ENZYME-LINKED IMMUNOSORBENT ASSAY FOR IgA ANTIBODIES TO TRYPANOSOMA CRUZI IN CONGENITAL INFECTION

Abstract. With the aim of achieving earlier diagnosis of congenital Trypanosoma cruzi infection, we assessed the usefulness of detecting specific IgA antibody by an ELISA. We evaluated 12 pregnant women chronically infected with T. cruzi, their newborn infants, and three additional neonates with parasitemia at birth. The IgA-specific antibody was detected by adapting the procedure for use of a commercial IgG ELISA, the Hemagent Chagas ’ Kit (Hemagen Diagnostics, Inc., Waltham, MA). Trypanosoma cruzi–specific IgA was detected in 10 (83%) of 12 mothers at deliv-ery, in one of three parasitemic infants, and one of 12 newborns of the chronically infected women. Testing of 13 infants at six months of age revealed IgA in seven infants (54%), of whom four also had persistent T. cruzi-specific IgG. Detection of T. cruzi-specific IgA could provide a criterion for diagnosis of congenital infection in the absence of detectable parasitemia. American trypanosomiasis, or Chagas ’ disease, is caused by the protozoan parasite Trypanosoma cruzi. The disease is endemic in many parts of South and Central America. Se-rologic surveys indicate that 17–18 million individuals in Latin America are infected.1 As many as 30 % of these will develop over time irreversible cardiac and hollow viscera