Reduced soluble transferrin receptor concentrations in acute malaria in Vanuatu.

Abstract

Abstract. Soluble transferrin receptor (sTfR) concentration is a sensitive index of iron deficiency when used in conjunction with ferritin measurements in adults. One advantage of this assay is that unlike ferritin it does not appear to be affected by a range of infectious and inflammatory conditions or by pregnancy, rendering it a promising adjunct to the diagnosis of iron deficiency in tropical populations. We have measured plasma sTfR concentrations in a group of malaria patients (n ϭ 21) and asymptomatic (18) and aparasitemic (76) controls in Vanuatu. Plasma sTfR concentration was significantly reduced in individuals with acute malaria (P ϭ 0.003). While this observation provides evidence that erythropoeitic suppression may be an important etiologic component in malarial anemia, it also suggests that malaria may be a confounding factor when interpreting sTfR concentrations in such populations. The role of sTfR in the diagnosis of iron deficiency in tropical populations remains to be established.The diagnosis of iron deficiency can be difficult in tropical communities. Routine tests can be unreliable; for example, microcytosis is a poor indicator in populations where hemoglobinopathies are common 1,2 and acute malaria can result in both anemia 3 and elevated serum ferritin concentrations. 4,5 The transmembrane iron transport protein transferrin receptor (CD71) is a dimeric protein consisting of two identical 95-kD subunits. During red blood cell maturation, membrane transferrin receptor is degraded by endosomal digestion and an 85-kD fragment, soluble transferrin receptor (sTfR), is released into the circulation. 6 Plasma levels can be measured using a sensitive ELISA method. It has been estimated that 80% of circulating sTfR originates from developing red blood cells. The STfR concentration is pathologically increased in the presence of tissue iron deficiency, 7,8 and has been shown to be a sensitive index of this condition when interpreted in conjunction with ferritin measurements in adults. 7,8 Unlike ferritin, sTfR is not affected by a range of infections, inflammatory conditions or by pregnancy 9,10 and might thus be a useful tool in the assessment of iron status in tropical populations. We have investigated this possibility by measuring both sTfR and ferritin concentrations in malaria patients and control subjects living in Vanuatu.

Assessment of Regression Models for Adjustment of Iron Status Biomarkers for Inflammation in Children with Moderate Acute Malnutrition in Burkina Faso

“…However, as previously mentioned in contrast to our results others have observed positive 322 relationships between inflammation markers and sTfR (10)(11)(12)(13)(14) or shown that that sTfR 323 decreased in malaria (8). In addition to increased erythropoiesis, higher sTFR concentrations 324 in children with infections may also be due to poorer iron status.…”

The influence of vitamin A status on iron-deficiency anaemia in anaemic adolescent schoolgirls in Myanmar

“…However the low prevalence of SCI meant that inflammation had little impact on nutritional biomarkers in the present study ( Table 2). The results also suggest that sTfR concentrations were not affected by SCI although other workers have reported different results (40)(41)(42) . The prevalence of SCI will depend on the intensity of infections and the age of the individuals.…”

Influence of inflammation as measured by α-1-acid glycoprotein on iron status indicators among HIV-positive postpartum Zimbabwean women

“…Higher TfR concentrations among people infected with malaria (Mockenhaupt et al, 1999;Stoltzfus et al, 2000;Menendez et al, 2001;Verhoef et al, 2001) have led investigators to suggest that the high TfR reflects increased erythropoeisis resulting from malaria induced hemolysis. Others, however, have reported lower TfR concentrations during malaria suggestive of blunted erythropoeisis (Williams et al, 1999;Beesley et al, 2000).…”