Development and persistence of antibodies to Entamoeba histolytica in patients with amebic liver abscess. Analysis of 216 cases.

The antibody patterns--obtained by enzyme immunoassay (EIA), complement fixation (CF), indirect hemagglutination (IHA), and latex agglutination (LA)--of 216 patients with amebic liver abscess (ALA) were related to the time of onset of illness and to epidemiological data. The usual period between the stay in an Entamoeba histolytica-endemic area and clinical manifestation of the disease was 8-20 weeks. Increasing antibody concentration affected the sensitivity rates for CF and LA in the first 3 weeks of clinical ALA. In comparison with CF, IHA, and LA, EIA was the most sensitive test, showed the most substantial changes in antibody concentration according to the stage of disease, and measured persisting antibodies for the longest period. Neither the duration of previous stay in tropical countries nor the time when specific chemotherapy was started influenced development or persistence of antibodies in ALA patients. ALA occurred with similar frequency regardless of whether the patient was a long-term resident of the tropics or a short-term visitor to an E. histolytica-endemic area.