidin mRNA. The transgenic mice developed a mild-to-moderate anemia associated with iron deficiency and iron-restricted erythropoiesis. Similar to the anemia of inflammation, iron accumulated in tissue macrophages, whereas a relative paucity of iron was found in the liver. Circulating erythrocytes in transgenic animals had normal survival rates, but transgenic animals had an impaired response to erythropoietin. Thus, hepcidin transgenic mice recapitulate each of the key features of anemia of inflammation in human patients and serve as a useful model of this prevalent disorder.

Schistosoma japonicum reinfection after praziquantel treatment causes anemia associated with inflammation

There is a relationship between schistosomiasis and anemia, although the magnitude and exact mechanisms involved are unclear. In a cohort of 580 Schistosoma japonicum-infected 7- to 30-year-old patients from Leyte, The Philippines, we evaluated the impact of reinfection with S. japonicum after treatment with praziquantel on the mean hemoglobin level, iron-deficiency (IDA) and non-iron-deficiency anemia (NIDA), and inflammatory markers. All participants were treated at baseline and followed up every 3 months for a total of 18 months. At each follow-up, participants provided stools to quantify reinfection and venous blood samples for hemograms and measures of iron status and inflammation. After 18 months, reinfection with S. japonicum was associated with a lower mean hemoglobin level (-0.39 g/dl; 95% confidence interval [95% CI], -0.63 to -0.16) and 1.70 (95% CI, 1.10 to 2.61) times higher odds of all-cause anemia than those without reinfection. Reinfection was associated with IDA for high reinfection intensities only. Conversely, reinfection was associated with NIDA for all infection intensities. Reinfection was associated with serum interleukin-6 responses (P<0.01), and these responses were associated with NIDA (P=0.019) but not with IDA (P=0.29). Our results provide strong evidence for the causal relationship between S. japonicum infection and anemia. Rapidly reinfected individuals did not have the positive treatment effect on hemoglobin seen in nonreinfected individuals. The principle mechanism involved in S. japonicum-associated anemia is that of proinflammatory cytokine-mediated anemia, with iron deficiency playing a role in high-intensity infections. Based on the proposed mechanism, anemia is unlikely to be ameliorated by iron therapy alone.

Effect of maternal and neonatal vitamin A supplementation and other postnatal factors on anemia in Zimbabwean infants: a prospective, randomized study

BACKGROUND

Anemia is prevalent in infants in developing countries. Its etiology is multifactorial and includes vitamin A deficiency.

OBJECTIVE

Our primary aim was to measure the effect of maternal or neonatal vitamin A supplementation (or both) on hemoglobin and anemia in Zimbabwean infants. Our secondary aim was to identify the underlying causes of postnatal anemia.

DESIGN

A randomized, placebo-controlled trial was conducted in 14 110 mothers and their infants; 2854 infants were randomly selected for the anemia substudy, of whom 1592 were successfully observed for 8-14 mo and formed the study sample. Infants were randomly assigned within 96 h of delivery to 1 of 4 treatment groups: mothers and infants received vitamin A; mothers received vitamin A and infants received placebo; mothers received placebo and infants received vitamin A; and mothers and infants received placebo. The vitamin A doses were 400,000 and 50,000 IU in the mothers and infants, respectively.

RESULTS

Vitamin A supplementation had no effect on hemoglobin or anemia (hemoglobin <105 g/L) in unadjusted or adjusted analyses. Infant HIV infection independently increased anemia risk >6-fold. Additional predictors of anemia in HIV-negative and -positive infants were male sex and lower total body iron at birth. In addition, in HIV-positive infants, the risk of anemia increased with early infection, low maternal CD4+ lymphocyte count at recruitment, and frequent morbidity. Six-month plasma ferritin concentrations <12 microg/L were a risk factor in HIV-negative but not in HIV-positive infants. Maternal HIV infection alone did not cause anemia.

CONCLUSION

Prevention of infantile anemia should include efforts to increase the birth endowment of iron and prevent HIV infection.

Recombinant human erythropoietin therapy after allogeneic hematopoietic cell transplantation with a nonmyeloablative conditioning regimen: Low donor chimerism predicts for poor response

PURPOSE

After allogeneic hematopoietic stem cell transplantation with nonmyeloablative conditioning (NMHCT), many patients experience prolonged anemia and require red blood cell (RBC) transfusions. We enrolled 60 consecutive patients undergoing NMHCT in a phase II trial to determine the optimal utilization of recombinant human erythropoietin (rHuEPO) therapy in this setting.

PATIENTS AND METHODS

The first 14 NMHCT recipients did not receive rHuEPO (control group). Nineteen patients were scheduled to start rHuEPO on day 0 (EPO group 2) and 27 patients on day 28 after the transplant (EPO group 1). RHuEPO was administered subcutaneously once weekly at a dose of 500 U/kg/wk with the aim of achieving hemoglobin (Hb) levels of 13 g/dL. The 3 groups were well balanced for major characteristics.

RESULTS

During the first month (p < 0.0001) as well as days 30 to 100 (p < 0.0001) and days 100 to 180 (p < 0.0001), Hb values were higher in patients receiving rHuEPO compared to those not receiving it. However, transfusion requirements were significantly decreased only in the first month in EPO group 2 (p = 0.0169). T-cell chimerism above 60% on day 42 was the best predictor of Hb response (p < 0.0001) or Hb correction (p = 0.0217), but myeloid chimerism above 90% also predicted for Hb response (p = 0.0069). Hb response was also decreased in patients receiving CD8-depleted grafts and increased in the few patients not receiving TBI, but only in univariate analysis.

CONCLUSIONS

Anemia after NMHCT is sensitive to rHuEPO therapy, but less so than after conventional allogeneic HCT. RHuEPO decreases transfusion requirements only in the first 30 days posttransplant. T-cell chimerism below 60% on day 42 impaired Hb response, suggesting possible inhibition of donor erythropoiesis by residual recipient lymphocytes. A prospective randomized trial should be performed with rHuEPO starting on the day of transplantation to assess its clinical benefit in terms of transfusion requirements and quality of life.

Schistosomiasis japonica, anemia, and iron status in children, adolescents, and young adults in Leyte, Philippines 1

BACKGROUND

Observational and interventional evidence supports a relation between human schistosomiasis and anemia; however, the exact causal mechanisms remain unclear. Eggs translocating across the intestinal or bladder wall may result in extracorporeal blood loss with subsequent iron deficiency. Alternatively, anemia may result from cytokine-mediated dyserythropoiesis, as seen in anemia of inflammation.

OBJECTIVES

By evaluating the cross-sectional relation between the intensity of Schistosoma japonicum infection, hemoglobin concentration, and iron status in 7-30-y-old persons from S. japonicum-endemic rice-farming villages in the province of Leyte, Philippines, we assessed the relative contribution of iron deficiency and anemia of inflammation to schistosomiasis-associated anemia.

DESIGN

We enrolled 627 S. japonicum-infected and 111 S. japonicum-uninfected persons. We obtained stool samples to quantify S. japonicum infection and venous blood samples for hemograms and measures of iron status and inflammation.

RESULTS

Intensity of S. japonicum infection was independently associated with hemoglobin (beta = -0.24; 95% CI: -0.31, -0.17). Persons with high-intensity infection had a greater risk of iron deficiency anemia (adjusted prevalence odds ratio: 6.6; 95% CI: 2.9, 14.7), but there was no evidence of this relation in low-intensity infections. In contrast, anemia without iron deficiency was prevalent across all intensities (adjusted prevalence odds ratio: 3.8; 95% CI: 1.5, 9.5).

CONCLUSIONS

Storage iron deficiency is a major contributor to anemia in high-intensity S. japonicum infection. A high prevalence of anemia without iron deficiency, exclusion of other mechanisms of anemia, and the evidence of low bioavailable iron suggest that anemia of inflammation contributes to S. japonicum-associated anemia at all infection intensities.

Nutritional status improves after treatment of schistosoma japonicum-infected children and adolescents

Studies addressing the relation between chronic schistosomiasis japonica and nutritional status are limited. We conducted a longitudinal treatment-reinfection study in Leyte, the Philippines, among 477 Schistosoma japonicum-infected subjects aged 7-20 y, to evaluate changes in nutritional status after treatment with praziquantel. Stool, Tanner stage, anthropometric indices, and hemoglobin (Hb) were evaluated at baseline, 4 wk post-treatment, and every 3 mo for 18 mo. Height-for-age Z-score (HAZ) and BMI Z-score (BMIZ) were calculated. Change scores relative to baseline were created for all outcome measures. Multilevel repeated-measures analyses were used to adjust for socioeconomic status, sex, either pubertal status or age, and household-level clustering. Z-scores improved modestly but significantly over time. BMIZ in children wasted at baseline improved the most [0.41 (0.26-0.56) Z-score unit] and HAZ improved only in children stunted at baseline [0.17 (0.l2-0.21) Z-score unit]. Hb improvement peaked at 15 mo and occurred only in subjects that were anemic at baseline [peak improvement: 8.3 (6.0-10.6) g/L] and in males [peak improvement 4.7 (2.9-6.6) g/L]. Reinfection, evaluated as egg count over time and egg count 3 mo earlier to assess a delay in effect, was inversely associated with improvement in Hb (P = 0.06 and 0.004, respectively). High-intensity reinfection at 18 mo was associated with significantly less absolute growth from baseline compared with lower-intensity and no reinfection. Based on the peak Hb improvement at 15 mo post-treatment, annual treatment intervals are recommended to reduce schistosomiasis-associated nutritional morbidity.

Recent advances in understanding haemochromatosis: a transition state

Mutations in the hepcidin gene HAMP and the hemojuvelin gene HJV have recently been shown to result in juvenile haemochromatosis (JH). Hepcidin is an antimicrobial peptide that plays a key role in regulating intestinal iron absorption. Hepcidin levels are reduced in patients with haemochromatosis due to mutations in the HFE and HJV genes. Digenic inheritance of mutations in HFE and HAMP can result in either JH or hereditary haemochromatosis (HH) depending upon the severity of the mutation in HAMP. Here we review these findings and discuss how understanding the different types of haemochromatosis and our increasing knowledge of iron metabolism may help to elucidate the host's response to infection.

Anemia of inflammation: the hepcidin link

PURPOSE OF REVIEW

The anemia of inflammation has been associated for nearly two decades with elevated cytokine levels, but the primary mediator of this condition was unknown. Recently hepcidin antimicrobial peptide has emerged as the hormone that links the type II acute phase response to iron handling and erythropoiesis.

RECENT FINDINGS

Hepcidin antimicrobial peptide likely modulates iron transport from macrophages and enterocytes to red blood cell precursors as a consequence of its interaction with SLC40A1/ferroportin, the only known transporter that facilitates iron egress. Insights into the regulation of hepcidin antimicrobial peptide expression by known iron metabolic proteins such as HFE, hemojuvelin, and transferrin receptor 2 are expanding the understanding of the genetic circuitry that controls iron absorption and utilization.

SUMMARY

Increasingly, experiments suggest the hepatocyte is not just the iron storage depot but is the 'command central' for the maintenance of iron homeostasis. It receives multiple signals related to iron balance and responds via transcriptional control of hepcidin antimicrobial peptide.

Differential effects of virulent and avirulent equine infectious anemia virus on macrophage cytokine expression

Equine infectious anemia virus (EIAV) causes rapid development of acute disease followed by recurring episodes of fever, thrombocytopenia, and viremia. Most infected equid eventually bring the virus under immunological control. We recently reported the development of an equine-specific ribonuclease protection assay (RPA) to quantitate mRNA levels of 10 cytokines. Using this newly developed RPA, we now show significant differences in cytokine induction in equine monocyte-derived macrophages (EMDM) exposed to virulent and avirulent EIAV. Virulent EIAV17 induced significant increases in interleukin (IL)-1alpha, IL-1beta, IL-6, IL-10, and tumor necrosis factor (TNF)-alpha by 0.5-1 h postinfection (hpi). In contrast, the avirulent virus failed to induce any of the tested cytokines above that of control levels. These data show a direct correlation between cytokine dysregulation and EIAV pathogenesis.

Hemoglobin levels correlate with interleukin-6 levels in patients with advanced untreated epithelial ovarian cancer: role of inflammation in cancer-related anemia

Anemia occurs in more than 30% of patients with epithelial ovarian cancer before any surgery. High levels of proinflammatory cytokines and increased oxidative stress may contribute to the development of cancer-related anemia. We assessed a population of previously untreated patients with advanced epithelial ovarian cancer to evaluate whether there was a correlation between hemoglobin (Hb) and parameters of inflammation and oxidative stress, stage of disease, and performance status (PS). In 91 patients with epithelial ovarian cancer and 95 healthy women matched for age, weight, and height, levels of Hb, C-reactive protein (CRP), fibrinogen (Fbg), proinflammatory cytokines, leptin, reactive oxygen species (ROS), and antioxidant enzymes were assessed at diagnosis before treatment. The correlations between Hb, parameters of inflammation and oxidative stress, stage, and PS were evaluated. Hb levels were lower in patients with advanced epithelial ovarian cancer than in control subjects and inversely related to stage and PS. Hb negatively correlated with CRP, Fbg, interleukin 1beta (IL-1beta), IL-6, tumor necrosis factor alpha (TNFalpha), and ROS, and positively correlated with leptin and glutathione peroxidase (GPx). Multivariate regression analysis showed that stage and IL-6 were independent factors determining Hb values. This evidence suggests that anemia in epithelial ovarian cancer is common and its presence is related to stage of disease and markers of inflammation.

Malarial anaemia: mechanisms and implications of insufficient erythropoiesis during blood-stage malaria

It has been proposed that the basis of severe malarial anaemia, a major cause of morbidity and mortality in endemic areas, is multifactorial. Inappropriately low reticulocytosis is observed in malaria patients suggesting that insufficient erythropoiesis is a major factor. Clinical studies provide conflicting data concerning the production of adequate levels of erythropoietin (EPO) during malaria. Plasmodium chabaudi AS causes non-lethal infection in resistant C57BL/6 mice, and lethal infection in susceptible A/J mice. In P. chabaudi AS infected C57BL/6 and A/J mice, which experience varying degrees of severity of anaemia, kidney EPO production is appropriate to the severity of anaemia and is regulated by haematocrit level. Neutralisation of endogenous EPO during infection leads to lethal anaemia while timely administration of exogenous EPO rescues mice although reticulocytosis is suppressed in proportion to the parasitemia level. Characterisation of alterations in splenic erythroid compartments in naive and P. chabaudi AS infected A/J mice revealed that infection, with or without EPO treatment, leads to sub-optimal increases in TER119+ erythroblasts compared to EPO-treated naive mice. A lower percentage of TER119+ erythroblasts in infected mice undergo terminal differentiation to become mature haemoglobin-producing cells. Furthermore, there is a shift in transferrin receptor (CD71) expression from TER119+ cells to a non-erythroid population. Deficiencies in the number and maturation of TER119+ erythroblasts during infection coincide with blunted proliferation to EPO stimulation in vitro by splenocytes, although a high frequency express EPO receptor (EPOR). Together, these data suggest that during malaria, EPO-induced proliferation of early EPOR+ erythroid progenitors is suppressed, leading to sub-optimal generation of TER119+ erythroblasts. Moreover, a shift in CD71 expression may result in impaired terminal maturation of erythroblasts. Thus, suppressed proliferation, differentiation, and maturation of erythroid precursors in association with inadequate reticulocytosis may be the basis of insufficient erythropoiesis during malaria.

Vitamin A deficiency and inflammatory markers among preschool children in the Republic of the Marshall Islands

Background

The exclusion of individuals with elevated acute phase proteins has been advocated in order to improve prevalence estimates of vitamin A deficiency in surveys, but it is unclear whether this will lead to sampling bias. The purpose of the study was to determine whether the exclusion of individuals with elevated acute phase proteins is associated with sampling bias and to characterize inflammation in children with night blindness.

Methods

In a survey in the Republic of the Marshall Islands involving 281 children, aged 1–5 years, serum retinol, C-reactive protein (CRP), and α₁-acid glycoprotein (AGP) were measured.

Results

Of 281 children, 24 (8.5%) had night blindness and 165 (58.7%) had serum retinol <0.70 μmol/L. Of 248 children with AGP and CRP measurements, 123 (49.6%) had elevated acute phase proteins (CRP >5 mg/L and/or AGP >1000 mg/L). Among children with and without night blindness, the proportion with serum retinol <0.70 μmol/L was 79.2% and 56.8% (P = 0.03) and with anemia was 58.3% and 35.7% (P = 0.029), respectively. The proportion of children with serum retinol <0.70 μmol/L was 52.0% after excluding children with elevated acute phase proteins. Among children with and without elevated acute phase proteins, mean age was 2.8 vs 3.2 years (P = 0.016), the proportion of boys was 43.1% vs. 54.3% (P = 0.075), with no hospitalizations in the last year was 11.0% vs 23.6% (P = 0.024), and with anemia was 43.8% vs 31.7% (P = 0.05), respectively.

Conclusions

Exclusion of children with inflammation in this survey of vitamin A deficiency does not improve prevalence estimates for vitamin A deficiency and instead leads to sampling bias for variables such as age, gender, anemia, and hospitalization history.

Hepcidin, the recently identified peptide that appears to regulate iron absorption

A newly identified iron regulator, hepcidin, appears to communicate body iron status and demand for erythropoiesis to the intestine, and in turn, modulates intestinal iron absorption. Hepcidin was first purified from human blood and urine as an antimicrobial peptide and was found to be predominantly expressed in the liver. A lack of hepcidin expression has been associated with iron overload and overexpression of hepcidin results in iron-deficiency anemia in mice. In addition, hepcidin levels decrease in mice fed a low iron diet and increase in mice fed a high iron diet. These observations support the role of hepcidin as a signal that limits intestinal iron absorption. Hepcidin expression is also affected by hypoxia and inflammation and is decreased in hemochromatosis patients. Thus, the relationship between body iron status and hepcidin is altered in hemochromatosis patients. In addition, hepcidin is decreased in HFE knockout mice, which demonstrates characteristics of iron overload as in hemochromatosis patients. Hence, HFE is suggested to act as a regulator of hepcidin expression. Transcription factors, such as C/EBPalpha, are also suggested to be involved in the regulation of hepcidin gene expression. However, much remains to be investigated in the regulation of hepcidin by iron, hypoxia and inflammation.

Mutations in HFE2 cause iron overload in chromosome 1q-linked juvenile hemochromatosis

Juvenile hemochromatosis is an early-onset autosomal recessive disorder of iron overload resulting in cardiomyopathy, diabetes and hypogonadism that presents in the teens and early 20s (refs. 1,2). Juvenile hemochromatosis has previously been linked to the centromeric region of chromosome 1q (refs. 3-6), a region that is incomplete in the human genome assembly. Here we report the positional cloning of the locus associated with juvenile hemochromatosis and the identification of a new gene crucial to iron metabolism. We finely mapped the recombinant interval in families of Greek descent and identified multiple deleterious mutations in a transcription unit of previously unknown function (LOC148738), now called HFE2, whose protein product we call hemojuvelin. Analysis of Greek, Canadian and French families indicated that one mutation, the amino acid substitution G320V, was observed in all three populations and accounted for two-thirds of the mutations found. HFE2 transcript expression was restricted to liver, heart and skeletal muscle, similar to that of hepcidin, a key protein implicated in iron metabolism. Urinary hepcidin levels were depressed in individuals with juvenile hemochromatosis, suggesting that hemojuvelin is probably not the hepcidin receptor. Rather, HFE2 seems to modulate hepcidin expression.

2002 E. Mead Johnson Award for Research in Pediatrics Lecture: the molecular biology of the anemia of chronic disease: a hypothesis

The anemia of chronic disease is a common disorder that afflicts patients with a wide variety of inflammatory conditions including arthritis, malignancies, infections, and inflammatory bowel disease. It results in significant morbidity and may be severe enough to require blood transfusions. The pathogenesis of anemia of chronic disease is not fully understood, but poor maintenance of red blood cell mass has been observed at three levels: 1) iron is not efficiently recycled from reticuloendothelial macrophages to erythroid precursors, 2) erythroid precursors respond poorly to erythropoietin, and 3) red blood cell survival is decreased. Whether each of these changes is related to the same effector of the inflammatory process is unknown. We have had the opportunity to investigate severe anemia of chronic disease in an unusual group of patients with glycogen storage disease type 1a. We found that anemia was directly related to the presence of large hepatic adenomas that inappropriately produced a new peptide hormone, hepcidin. Hepcidin has recently been identified as part of the innate immune response and is a key regulator of cellular iron egress. Based on our findings in this patient group, we propose a central role for hepcidin in anemia of chronic disease, linking the inflammatory process with iron recycling and erythropoiesis. We present a hypothesis based on our findings.

Inappropriate expression of hepcidin is associated with iron refractory anemia: implications for the anemia of chronic disease

The anemia of chronic disease is a prevalent, poorly understood condition that afflicts patients with a wide variety of diseases, including infections, malignancies, and rheumatologic disorders. It is characterized by a blunted erythropoietin response by erythroid precursors, decreased red blood cell survival, and a defect in iron absorption and macrophage iron retention, which interrupts iron delivery to erythroid precursor cells. We noted that patients with large hepatic adenomas had severe iron refractory anemia similar to that observed in anemia of chronic disease. This anemia resolved spontaneously after adenoma resection or liver transplantation. We investigated the role of the adenomas in the pathogenesis of the anemia and found that they produce inappropriately high levels of hepcidin mRNA. Hepcidin is a peptide hormone that has been implicated in controlling the release of iron from cells. We conclude that hepcidin plays a major, causative role in the anemia observed in our subgroup of patients with hepatic adenomas, and we speculate that it is important in the pathogenesis of the anemia of chronic disease in general.

Prevalence and cumulative incidence of and risk factors for anemia in a multicenter cohort study of human immunodeficiency virus-infected and -uninfected women

We conducted a longitudinal study of 797 human immunodeficiency virus (HIV)-positive women (7732 visits) and 389 HIV-negative women (3651 visits) to characterize anemia. At enrollment, the prevalence of anemia was 28.1% among HIV-positive women and 15.1% among HIV-negative women (P<.0001), and during follow-up the cumulative incidence of anemia was 74% and 48%, respectively (P<.0001). Risk factors for anemia were African American race (odds ratio [OR], 2.15; 95% confidence interval [CI], 1.73-2.69), age (per 5-year increase; OR, 1.12; 95% CI, 1.03-1.21), body mass index (OR, 0.96; 95% CI, 0.94-0.97), history of pneumonia (OR, 1.41; 95% CI, 1.20-1.65), oral candidiasis (OR, 1.42; 95% CI, 1.22-1.66), CD4+ lymphocyte count <200 cells/microL (OR, 1.68; 95% CI, 1.46-1.94), history of fever (OR, 1.42; 95% CI, 1.13-1.80), and zidovudine use (OR, 1.14; 95% CI, 1.01-1.30). Anemia was common and associated with an increased risk of death (hazards ratio, 1.64; 95% CI, 1.21-2.23) among HIV-positive women.