Antibody protein levels in maternal sera in Rh haemolytic disease.

constituent of foetal serum, but it virtually disappears from the circulation very soon after birth and is not detectable in normal adults. The only conditions where cx1FP has been found in the sera of adult humans in significant quantities are primary hepatocellular cancer of the liver and teratocarcinomas. It has been shown that the demonstration of x1FP in the serum of adult patients can be regarded as a reliable indicator of the presence of primary carcinoma of the liver. Synthesis of ct,FP by liver cancer cells is believed to result from derepression of genes which had been, in turn, activated and then repressed during ontogenesis. Techniques most commonly used for the detection of a,FP are bidimensional immuinodiffusion (Ouchterlony), counter-current electro-phoresis, followed by complement-fixa-tion tests, haemagglutinin inhibition and more recently radioimmunoassay and latex agglutination. The relative merits of these techniques, as well as the problems of quantitation, standards, and availability of suitable antisera, will be discussed. The importance of good quality specific high titre antisera is emphasized. The interpretation of results and main sources of error will be considered, including the occurrence of a1FP in conditions other than hepa-toma. Statistical and epidemiological data available to date regarding results obtained in various centres will be presented, as well as our own findings. An automated haemagglutination technique was used to estimate antibody protein levels, in the maternal scra, in 600 pregnancies complicated by Rh incompatibility. Good correlation was found between the maternal antibody protein level and the subsequent severity of haemolytic disease in the baby. The method was found to be very reliable for selecting cases for amniocentesis. In 325 pregnancies (group I) where the mother developed Rh antibodies for the first time, amniocentesis was indicated if the antibody protein value reached or exceeded 15 yg/ml before the end of 34 weeks' gestation. In 275 pregnancies (group II) where the mother had had a previously affected baby, amniocentesis was indicated if the antibody protein level reached 1 0