Amoebic antigen in immunodiagnosis and prognosis of amoebic liver abscess.

The detection of amoebic antigen by counterimmunoelectrophoresis is very useful and important in the immunodiagnosis of invasive hepatic amoebiasis. The antigen was demonstrated in 115 (92%) of 125 patients with amoebic liver abscess. All the 19 cases which showed Entamoeba histolytica in the 'pus' were positive for the antigen and 96 of 106 samples negative for the parasite by smear and culture were also positive for the antigen. In none of the controls was a falsepositive reaction obtained. 12 of 13 liver biopsy specimens were also positive for antigen. The persistence or disappearance of the antigen from the liver pus biopsy specimens was investigated: the antigen disappeared in eight of the 33 cases followed for intervals up to 60 days after cure, suggesting that this is also an important additional criterion for evaluating the prognosis of the disease. Further, it has been shown that amoebic infection is followed by the appearance of specific antigen or antigenic substances in the serum which were demonstrated in 23 of 89 proved cases of amoebic liver abscess cases. Its possible role in immune complex formation and the pathogenesis of the disease is discussed.