Soluble transferrin receptor as an indicator of iron deficiency in HIV-infected infants

Background: Iron deficiency is common in human immunodeficiency virus (HIV)-infected infants in sub-Saharan Africa. It is not known whether soluble transferrin receptor (sTfR) is a good indicator of iron deficiency in infants with HIV. Methods: We evaluated sTfR as an indicator of iron deficiency in 134 HIV-infected 9-month-old infants in Kampala, Uganda. Ferritin <12 μg/L and microcytic, hypochromic anaemia were used as indicators of iron deficiency, respectively. The presence of inflammation was indicated by C-reactive protein >5 mg/L or α₁-acid glycoprotein >1 g/L. Results: Receiver operator characteristic curves showed that the area under the curve was 0.67 when sTfR receptor was compared with low ferritin and 0.71 when sTfR was compared with microcyric, hypochromic anaemia. The appropriate calculated cut-offs of sTfR >3.74 μg/mL (43.98 nmol/L) and >3.53 μg/mL (41.55 nmol/L) show adequate specificities of 60% and sensitivities of 63% and 69% for low ferritin and microcytic, hypochromic anaemia, respectively. C-reactive protein and α₁-acid glycoprotein were strongly correlated with serum ferritin (r=0.371 and r=0.458, respectively, both p<0.0001) but were not correlated with sTfR (r=0.009 and r=-0.003, respectively, both p=0.9). In all, 78.6% of infants had α₁-acid glycoprotein >1 g/L and 54.7% had C-reactive protein >5 g/L. Conclusions: Soluble TfR appears to be an adequate indicator of iron deficiency in HIV-infected infants.