ABSTRACT
Employment of isoelectrofocussing techniques for the determination of proteinase alpha 1-inhibitor (p alpha 1i) phenotypes helped detect original rare phenotypes. Their accurate identification should be performed with a set of standard sera. The findings of studies on the number of p alpha 1i by Mancini's immunoprecipitation test are analyzed, as are the data of phenotype studies by p alpha 1i isoelectrofocussing in children suffering from acute leukemia and sepsis. The findings evidence a drastic increase of p alpha 1i number, parallelled by the emergence of a manifest anode fraction of a common Pi MM phenotype; this may be regarded as a manifestation of a rare Pi MM anode phenotype in phenotyping. The possible reasons of this phenomenon are discussed; the authors emphasize the significance of analyzing rare p alpha 1i phenotypical variants with standard sera.