Background:Severe malnutrition is associated with septic infections. The concentrations of fibronectin, albumin, and transferrin in plasma were measured in three groups of children with protein-energy malnutrition, aged 1-3 years, each group comprising 20 children. The aim of which was to test whether plasma fibronectin, being an opsonic protein, was reduced in such children, and if it was a useful index for assessing the severity of malnutrition.Methods:The concentrations of fibronectin, albumin, and transferrin in plasma were studied by enzyme immunoassay/immunoblotting, spectrophotometry and immunoturbidimetry respectively.Results:All values were significantly lower in the patients with malnutrition than in the age- and sex-matched well-nourished Nigerian reference children. Within the malnourished group, the fibronectin value was evenly reduced in all subgroups. Albumin and transferrin values were lowest in the patients with kwashiorkor, highest in the marasmic patients, and intermediate in the patients with marasmic kwashiorkor; the values correlated mutually in individual cases as well, but not with the fibronectin levels. Neither plasma fibronectin fragmentation nor tissue fibronectin was detected in any patient with malnutrition or in the reference subjects.Conclusions:The reduced plasma fibronectin values in these patients may be due to reduced synthesis by the liver, as evidenced by the equally reduced albumin and transferrin concentrations and/or to the multiple infections characteristic of the patients.