Conventional and novel peripheral blood iron markers compared against bone marrow in Malawian children.

AIM: Iron deficiency is an important child health problem. Its diagnosis in areas of high infection exposure remains complicated as inflammation may interfere with the accuracy of peripheral iron markers. With this study, we aimed to validate the conventional iron markers and two novel iron markers, hepcidin and Red blood cell Size Factor (RSf), against the reference standard of iron status, bone marrow iron, in children living in an infectious setting. METHODS: We compared ferritin, soluble transferrin receptor, Soluble Transferrin Log-Ferritin Index (sTfR-F), mean cellular volume, mean cellular haemoglobin concentration, hepcidin and RSf, against bone marrow iron in 87 healthy Malawian children (6-66 months) scheduled for elective surgery. RESULTS: Of all children, 44.8% had depleted bone marrow iron stores. Using optimised cut-offs, ferritin (<18 µg/L) and sTfR-F (>1.85) best predicted depleted iron stores with a sensitivity/specificity of 73.7%/77.1% and 72.5%/75.0%, respectively. Hepcidin (<1.4 nmol/L) was a moderate sensitive marker (73.0%) although specificity was 54.2%; RSf poorly predicted depleted iron stores. CONCLUSIONS: We provide the first bone marrow-validated data on peripheral iron markers in African children, and showed ferritin and sTfR-F best predicted iron status. Using appropriately defined cut-offs, these indicators can be applied in surveillance and research. As their accuracy is limited for clinical purposes, more reliable iron biomarkers are still required in African children.

Erythropoiesis in HIV-infected and uninfected Malawian children with severe anemia.

Anemia is common in HIV infection, but the pathophysiology is poorly understood. Bone marrow analysis in 329 severely anemic (hemoglobin <5 g/dl) Malawian children with (n = 40) and without (n = 289) HIV infection showed that HIV-infected children had fewer CD34(+) hematopoietic progenitors (median 10 vs. 15‰, P = 0.04) and erythroid progenitors (2.2 vs. 3.4‰, P = 0.05), but there were no differences in erythrocyte viability and maturation in later stages of erythropoiesis. Despite an HIV-associated reduction in early red cell precursors, subsequent erythropoiesis appears to proceed similarly in HIV-infected and HIV-uninfected children with severe anemia.