title: Serum transferrin receptor levels are increased in asymptomatic and mild Plasmodium falciparum-infection.
abstract: OBJECTIVE
  The serum transferrin receptor (sTfR) concentration in an individual reflects the extent of erythropoietic activity and is considered a useful marker of iron deficiency independent of concurrent inflammation or infection. However, data on the impact of malaria on this parameter are ambiguous. We have examined potential associations of asymptomatic and mild Plasmodium falciparum-infections and of several erythrocyte variants with sTfR values in South West Nigeria.
  
  
  METHODS
  In a cross-sectional study among 161 non-hospitalized children, sTfR concentrations and P. falciparum parasitemia were assessed. In addition, hemoglobin (Hb) and serum ferritin values, Hb-types, glucose-6-phosphate dehydrogenase (G6PD)deficiency and a-globin genotypes were determined and the effects of these factors on sTfR levels were analyzed by univariate and multivariate statistical methods.
  
  
  RESULTS
  P. falciparum-infection was present in 77% of the children. Mean sTfR levels were higher in infected than in non-infected children (geometric mean, 3.68, 95% confidence interval [3.5-3.9] vs. 2.99 [2.7-3.3] mg/L; p = 0.0009). There was a significant trend for higher sTfR values with increasing parasite density. sTfR values decreased continuously with age. Hb-types, G6PD-, and a-globin genotypes did not correlate with sTfR levels. In the multivariate analysis, age, Hb and log ferritin values, and parasite density of P. falciparum were independently associated with log sTfR values.
  
  
  CONCLUSIONS
  sTfR concentrations are increased in asymptomatic and mild P. falciparum-infections suggesting adequate bone marrow response in this condition. The diagnostic value of sTfR levels for iron deficiency may be impaired in areas where stable malaria occurs.
authors.affiliation: Institut für Tropenmedizin, Spandauer Damm 130, 14050 Berlin, Germany. frank.mockenhaupt@charite.de
authors.forename: F P
authors.initials: FP
authors.lastname: Mockenhaupt
authors.forename: J
authors.initials: J
authors.lastname: May
authors.forename: K
authors.initials: K
authors.lastname: Stark
authors.forename: A G
authors.initials: AG
authors.lastname: Falusi
authors.forename: C G
authors.initials: CG
authors.lastname: Meyer
authors.forename: U
authors.initials: U
authors.lastname: Bienzle
mesh_terms: D000367:Age Factors; D000818:Animals; D002648:Child; D002675:Child, Preschool; D005260:Female; D005293:Ferritins / Q000097:blood; D005955:Glucosephosphate Dehydrogenase Deficiency / Q000469:parasitology; D006444:Hemoglobin C; D006451:Hemoglobin, Sickle; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016778:Malaria, Falciparum / Q000097:blood* / Q000453:epidemiology / Q000473:pathology; D008297:Male; D015999:Multivariate Analysis; D009549:Nigeria / Q000453:epidemiology; D011990:Receptors, Transferrin / Q000097:blood*; D017085:alpha-Thalassemia / Q000469:parasitology
chemical_list: D006451:Hemoglobin, Sickle; D011990:Receptors, Transferrin; D005293:Ferritins; D006444:Hemoglobin C