BACKGROUND Published studies on the serum immunoglobulin concentrations of patients with protein-energy malnutrition (PEM) have been contradictory. This report describes such a study in 21 Senegalese children. METHODS Twenty one Senegalese infants (mean age: 19 +/- 2 months) with severe PEM were included in the study. Their weight was less than 32% of the normal range-for-height and all had sparse, thin hair and dyspigmentation of the skin. They were all suffering from hypoproteinemia (less than 70% of normal) and hypoalbuminemia (less that 61% of normal). The presence or absence of edema, loss of subcutaneous fat and mental changes were used to classify them into three groups. 1) kwashiorkor: eight infants; 2) marasmus: eight infants; 3) kwashiorkor plus marasmus: five infants. The control group comprised 27 infants living in the same area and having the same dietary habits as the 21 sick infants. The 21 infants with malnutrition were refed for 3 weeks with a diet supplying 100-150 Kcal/kg/d and 5-8 g/kg/d protein. The plasma concentration of proteins, prealbumin and immunoglobulins was measured on days 0, 8, 15 and 21. RESULTS The only significant change was in the IgG concentrations of group 1, which increased to normal levels by day 15 as did the total protein and prealbumin. CONCLUSIONS Severe PEM can lead to a loss of one class of immunoglobulins, but this can be restored by refeeding.