Serum transferrin receptor in children and adolescents with inflammatory bowel disease

Reduced miR-513a-5p expression in COPD may regulate airway mucous cell hyperplasia through TFR1-dependent signaling

Airway mucous cell metaplasia and mucous hypersecretion is one of the key characteristic pathophysiological status of chronic obstructive pulmonary disease (COPD). micro(mi)RNAs are acknowledged as non-encoding RNA molecules playing important roles in gene expression regulation. In this study, we searched the Gene Expression Omnibus (GEO) database for the differentially expressed miRNAs between COPD and non-COPD controls with bioinformatics analysis. Finally, we focused on miR-513a-5p and investigated the potential mechanism by which miR-513a-5p regulates airway mucous hypersecretion and goblet cell metaplasia. A dual-luciferase reporter assay was then showing that miR-513a-5p targeted the 3'-UTR of TFR1 and inhibited its expression in vitro. In vivo transfection demonstrated that TFR1 downregulation partially blocked MUC5AC hypersecretion and goblet cell hyperplasia in COPD model rats. In vitro study, CSE increased the intracellular expression and secretion of MUC5AC by BEAS-2B branchial epithelial cells in the BEAS-2B cell and THP-1 cell coculture system. Coculture with either miR-513a-5p mimic-pretreated or TFR1-deficient THP-1 cells attenuated intracellular MUC5AC expression in BEAS-2B cells exposed to CSE. ELISA demonstrated that transfection of TFR1 siRNA or pretreatment with miR-513a-5p mimic reduced the secretion of inflammatory factors that are responsible for airway goblet cell hyperplasia, such as IL-1β, IL-13, and IL-17, by THP-1 cells after CSE stimulation. Our findings supported that miR-513a-5p/TFR1 signaling axis might activate macrophages as well as promote airway inflammation and airway mucous cell hyperplasia in COPD.

Anemia in Newly Diagnosed Pediatric Patients with Inflammatory Bowel Disease

Anemia is the most common extraintestinal manifestation and complication of inflammatory bowel disease (IBD). The aim of our study was to assess the prevalence of anemia in newly diagnosed pediatric patients with IBD and to analyze its association with disease type, extent, and severity. We retrospectively reviewed the medical records of all patients with IBD treated in our department in the period of November 2011 to November 2020. The final analysis included the records of 80 children with newly diagnosed IBD: 45 with ulcerative colitis (UC) and 35 with Crohn’s disease (CD). The prevalence of anemia was 60.0% in the UC patients and 77.1% in the CD patients. Of the UC patients with anemia, 37.1% had pancolitis, 18.5% extensive disease, 33.3% left-sided colitis and 11.1% ulcerative proctitis. Of the CD patients with anemia, 81.5% had ileocolonic disease, 11.1% colonic disease and 7.4% ileal disease. Anemia was less common in patients with mild disease than in patients with moderate–severe disease (22.2 vs. 77.8%, p < 0.001 in UC and 25.9% vs. 74.1%, p < 0.001 in CD). Our study confirmed anemia as a frequent problem in pediatric patients with IBD. Children with more extensive and more severe disease are at higher risk to develop anemia.

BODY IRON STATUS INDICATORS AND INFLAMMATION INDICATORS DURING INFLAMMATORY BOWEL DISEASE THERAPY IN CHILDREN AND ADOLESCENTES

BACKGROUND

The treatment of patients with inflammatory bowel disease (IBD) consists of the induction and maintenance remission of the disease. Iron status indicators would be useful for the diagnosis of iron deficiency anemia, whereas the inflammation indicators would be for the diagnosis of chronic disease anemia.

OBJECTIVE

To assess body iron status indicators and inflammation indicators during the treatment of IBD, consisted of conventional or infliximab therapy in children and adolescents.

METHODS

A case-control study of a sample of 116 individuals, of which 81 patients with IBD, 18 of them receiving conventional therapy, 20 infliximab therapy, and 43 who were in remission of the disease, and 35 healthy (control group) children and adolescents. Iron status and inflammation indicators were investigated at baseline, and 2 and 6 months of both therapies - conventional and infliximab.

RESULTS

The mean age was 12.1±4.3 years. At baseline, both groups - conventional therapy and infliximab - presented significant differences in most markers studied compared to the control group. After 2 months of conventional therapy, hemoglobin and serum iron levels were lower than those of the control group; and red cells distribution width (RDW), total iron-binding capacity, transferrin receptor/ferritin ratio, and interleukin-6 were higher than the control group. After 2 months of infliximab treatment, hemoglobin and serum iron levels were lower than those of the control group; and RDW, soluble transferrin receptor, soluble transferrin receptor/ferritin ratio, and interleukin-6 were higher than the control group. After 6 months of conventional therapy, hemoglobin and serum iron levels were lower than those of the control group, and RDW and interleukin-6 were higher than those of the control group. After 6 months of infliximab treatment, the hemoglobin and serum iron levels were lower than the control group, and RDW, soluble transferrin receptor, soluble transferrin receptor/ferritin ratio, erythrocyte sedimentation rate, and platelets were higher than the control group. Regarding patients under treatment for at least one year (remission group), all markers studied, except transferrin, were similar to the control group.

CONCLUSION

In conclusion, there were some contradictions among the different body iron status indicators and inflammation indicators at two and 6 months of treatment with conventional and infliximab therapy, however after one year of treatment, as shown by the remission group, all indicators studied, except transferrin, were similar to healthy children and adolescents.

Anemia in Children With Inflammatory Bowel Disease: A Position Paper by the IBD Committee of the North American Society of Pediatric Gastroenterology, Hepatology and Nutrition

Anemia is one of the most common extraintestinal manifestations of inflammatory bowel disease (IBD). It can be asymptomatic or associated with nonspecific symptoms, such as irritability, headaches, fatigue, dizziness, and anorexia. In IBD patients, the etiology of anemia is often multifactorial. Various causes include iron deficiency, anemia of inflammation and chronic disease, vitamin deficiencies, hemolysis, or myelosuppressive effect of drugs. Anemia and iron deficiency in these patients may be underestimated because of their insidious onset, lack of standardized screening practices, and possibly underappreciation that treatment of anemia is also required when treating IBD. Practitioners may hesitate to use oral preparations because of their intolerance whereas intravenous preparations are underutilized because of fear of adverse events, availability, and cost. Several publications in recent years have documented the safety and comparative efficacy of various intravenous preparations. This article reviews management of anemia in children with IBD, including diagnosis, etiopathogenesis, evaluation of a patient, protocol to screen and monitor patients for early detection and response to therapy, treatment including parenteral iron therapy, and newer approaches in management of anemia of chronic disease. This report has been compiled by a group of pediatric gastroenterologists serving on the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) IBD committee, in collaboration with a pediatric hematologist, pharmacist, and a registered dietician who specializes in pediatric IBD (IBD Anemia Working Group), after an extensive review of the current literature. The purpose of this review is to raise awareness of under-diagnosis of anemia in children with IBD and make recommendations for screening, testing, and treatment in this population.

Comparative accuracy of ferritin, transferrin saturation and soluble transferrin receptor for the diagnosis of iron deficiency in inflammatory bowel disease

BACKGROUND

The diagnosis of iron deficiency is based on ferritin and transferrin saturation (TfS) in inflammatory bowel disease (IBD) patients, yet guideline thresholds are not evidence-based. Soluble transferrin receptor (sTfR) is one of the best noninvasive tests in patients with inflammation.

AIMS

To evaluate the accuracy of ferritin and/or TfS for diagnosing iron deficiency in IBD and identify the optimal thresholds of these parameters using sTfR as reference.

METHODS

Two hundred and two patients (2072 samples) receiving at least one infusion of biologic (vedolizumab or infliximab) were included.

RESULTS

In ulcerative colitis patients with C-reactive protein (CRP) <10 mg/L, optimal iron deficiency diagnostic performances were observed with ferritin and TfS thresholds of 65 µg/L (sensitivity of 0.78 and specificity of 0.76) and 16% (sensitivity of 0.79 and specificity of 0.90), respectively. For ulcerative colitis patients with CRP > 10 mg/L, the thresholds with the best diagnostic performance were 80 µg/L (sensitivity of 0.75 and a specificity of 0.82) for ferritin and 11% for TfS (sensitivity of 0.75 and a specificity of 0.82). There was no added value for combined ferritin and TfS. No ferritin or TfS threshold had good diagnostic performance in Crohn's disease patients (AUC for ferritin was 0.65 (95% CI 0.55-0.75) and the AUC for TfS was 0.70 (95% CI 0.61-0.78).

CONCLUSION

Ferritin and TfS are reliable parameters for iron deficiency diagnosis only in ulcerative colitis patients, at thresholds different from current guidelines. In Crohn's disease patients, sTfR should be used given the poor diagnostic performance of ferritin and TfS.

Biomarkers and Hematological Indices in the Diagnosis of Iron Deficiency in Children with Inflammatory Bowel Disease

Inflammation may affect many routinely available parameters of iron homeostasis. Thus, the recognition of iron deficiency in inflammatory bowel disease (IBD) remains a diagnostic challenge in a clinical routine. The aim of the study was to detect the most efficient marker of iron deficiency in IBD children. In a group of 75 IBD children, we evaluated the sensitivity, specificity, accuracy, and positive and negative predictive values of erythrocytes' indices, including MCV, MCH, MCHC and RDW, and biochemical markers, including iron, transferrin, sTfR and sTfR/log ferritin, for identifying iron deficiency. Receiver operating characteristic (ROC) analysis was used to compare the ability of these parameters to detect iron deficiency. The best predictors of iron deficiency were sTfR/log ferritin, with accuracy 0.86, sensitivity 0.98, specificity 0.63, positive predictive value 0.83 and negative predictive value 0.94, and sTfR, with accuracy 0.77, sensitivity 0.82, specificity 0.67, positive predictive value 0.82 and negative predictive value 0.67. Moreover, sTfR/log ferritin exhibited the largest area under ROC (0.922), followed by sTfR (0.755) and MCH (0.720). The sTfR/log ferritin index appears to be the most efficient marker of iron depletion in pediatric IBD, and it may give an added value in the management of IBD patients.

A Cross-Sectional Study on Malnutrition in Inflammatory Bowel Disease: Is There a Difference Based on Pediatric or Adult Age Grouping?

BACKGROUND

Malnutrition, commonly observed in inflammatory bowel disease (IBD), is associated with increased morbidity and mortality and is attributed to multiple causes. The added energy costs of growth in the child and adolescent with IBD are an additional risk factor.

METHODS

The aim of the study was to perform a cross-sectional comparison of nutritional parameters in IBD between pediatric and adult cases.

RESULTS

We found that prevalence of undernutrition (low body mass index) and hypoalbuminemia was not different in pediatric, compared with adult patients. Anemia and iron deficiency were more often observed in pediatric subjects, compared with adults (59.1% vs 36.9%, respectively, P < 0.0001; and 37.9% vs 25.3%, P < 0.002). Vitamin B12 deficiency was significantly less common in the pediatric than in the adult group (5.4% vs 19.4%, P < 0.0001). Elevated C-reactive protein was more frequent in pediatric compared with adult cases (49.8% vs 38.4%, P < 0.01).

CONCLUSIONS

Patients with active Crohn's disease were more likely to be undernourished in both pediatric and adult populations. In both groups, predicators of undernutrition included low albumin levels (odds ratio [OR], 2.53; P < 0.006) and active disease (OR, 1.99; P < 0.03). Our results call for close surveillance of nutritional status for IBD patients, regardless of age.

Anemia Screening, Prevalence, and Treatment in Pediatric Inflammatory Bowel Disease in the United States, 2010-2014

PURPOSE

We examined the prevalence of anemia, annual screening for anemia, and treatment of anemia with iron among children with inflammatory bowel disease (IBD).

METHODS

A retrospective study of U.S. pediatric patients with IBD was performed in the MarketScan commercial claims database from 2010-2014. Children (ages 1-21) with at least two inpatient or outpatient encounters for IBD who had available lab and pharmacy data were included in the cohort. Anemia was defined using World Health Organization criteria. We used logistic regression to determine differences in screening, incident anemia, and treatment based on age at first IBD encounter and sex.

RESULTS

The cohort (n=2,446) included 1,560 Crohn's disease (CD) and 886 ulcerative colitis (UC). Approximately, 85% of CD and 81% of UC were screened for anemia. Among those screened, 51% with CD and 43% with UC had anemia. Only 24% of anemia patients with CD and 20% with UC were tested for iron deficiency; 85% were iron deficient. Intravenous (IV) iron was used to treat 4% of CD and 4% UC patients overall and 8% of those with anemia.

CONCLUSION

At least 80% of children with IBD were screened for anemia, although most did not receive follow-up tests for iron deficiency. The 43%-50% prevalence of anemia was consistent with prior studies. Under-treatment with IV iron points to a potential target for quality improvement.

Soluble transferrin receptor and soluble transferrin receptor/log ferritin index in diagnosis of iron deficiency anemia in pediatric inflammatory bowel disease

BACKGROUND

There is no single reliable marker of iron homeostasis in inflammatory bowel disease.

AIMS

To determine diagnostic usefulness of soluble transferrin receptor and soluble transferrin receptor/log ferritin index in iron deficiency anemia in children with inflammatory bowel disease.

METHODS

We assessed soluble transferrin receptor in serum and calculated soluble transferrin receptor/log ferritin index in 75 children with inflammatory bowel disease. Diagnostic ability to identify iron deficiency anemia was examined by receiver operating characteristic analysis.

RESULTS

Study group comprised 27 cases of iron deficiency anemia, 6 anemia of chronic disease with iron deficiency, 5 anemia of chronic disease. Soluble transferrin receptor was significantly increased in children with iron deficiency anemia (median: 1.63 μg/ml) compared to non-anemic children (median: 1.02 μg/ml). Soluble transferrin receptor/log ferritin index was significantly higher in iron deficiency anemia (median: 1.76) than in anemia of chronic disease (median: 0.55), anemia of chronic disease with iron deficiency (median: 0.68) or patients without anemia (median: 0.72). Soluble transferrin receptor and its index were not correlated with disease activity or inflammatory markers. Diagnostic power for soluble transferrin receptor/log ferritin index (0.864) was superior to soluble transferrin receptor (0.768) in iron deficiency anemia recognition.

CONCLUSION

Soluble transferrin receptor/log ferritin index has better diagnostic utility than soluble transferrin receptor for iron deficiency anemia detection in pediatric inflammatory bowel disease.

A Systematic Review of Micronutrient Deficiencies in Pediatric Inflammatory Bowel Disease

BACKGROUND

This systematic review critically analyzes the current research on micronutrient deficiency in children with inflammatory bowel disease (IBD) and synthesizes these data to provide evidence-based guidelines for nutritional surveillance in this population.

METHODS

We searched 5 databases (Ovid Medline, PubMed, Scopus, CINAHL, and Cochrane Library) for studies evaluating micronutrients in patients with IBD using the following inclusion criteria: 1) original research, 2) published 1996 or later; 3) published in English; 4) human subjects; and 5) containing pediatric data. Studies were reviewed and included based on the strength of research methods. Data on the prevalence of micronutrient deficiencies in pediatric patients with IBD and risk factors for micronutrient deficiency in these patients were extracted from included studies and compared and discussed in preparation of the proposed guidelines and manuscript.

RESULTS

A total of 39 studies were included in the final review. The data presented in these studies show that iron deficiency and vitamin D deficiency are common in pediatric patients with IBD. Vitamin B12 and folate deficiency are rare. Zinc deficiency, while not common, occurs at a higher rate in patients with Crohn's disease than in healthy controls. There was limited data on vitamins A, E, and C, and selenium, but deficiency of these micronutrients seems rare.

CONCLUSIONS

We recommend annual surveillance of iron and vitamin D in pediatric patients with IBD regardless of disease activity or phenotype. Zinc should be monitored annually in patients with Crohn's disease. There is insufficient evidence to support routine screening for other micronutrient deficiencies.

Proteomic analysis of ascending colon biopsies from a paediatric inflammatory bowel disease inception cohort identifies protein biomarkers that differentiate Crohn's disease from UC

OBJECTIVE

Accurate differentiation between Crohn's disease (CD) and UC is important to ensure early and appropriate therapeutic intervention. We sought to identify proteins that enable differentiation between CD and UC in children with new onset IBD.

DESIGN

Mucosal biopsies were obtained from children undergoing baseline diagnostic endoscopy prior to therapeutic interventions. Using a super-stable isotope labeling with amino acids in cell culture (SILAC)-based approach, the proteomes of 99 paediatric control and biopsies of patients with CD and UC were compared. Multivariate analysis of a subset of these (n=50) was applied to identify novel biomarkers, which were validated in a second subset (n=49).

RESULTS

In the discovery cohort, a panel of five proteins was sufficient to distinguish control from IBD-affected tissue biopsies with an AUC of 1.0 (95% CI 0.99 to 1.0); a second panel of 12 proteins segregated inflamed CD from UC within an AUC of 0.95 (95% CI 0.86 to 1.0). Application of the two panels to the validation cohort resulted in accurate classification of 95.9% (IBD from control) and 80% (CD from UC) of patients. 116 proteins were identified to have correlation with the severity of disease, four of which were components of the two panels, including visfatin and metallothionein-2.

CONCLUSIONS

This study has identified two panels of candidate biomarkers for the diagnosis of IBD and the differentiation of IBD subtypes to guide appropriate therapeutic interventions in paediatric patients.

Iron Deficiency in Inflammatory Bowel Disease: The Use of Zincprotoporphyrin and Red Blood Cell Distribution Width

OBJECTIVES

Iron deficiency (ID) in children with inflammatory bowel disease (IBD) is either an absolute (depleted iron stores) or a functional deficiency (caused by chronic inflammation). Differentiating between these 2 types of ID is important because they require a different therapeutic approach. Zinc protoporphyrin (ZPP) and red blood cell distribution width (RDW) are parameters of functional ID. Studies using these parameters to differentiate are nonexistent. We aimed to evaluate the prevalence of and risk factors for absolute and functional ID in paediatric IBD patients while using ZPP and RDW.

METHODS

We evaluated the iron status and medical charts of 59 paediatric IBD patients in a secondary hospital in the Netherlands. Absolute ID was defined as serum ferritin <15 μg/L in the absence of infection and/or acute inflammation (C-reactive protein <10 mg/L). Iron deficiency anaemia (IDA) was defined as absolute ID in combination with anaemia. Functional ID, in patients without absolute ID, was defined as ZPP >70 μmol/mol haem and/or an RDW >14%. Anaemia of chronic disease (ACD) was defined as functional ID in combination with anaemia.

RESULTS

Absolute and functional ID were found in 19/59 (32.2%) and 32/40 (80%) patients, respectively. The prevalence of IDA and ACD was 27.1% (16/59) and 20% (8/40), respectively. Multivariate analyses showed that absolute ID and IDA were both associated with a more recent IBD-diagnosis (both P < 0.05).

CONCLUSIONS

Absolute and functional ID are common in paediatric IBD patients, and this differentiation is important because of therapeutic consequences. Furthermore, absolute ID and IDA are associated with a more recent IBD-diagnosis.

Iron Deficiency Is Common During Remission in Children With Inflammatory Bowel Disease

The aim was to study prevalence of iron deficiency in children with inflammatory bowel disease (IBD) during remission. In addition, there was an observational evaluation of hematological response to oral iron. A population-based retrospective study including 90 Swedish children (median 13 years) with IBD was performed. Patient records covered in median 25 months. Iron deficiency was present in 70/77 children (91%) in which iron status could be assessed. In clinical and biochemical remission, iron deficiency was found in 57/67 (85%) of children, and 23 (34%) of them had iron deficiency anemia. Thirty-six iron-deficient children were prescribed oral iron supplementation and 32 (89%) improved hemoglobin levels over 6 months. In conclusion, iron deficiency is common during clinical remission in children with IBD, even in cohorts with low prevalence of anemia. Therefore, regular biochemical screening for iron deficiency is warranted during all stages of disease, irrespective of symptoms and inflammatory blood markers.

The epidemiology of anemia in pediatric inflammatory bowel disease: prevalence and associated factors at diagnosis and follow-up and the impact of exclusive enteral nutrition

BACKGROUND

Anemia is poorly studied in pediatric inflammatory bowel disease. This study explored the epidemiology and associated factors of anemia at diagnosis, after 1 year, and during treatment with exclusive enteral nutrition (EEN).

METHODS

Three cohorts were included: (1) a representative population of newly diagnosed inflammatory bowel disease children (n = 184); (2) patients currently receiving care with data available at diagnosis (n = 179) and after 1 year (n = 139); and (3) 84 children treated with EEN.

RESULTS

At diagnosis, 72% were anemic. Abnormal inflammatory markers were more common in Crohn's disease with severe anemia (severe versus no anemia [%]: raised C-reactive protein; 89% versus 48%; suboptimal albumin; 97% versus 29%; P < 0.002). Anemic children with Crohn's disease had shorter diagnosis delay and lower BMI than nonanemic patients (severe versus mild versus no anemia, median [interquartile range]; diagnosis delay [months]: 3 [3.9] versus 6 [10] versus 8 [18], P < 0.001; BMI z score [SD]: -1.4 [1.4] versus -1.3 [1.5] versus -0.2 [1.4], P = 0.003). Extensive colitis was associated with severe anemia in ulcerative colitis. The proportion of severely anemic patients decreased from 34% to 9% and mild anemia doubled at 1 year. After EEN, severe anemia decreased (32% to 9%; P < 0.001) and the hemoglobin concentration increased by 0.75 g/dL. This was observed only after 8 weeks of treatment. Disease improvement and low hemoglobin at EEN initiation but not weight gain were associated with hemoglobin improvement.

CONCLUSIONS

Anemia is high at diagnosis and follow-up and should receive more attention from the clinical team; however, the focus should remain suppression of inflammatory process in active disease.

Is iron deficiency in the absence of anemia associated with fatigue in inflammatory bowel disease?

OBJECTIVES

We explored whether iron deficiency in the absence of anemia is associated with fatigue in inflammatory bowel disease (IBD).

METHODS

We assessed iron deficiency and anemia in 280 participants from the population-based Manitoba IBD Cohort Study.

RESULTS

Iron deficiency was identified in 20% with Crohn's disease and 27% with ulcerative colitis. Anemia was identified overall in 50 (18%), with 230 who were nonanemic. In the nonanemic subgroup, there were no significant differences between iron-deficient and -sufficient groups in mean fatigue levels or proportions with problematic fatigue. There was no unique contribution of iron deficiency to problematic fatigue after adjustment for active disease and anemia.

CONCLUSIONS

There was no evidence of an association between iron deficiency and fatigue in the absence of anemia, suggesting that iron deficiency is not a clinically relevant contributor to fatigue in IBD.

Impact of exclusive enteral nutrition on body composition and circulating micronutrients in plasma and erythrocytes of children with active Crohn's disease

BACKGROUND

Nutritional therapy is the primary treatment for active pediatric Crohn's disease (CD) in the UK/Europe, improving disease activity and anthropometry. This study assessed changes in micronutrient status during exclusive enteral nutrition (EEN).

METHODS

Seventeen children (male/female: 8/9; median age: 12.7 years) with active CD were treated exclusively for 6-8 weeks on a polymeric feed (Modulen IBD; Nestle, UK). Body impedance was measured at baseline, during EEN, and posttreatment on normal diet and converted to z-scores of fat and lean mass. Blood samples for nutrient analysis were collected from 13 children at baseline, end of EEN, and posttreatment.

RESULTS

Lean but not fat mass improved at the end of EEN (initiation vs. end of EEN; fat mass [z-score]: -0.5 vs. -0.3; P = 0.141; lean mass [z-score]: -2.1 vs. -0.8; P < 0.0001). At baseline several children presented with suboptimal concentrations of carotenoids, trace elements, vitamin C, B6, and folate in plasma but not in erythrocytes. EEN improved concentrations for several nutrients, but more than 90% of patients had depleted concentrations of all carotenoids. The latter improved on normal diet but other micronutrients, which improved during EEN, returned toward pretreatment concentrations.

CONCLUSIONS

Lean but not fat mass improved at the end of EEN. Median concentrations for several plasma micronutrients improved on EEN but carotenoids were depleted. These findings may have implications for clinical practice and producers of enteral feeds. As plasma concentrations for many micronutrients can be affected by the acute phase response, measurements in erythrocytes may be a better marker of actual body stores.

Anaemia and iron deficiency in children with inflammatory bowel disease

BACKGROUND AND AIMS

Anaemia and iron deficiency are common in children with Inflammatory Bowel Disease (IBD) however it is not known if the prevalence of anaemia and iron deficiency alters following diagnosis.

METHODS

Laboratory results from diagnosis, and at follow up one and two years later were recorded retrospectively in children with IBD recruited from a tertiary centre. Anaemia was defined using WHO standards and iron deficiency defined using published guidelines.

RESULTS

46 children (16 girls) with Crohn's disease and 34 children (18 girls) with UC were studied. 75% of children with IBD were anaemic at diagnosis, 30% were anaemic at follow up two years later. 90% of children with Crohn's and 95% of children with Ulcerative Colitis (UC) were iron deficient at diagnosis. At follow up two years later 70% of children with Crohn's and 65% of children with UC were iron deficient.

CONCLUSIONS

Persistent anaemia and iron deficiency are common in childhood IBD, prevalence alters with duration of time from diagnosis.

Prevalence and management of anemia in children, adolescents, and adults with inflammatory bowel disease

BACKGROUND

Children and adolescents with inflammatory bowel disease (IBD) are more likely to have Crohn's disease (CD) than ulcerative colitis (UC) and their disease tends to be more extensive and severe than in adults. We hypothesized that the prevalence of anemia would therefore be greater in children and adolescents than in adults attending IBD outpatient clinics.

METHODS

Using the WHO age-adjusted definitions of anemia we assessed the prevalence, severity, type, and response to treatment of anemia in patients attending pediatric, adolescent, and adult IBD clinics at our hospital.

RESULTS

The prevalence of anemia was 70% (41/59) in children, 42% (24/54) in adolescents, and 40% (49/124) in adults (P < 0.01). Overall, children (88% [36/41]) and adolescents (83% [20/24]) were more often iron-deficient than adults (55% [27/49]) (P < 0.01). Multivariate logistic regression showed that both active disease (odds ratio [OR], 4.7 95% confidence interval [CI], 2.5, 8.8) and attending the pediatric clinic (OR 3.7; 95% CI, 1.6, 8.4) but not the adolescent clinic predicted iron deficiency anemia. Fewer iron-deficient children (13% [5/36]) than adolescents (30% [6/20]) or adults (48% [13/27]) had been given oral iron (P < 0.05); none had received intravenous iron compared with 30% (6/20) adolescents and 41% (11/27) adults (P < 0.0001).

CONCLUSIONS

Anemia is even more common in children than in older IBD patients. Oral iron was given to half of adolescents and adults but, despite similar tolerance and efficacy, only a quarter of children with iron-deficient anemia. Reasons for the apparent underutilization of iron therapy include a perceived lack of benefit and concerns about side effects, including worsening of IBD activity.

The aetiology and impact of malnutrition in paediatric inflammatory bowel disease

Disease-associated undernutrition of all types is very common in paediatric inflammatory bowel disease (IBD). Recent weight loss remains one of the triad of clinical manifestations and a cornerstone for the diagnosis of Crohn's disease (CD), although significantly fewer patients now present as being underweight. Recent evidence suggests that the introduction of medical treatment will quickly restore body weight, although this does not reflect concomitant changes in body composition. CD children present with features of nutritional cachexia with normal fat stores but depleted lean mass. Poor bone health, delayed puberty and growth failure are additional features that further complicate clinical management. Suboptimal nutritional intake is a main determinant of undernutrition, although activation of the immune system and secretion of pro-inflammatory cytokines exert additional independent effects. Biochemically low concentrations of plasma micronutrients are commonly reported in IBD patients, although their interpretation is difficult in the presence of an acute phase response and other indices of body stores adequacy are needed. Anaemia is a common extraintestinal manifestation of the IBD child. Iron-deficient anaemia is the predominant type, with anaemia of chronic disease second. Decreased dietary intake, as a result of decreased appetite and food aversion, is the major cause of undernutrition in paediatric IBD. Altered energy and nutrient requirements, malabsorption and increased gastrointestinal losses are additional factors, although their contribution to undernutrition in paediatric CD needs to be studied further.

Serum prohepcidin levels in children with solid tumors, inflammatory bowel disease and iron deficiency anemia

BACKGROUND

Prohepcidin is one of the regulators of iron metabolism. Few studies examined its relation with solid tumors (ST), inflammatory bowel disease (IBD) and iron deficiency anemia (IDA) in children.

METHODS

We measured serum prohepcidin (SP), soluble transferrin receptor (sTfR), serum ferritin (SF), serum iron (SI), transferrin saturation (TS), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels in ST (n = 16), IBD (n = 15), IDA (n = 14) and controls (n = 18).

RESULTS

The mean SP was significantly higher in ST and IBD than in IDA and controls. SP was significantly correlated with SF in ST, IBD and ESR for IBD and CRP for ST and hemoglobin for ST.

CONCLUSION

Elevated SP may be a clinically important predictor of inflammation and leads to anemia by impairing iron utilization in IBD and ST. SP decreases in IDA and is correlated with TS but not with SF or sTfR.

Nutrition in pediatric inflammatory bowel disease

Nutrition interventions play a central role in the treatment and management of inflammatory bowel disease in children. Malnutrition is a common presenting symptom in both pediatric ulcerative colitis and Crohn's disease and is associated with increased morbidity. Providing macronutrients can improve growth; likewise, identifying and correcting micronutrient deficiencies can improve comorbid conditions like osteopenia and anemia. Although many patients manipulate their diets to help treat their inflammatory bowel disease, only parenteral nutrition with bowel rest and exclusive enteral nutrition therapy have been shown effective for the treatment of inflammatory bowel disease.

Diagnosis and management of iron deficiency anemia in patients with IBD

Anemia is the most prevalent extraintestinal complication of IBD. It can affect quality of life and ability to work, and can also increase the hospitalization rate in patients with IBD. Although the causes of anemia in IBD are multifactorial, iron deficiency anemia (IDA) is the most common. Assessment of the iron status of patients who have a condition associated with inflammation, such as IBD, by using common biochemical values is insufficient. However, new indices of iron metabolism (for instance ferritin:transferrin receptor ratio, reticulocyte hemoglobin content or percentage of hypochromic red blood cells) may help to improve the assessment of iron status in patients with IBD. The treatment of IDA traditionally involves oral iron supplementation. However, because of extensive gastrointestinal adverse effects, and data showing that the use of oral iron in IBD may be associated with disease exacerbation, current guidelines suggest that iron supplementation in IBD should be administered intravenously. This Review provides an overview of iron homeostasis in health before discussing diagnostic and therapeutic strategies for IDA in patients with IBD.

Evaluation of erythrocytes, platelets, and serum iron profile in dogs with chronic enteropathy

The aim of this study is to evaluate iron status, erythrocyte, and platelet modifications in dogs with chronic enteropathy (CE). Dogs were grouped as food-responsive diarrhea (FRD, n = 11), antibiotic-responsive diarrhea (ARD, n = 5), and steroid-responsive diarrhea (SRD, n = 6) relating to therapeutic-response. Clinical and haematological findings, evidence of gastrointestinal blood loss, and iron metabolism were evaluated before and after treatment. A mild normocytic or microcytic anemia and thrombocytosis were identified, respectively in 18.0% and 31.8% of CE dogs. No significant differences between pre- and posttreatment of hematocrit, haemoglobin, and mean corpuscular volume, platelet count and mean platelet volume were found. Statistical analysis pointed out significant differences between pre- and posttreatment in serum iron (P < .03) and unsaturated iron binding capacity (UIBC) (P < .01). No significant correlations were found between these parameters and canine Inflammatory Bowel Disease activity index and pattern of CE as well.

The etiology and treatment outcome of iron deficiency and iron deficiency anemia in children

This study aimed to evaluate the frequency of the diverse causes of iron deficiency (ID) and iron deficiency anemia (IDA) and to investigate the treatment outcomes in children. ID was defined as a serum ferritin level<12 microg/L and a transferrin saturation<10%. IDA was established as ID combined with a low hemoglobin level judged by age and gender-specific reference intervals. A total of 116 ID patients were categorized into 4 groups: group I:<2 years old (n=45), group II: 2 to 10 years old (n=13), group III:>10 years old, male (n=18), and group IV: >10 years old, female (n=40). One hundred of them (86.2%) were diagnosed with IDA. The most common causes of ID were inadequate intake in group I (55.6%) and blood loss in groups II (46.1%) and IV (37.5%). Helicobacter pylori-associated ID mainly occurred in children more than 10 years old. Forty-five of 57 (78.9%) IDA patients who had underlying diseases treatment and/or iron supplementation for 3 months recovered their hemoglobin levels (follow-up range: 6-27 mo). In conclusion, the peak incidences of childhood ID were ages under 2 years old and 10-18 years old. Different age groups and sexes showed characteristic etiologies. The outcomes of childhood ID were good.

Prediction of 6-thioguanine nucleotides levels in Japanese patients with inflammatory bowel diseases during long-term thiopurine administration

BACKGROUND

The monitoring of 6-thioguanine nucleotides (6-TGN) levels is warranted during thiopurine therapy for patients with inflammatory bowel diseases.

AIMS

The aim of this study was to elucidate the parameters that can predict the 6-TGN levels among Japanese patients with inflammatory bowel diseases undergoing thiopurine therapy.

MATERIAL AND METHODS

The 6-TGN levels were measured in 54 patients with inflammatory bowel diseases (32 with ulcerative colitis and 22 with Crohn's disease), who had been administered azathioprine or 6-mercaptopurine for more than 90 days. Possible correlations between the hematologic parameters and 6-TGN levels were investigated. The clinical and hematologic variables were evaluated to determine the 6-TGN levels of less than or over 235 pmol/8 x 10(8) RBCs.

RESULTS

The 6-TGN levels correlated significantly with changes in the mean corpuscular volume (R = 0.423, p = 0.001) and the lymphocyte counts (R = -0.280, p = 0.04). A multivariate analysis revealed changes in the mean corpuscular volume (OR: 1.22, 95% CI: 1.07-1.40) and hemoglobin levels (OR: 0.59, 95% CI: 0.35-0.99) to be factors predictive of the 6-TGN levels. An increase in the mean corpuscular volume of 3.5 fl was determined to be the most preferable cut-off value to distinguish patients with 6-TGN >or= 235 pmol/8 x 10(8) RBCs from those with a lower concentration.

CONCLUSIONS

Changes in the mean corpuscular volume are considered to be predictive of the 6-TGN levels in patients with inflammatory bowel diseases receiving thiopurine therapy.

Evaluation of serum transferrin receptor and sTfR ferritin indices in diagnosing and differentiating iron deficiency anemia from anemia of chronic disease

OBJECTIVE

The present study was conducted to assess the utility of serum transferrin receptor (sTfR) and sTfR ferritin indices to differentiate ACD from IDA and also to diagnose coexisting IDA and ACD.

METHODS

The study group comprised of 30 IDA patients, 30 cases of ACD and 30 age and sex matched controls. Complete hemogram with peripheral smear examination, markers of ACD, iron profile including serum ferritin and serum transferrin receptor levels were done in all patients and controls. Serum TfR and ferritin indices were calculated.

RESULTS

sTfR levels were significantly higher in the IDA group compared to ACD group (p<0.001). ACD group was further subdivided into two groups on the basis of sTfR levels (B1<3 microg/ml and B2 > or = microg/ml), suggesting coexisting IDA in group B2. sTfR/log ferritin index was > 1.5 in all cases of IDA and ACD with coexisting IDA while all pure ACD cases and control subjects had sTfR/log ferritin index < 1.5. All case in IDA group had log sTfR/serum ferritin index > 2.55 and all patients with ACD with or without associated iron deficiency had log sTfR/serum ferritin ratio < 2.55.

CONCLUSION

The sTfR levels along with the above mentioned indices can be very useful in differentiating pure IDA, ACD and ACD with coexisting iron deficiency, thus providing a noninvasive alternative to bone marrow iron.

Anemia and inflammatory bowel diseases

Too often anemia is considered a rare or unimportant manifestation in inflammatory bowel disease (IBD). However, over the last 10 years a number of studies have been conducted and the most relevant conclusions obtained are: (1) anemia is quite common in IBD; (2) although in many cases anemia parallels the clinical activity of the disease, many patients in remission have anemia, and iron, vitamin B12 and/or folic acid deficiency; (3) anemia, and also iron deficiency without anemia, have important consequences in the clinical status and quality of life of the patient; (4) oral iron can lead to gastrointestinal intolerance and failure of treatment; (5) intravenous iron is an effective and safe way to treat iron deficiency; (6) erythropoietin is needed in a significant number of cases to achieve normal hemoglobin levels. Thus, the clinician caring for IBD patients should have a comprehensive knowledge of anemia, and apply recently published guidelines in clinical practice.

Pediatric reference intervals for soluble transferrin receptor and transferrin receptor-ferritin index

BACKGROUND

Recent studies showing an improved diagnosis of iron deficiency (ID) with soluble transferrin receptor (sTfR) and sTfR-ferritin index did not take into account the age-dependency of sTfR and ferritin. Moreover, there is a paucity of data on pediatric reference intervals for sTfR and sTfR-ferritin index.

METHODS

A study cohort of 436 apparently healthy children was analyzed to establish reference intervals for ferritin, transferrin, sTfR and sTfR-ferritin index. To account for age-dependency, standard deviation scores (Z-scores) for these markers were calculated. The association between these parameters and C-reactive protein (CRP) was analyzed.

RESULTS

The Z-scores of ferritin, transferrin and sTfR had a significant association with CRP, whereas the Z-score of sTfR-ferritin did not correlate with CRP. The reference intervals of these parameters were reported.

CONCLUSION

Among the different markers of ID, the Z-scores of sTfR, transferrin and ferritin, but not sTfR-ferritin index, associate with the inflammatory status.

Common misconceptions in the diagnosis and management of anemia in inflammatory bowel disease

Anemia is the most common systemic complication of inflammatory bowel disease (IBD); so common that it is almost invariably not investigated and rarely treated. Several misconceptions are the reason for these clinical errors, and our goal will be to review them. The most common misconceptions are: anemia is uncommon in IBD; iron deficiency is also uncommon; just by treating the intestinal disease, anemia will be corrected; iron deficiency is the only cause for anemia in IBD; ferritin is an accurate parameter for the diagnosis of iron deficiency in IBD; the impact of anemia on the quality of life of IBD patients is limited; iron supplementation is rarely needed in IBD; high-dose oral iron solves the problem of iron malabsorption in IBD; intravenous (IV) iron is dangerous and of no proven benefit in IBD; IV iron is useful only for severe anemia; and erythropoietin has no role in the treatment of IBD anemia. These misconceptions are not evidence-based. On the contrary, there is enough evidence to support the following statements: (a) anemia is very common in IBD, (b) anemia should be investigated with care because many factors can be responsible, (c) treatment of anemia results in clear improvement in the objective parameters of well-being, especially in the quality of life, (d) IV iron is safe and effective in the treatment of iron deficiency anemia in IBD patients, and (e) erythropoietin is useful in a subset of patients with refractory anemia. Anemia diagnosis and treatment must not be neglected in IBD patients, and several misconceptions should be promptly abandoned.

Aluminum is a potential environmental factor for Crohn's disease induction: extended hypothesis

Aluminum (Al) is a common environmental compound with immune-adjuvant activity and granulomatous inflammation inducer. Al exposure in food, additives, air, pharmaceuticals, and water pollution is ubiquitous in Western culture. Crohn's disease (CD) is a chronic relapsing intestinal inflammation in genetically susceptible individuals and is influenced by yet unidentified environmental factors. It is hypothesized, in the present review, that Al is a potential factor for induction or maintaining the inflammation in CD. Epidemiologically, CD incidence is higher in urban areas, where microparticle pollution is prevalent. Al immune activities share many characteristics with the immune pathology of CD: increased antigen presentation and APCs activation, many luminal bacterial or dietary compounds can be adsorbed to the metal and induce Th1 profile activity, promotion of humoral and cellular immune responses, proinflammatory, apoptotic, oxidative activity, and stress-related molecule expression enhancement, affecting intestinal bacterial composition and virulence, granuloma formation, colitis induction in an animal model of CD, and terminal ileum uptake. The Al-bacterial interaction, the microparticles homing the intestine together with the extensive immune activity, put Al as a potential environmental candidate for CD induction and maintenance.

Systematic review: managing anaemia in Crohn's disease

BACKGROUND

Anaemia is a serious complication of Crohn's disease that triggers hospitalization and, if not interfered with, may lead to death.

AIMS

To systematically summarize and compare the literature on anaemia in Crohn's disease.

METHODS

For this systematic review the literature was searched for English-language articles using anaemia, Crohn* and IBD as key words. 144 articles were identified and sorted according to the following topics: prevalence, aetiology, diagnostic tests and therapy.

RESULTS

The reported prevalence of anaemia varied between 6.2% and 73.7%, with higher reported frequencies in older studies and in in-patients. Iron deficiency is the most common underlying condition. Vitamin B12 deficiency is related to the extent of ileal resection but has rarely impact on anaemia. Diagnostic criteria are not established and treatment guidelines are missing. Oral iron supplementation seems effective for short periods but intolerance leads to discontinuation in up to 21%. Eleven of 11 studies show that oral iron enhances intestinal inflammation and colon carcinogenesis in animal models of colitis. Intravenous iron supplementation with iron sucrose has been tested in over 250 Crohn's disease patients, is safe, effective and does not carry such hazards.

CONCLUSIONS

As disease activity is determining the degree of anaemia in Crohn's disease, implementation of more effective therapy for Crohn's disease will lower its incidence. However, further studies regarding the safety and effectiveness of iron supplementation are needed.

High-iron diet: foe or feat in ulcerative colitis and ulcerative colitis-associated carcinogenesis

Anemia associated with long-standing chronic inflammation and iron deficiency, and the increased risk for the development of dysplasia and carcinoma, are two of the most common complications in patients with ulcerative colitis (UC). Because of iron and nutrition deficiency, UC patients are encouraged to consume a high-protein and high-iron diet. The crucial clinical question is the effect of a high-iron diet on inflammation activity and inflammation-driven carcinogenesis. Is a high-iron diet a foe or a feat in UC and UC-associated carcinogenesis? This review updates the progress and information on (1) iron nutrition and iron-deficiency anemia in patients with UC, (2) experimental evidence of the exacerbating effect of a high-iron diet on UC and its associated carcinogenesis and the difference between a high-iron diet and parental iron supplementation, (3) the clinical efficacy of, and concerns about, oral and intravenous iron supplements in patients with inflammatory bowel disease and iron deficiency anemia, and (4) the clinical implications of long-term iron supplements and management of UC. These experimental findings from animal models provide evidence to warrant further consideration and clinical studies of iron nutrition, inflammation activity, and cancer development.

Treatment of iron deficiency anemia in pediatric inflammatory bowel disease

Anemia is a frequent extraintestinal manifestation of inflammatory bowel disease (IBD) that is commonly overlooked, despite its significant impact on quality of life. Characteristic symptoms include chronic fatigue, headache, and subtle impairment of cognitive function, although some less common symptoms include dyspnea, dizziness, pica, angular stomatitis, shortened attention span, and esophageal webs. Several types of anemia are associated with IBD, but iron deficiency anemia (IDA) accounts for the majority of cases and others include anemia of chronic disease, anemia associated with vitamin deficiency (vitamin B12 and folate), autoimmune anemia, and anemia caused by medication used to treat IBD. The diagnosis of IDA relies on laboratory blood tests. Therefore, these tests should be obtained on a regular basis because characteristic symptoms may be absent or not readily recognized by patients and their clinicians. Complete blood count may suffice; however, iron studies and serum vitamin levels may be necessary to differentiate between specific types of anemia. During the diagnostic process, it is important to consider coexistence of different types of anemia, especially if no response to therapy is noted. The therapy for anemia is directed towards treatment of the underlying inflammatory process and supplemental therapy, depending on the type of deficiency. Iron deficiency anemia is treated with iron preparations, first orally, and if unresponsive or if associated with untoward adverse events leading to decrease in adherence with the therapeutic regimen, with intravenous preparations. Intramuscular therapy has been abandoned due to high rate of complications. Intravenous therapy may be administered as a multiple-dose regimen (intravenous iron sucrose and gluconate) or as a single intravenous dose (iron dextran), which is associated with a higher risk of allergic infusion reactions and requires obligatory test dose administration. Treatment with erythropoietin is reserved for a select subgroup of patients with anemia of chronic disease. With appropriate treatment, the majority of patients with IBD will have significant improvement or resolution of anemia, which can lead to a better quality of life. However, a high index of suspicion should be maintained in order to identify the precise cause of anemia and to prescribe the appropriate therapy.

Erythropoietin levels in children and adolescents with inflammatory bowel disease

Iron deficiency anemia (IDA) and anemia of chronic disease (CDA) are often encountered in patients with inflammatory bowel disease (IBD). Inadequate intake or loss of iron is a clear cause of IDA, but mechanisms of CDA induction are multifactorial and involve erythropoiesis disturbance due to circulating inflammation mediators. The authors investigated erythropoietin (Epo) levels in children and adolescents with IBD and correlated them to disease activity, with the aim of gaining an improved understanding of the role of Epo in CDA. Thirty-three patients with IBD were examined (18 boys, 15 girls) ages 4 to 15 years (median 11 years). Two study groups related to the disease activity were formed: group A, those with active disease (n = 21), and group B, those in remission (n = 12). Epo levels were measured using a two-site chemiluminescence immunoassay. Predictive Epo values in response to the degree of anemia were calculated by the equation: logEpo = (3.48 - 0.20) x Hb. According to the results, CDA anemia was present only in patients with active disease. These patients also had a significantly higher possibility of altered Epo levels than expected compared with patients with inactive disease (16/21 vs. 4/12, P < 0.05). It was also interesting that most of the patients with anomalous Epo concentrations presented with an elevated Epo value compared with that expected from the calculation (14/20). It seems that disturbed Epo concentrations are correlated with disease activity in children and adolescents with IBD. It is possible that failure of the bone marrow to respond to increased Epo levels leads to further incremental response. These in turn lead to the high Epo concentrations detected in most of the authors' patients. Impaired Epo production is another mechanism of CDA development and is the one mainly expressed in patients with low Epo values.

Dietary iron affects inflammatory status in a rat model of colitis

Iron deficiency anemia is a common feature in inflammatory bowel disease, and oral supplementation is one of the mainstay therapies. However, there is some concern that oral iron supplementation may lead to oxidative stress and exacerbation of inflammation. Our objective was to study the effect of severely deficient, moderately deficient, normal and high iron status on oxidative stress and the course of inflammation in a rat model of colitis induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS). The rats were randomly assigned to receive the low-iron diet for 3 (moderately iron-deficient group, n = 16) or 5 (severely iron-deficient group, n = 16) wk, the normal iron diet for 2 wk (normal iron group, n = 16) or the high-iron diet for 2 wk (high-iron group, n = 16). Malondialdehyde concentration, electroparamagnetic resonance measurement, myeloperoxidase activity, and histological analysis were used to evaluate oxidative stress. Noncolitic rats in the high-iron group had higher oxidative stress parameters than those in the other groups. The induction of colitis resulted in severe inflammatory changes in the high-iron and severely iron-deficient groups, and produced higher histological scores in the colon of the normal and high-iron groups. Iron overload, oxidative stress, and inflammation were lower in the moderately iron-deficient group compared with the other 3 groups. In conclusion, we suggest that low rather than normal or high iron supplementation should be considered for the treatment of iron deficiency in inflammatory bowel disease.

Prevalence and outcomes of anemia in inflammatory bowel disease: a systematic review of the literature

The prevalence of anemia in patients with inflammatory bowel disease ranges from 8.8% to 73.7% depending on the patient subpopulation. Anemia, one of many extraintestinal complications of ulcerative colitis and Crohn disease, is generally defined as a hemoglobin value <120 g/L or hematocrit <0.4; severe anemia is defined as a hemoglobin level <100 g/L. Many patients have been shown to be intolerant of oral iron replacement therapy or their anemia was refractory to such supplementation. Correction of anemia through the administration of intravenous iron saccharate and/or supplemental erythropoietin has been shown to improve patient hematologic indices and quality of life. Future studies are needed to determine the type of patients at highest risk of developing severe anemia as well as the treatment interventions with the most beneficial effect.

Soluble transferrin receptor in Aboriginal children with a high prevalence of iron deficiency and infection

OBJECTIVES

Aboriginal children in tropical Australia have a high prevalence of both iron deficiency and acute infections, making it difficult to differentiate their relative contributions to anaemia. The aims of this study were to compare soluble transferrin receptor with ferritin in iron deficiency anaemia (IDA), and to examine how best to distinguish the effect of iron deficiency from infection on anaemia.

METHODS

We conducted a prospective study of 228 admissions to Royal Darwin Hospital in children from 6 to 60 months of age. Transferrin receptor concentrations were measured by a particle-enhanced immunoturbidimetric assay and ferritin by a microparticle enzyme immunoassay.

RESULTS

On multiple regression, the best explanatory variables for haemoglobin differences (r2=33.7%, P<0.001) were mean corpuscular volume (MCV), red cell distribution width (RDW) and C-reactive protein (CRP); whereas transferrin receptor and ferritin were not significant (P>0.4). Using > or =2 abnormal indices (MCV, RDW, blood film)+haemoglobin <110 g/l as the reference standard for IDA, transferrin receptor produced a higher area under the curve on receiver operating characteristic curve analysis than ferritin (0.79 vs. 0.64, P<0.001) or the transferrin receptor-ferritin index (0.77). On logistic regression, the effect of acute infection (CRP) on haemoglobin was significant (P<0.001) at cut-offs of 105 and 110 g/l, but not at 100 g/l when only iron deficiency indicators (MCV, RDW, blood film) were significant.

CONCLUSIONS

Transferrin receptor does not significantly improve the diagnosis of anaemia (iron deficiency vs. infection) over full blood count and CRP, but in settings with a high burden of infectious diseases and iron deficiency, it is a more reliable adjunctive measure of iron status than ferritin.

Soluble transferrin receptor for the evaluation of erythropoiesis and iron status

Iron transport in the plasma is carried out by transferrin, which donates iron to cells through its interaction with a specific membrane receptor, the transferrin receptor (TfR). A soluble form of the TfR (sTfR) has been identified in animal and human serum. Soluble TfR is a truncated monomer of tissue receptor, lacking its first 100 amino acids, which circulates in the form of a complex of transferrin and its receptor. The erythroblasts rather than reticulocytes are the main source of serum sTfR. Serum sTfR levels average 5.0+/-1.0 mg/l in normal subjects but the various commercial assays give disparate values because of the lack of an international standard. The most important determinant of sTfR levels appears to be marrow erythropoietic activity which can cause variations up to 8 times below and up to 20 times above average normal values. Soluble TfR levels are decreased in situations characterized by diminished erythropoietic activity, and are increased when erythropoiesis is stimulated by hemolysis or ineffective erythropoiesis. Measurements of sTfR are very helpful to investigate the pathophysiology of anemia, quantitatively evaluating the absolute rate of erythropoiesis and the adequacy of marrow proliferative capacity for any given degree of anemia, and to monitor the erythropoietic response to various forms of therapy, in particular allowing to predict response early when changes in hemoglobin are not yet apparent. Iron status also influences sTfR levels, which are considerably elevated in iron deficiency anemia but remain normal in the anemia of inflammation, and thus may be of considerable help in the differential diagnosis of microcytic anemia. This is particularly useful to identify concomitant iron deficiency in a patient with inflammation because ferritin values are then generally normal. Elevated sTfR levels are also the characteristic feature of functional iron deficiency, a situation defined by tissue iron deficiency despite adequate iron stores. The sTfR/ferritin ratio can thus describe iron availability over a wide range of iron stores. With the exception of chronic lymphocytic leukemia (CLL) and high-grade non-Hodgkin's lymphoma and possibly hepatocellular carcinoma, sTfR levels are not increased in patients with malignancies. We conclude that soluble TfR represents a valuable quantitative assay of marrow erythropoietic activity as well as a marker of tissue iron deficiency.