Immunological Method for the Detection of the Carrier of Haemophilia B.

Both the immunoassay and bioassay were performed on factor IX activity of haemophilia B patient. Their values were compared with each other. The immunoassay by neutralization was performed as follows: antibody to factor IX was obtained by immunization of purified factor IX to rabbit which was isolated by the technique of DEAE-Sephadex column chromatography using eluate from BaS04 which absorbed factor IX of normal human plasma. In approximately 90% of the cases of definite carriers of haemophilia B, the activity of factor IX by bioassay was observed to be lower than that of factor VIII of haemophilia A carrier. The factor IX activity was observed to be at the same level as factor IX antigen by immunoassay in almost all of the cases, but in the cases of the mother of haemophilia B, and the North Carolina type of haemophilia B the factor IX antigen was much greater than that of activity by bioassay. The same results were obtained by the above mentioned methods using inhibitor substance arising from severe haemophilia B patient. It was suggested that the immunoassay method is useful in detecting the carrier of haemophilia B and North Carolina type of haemophilia B.