Circulating E. histolytica antigens clear with successful treatment of amoebic liver abscess.

An antigen capture ELISA was used to measure serum E. histolytica antigen and antibody levels in 23 patients with amebic liver abscess (ALA), 15 patients with intestinal amebic infections (IAI), and 20 normal controls. 16 of the 23 (70%) with ALA had antigenemia. None of those with IAI or the normal controls had E. histolytica antigen titers of greater than 1:4. All 23 of the patients with ALA had positive antibody titers. Three (20%) with IAI and none of the normal controls had E. histolytica antibody titers greater than 1:100. Antigenemia cleared in all but one of the 23 patients within two months of initiating successful chemotherapy. Antibody titers were much slower to diminish. Measuring E. histolytica antigens in the sera of patients with ALA by increasing the diagnostic specificity may have some diagnostic advantage over measuring only the antibody levels. In addition, serial measurements of antigenemia are useful in monitoring result following chemotherapy.