SECRETORY ANTI-GIARDIA LAMBLIA ANTIBODIES IN HUMAN-MILK - PROTECTIVE EFFECT AGAINST DIARRHEA

Objective. To determine whether anti-Giardia lamblia secretory IgA (sI gA) antibodies in human milk protect infants from acquisition of or sy mptoms associated with Giardia infection. Methods. One hundred ninety- seven Mexican mother/ infant pairs were followed weekly from birth for diarrheal disease and feeding status. Infant stool specimens were col lected weekly and were cultured for bacterial pathogens and tested for Giardia and rotavirus by enzyme-linked immunosorbent assay. Maternal milk samples were collected weekly for 1 month postpartum and monthly thereafter. To determine the protective effect of anti-Giardia sIgA in milk against infection and against diarrhea due to Giardia, milk samp les from mothers of infected infants and appropriately matched control s were assayed for anti-Giardia sIgA by enzyme-linked immunosorbent as say. Results. Asymptomatic, infected infants ingested significantly (P =.046) higher amounts of milk anti-Giardia sIgA compared with symptom atic, infected infants. However, milk anti-Giardia sIgA concentrations did not differ between Giardia-infected and noninfected infants. Conc lusion. The amount of anti-Giardia sIgA in human milk was associated w ith prevention of symptoms of diarrhea due to Giardia, but not with ac quisition of the organism.