Takao Matsuura

New Platelet Antigen, Siba, Involved in Platelet Transfusion Refractoriness in a Japanese Man

Abstract. Siba, a new platelet‐specific alloantigen involved in a case of platelet transfusion refractoriness is reported. The IgG platelet alloantibody was detected in a multiply transfused patient of Japanese extraction (Sib), by the presence of HLA antibodies. After transfusion of HLA‐compatible platelets, the patient suffered from refractoriness. Adsorption studies with pooled lymphocytes showed that the serum contained anti‐platelet activity. Family studies indicate that Siba is inherited as an autosomal codominant trait and separate from HLA and Baka. As of this report, segregation from Zw (PlA) and Yuk (Pen) antigen systems have not yet been determined. The gene frequency of Siba in the Japanese population is estimated to be 0.136.

Electrocardiographic changes occurring in long-term plasmaphereses in older donors.

Over the past six years at Fukuchiyama Red Cross Blood Center electrocardiographic (ECG) changes were studied in 314 older (over 50-years old) apheresis donors. ECG was examined prior to the first plasmapheresis experience and was compared with ECG recorded at 4 month intervals thereafter. The aim of this study was to ascertain whether plasmaphereses, as it is currently performed, exposes long-term donors to harmful effects. After long-term plasmaphreses, the following findings without clinical symptoms, were observed: slight prolongations of PQ or QT time in 12 cases; left axis deviation in 3 cases; slight left ventricular highvoltage in 3 cases; slight low QRS wave length in 5 cases; and premature ventricular contraction in 2 cases. These findings were in the normal range and were observed mainly in older persons. Comparison of ECGs recorded prior to first plasmapheresis and those observed thereafter showed almost no significant difference. Based upon this 6-year study, we conclude that donors are not at risk of ECG change due to plasmaphereses.