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Monoclonal antibody OKM5 and platelet alloantibody anti-Nak have the same specificity.

1990; Japan Academy; Volume: 66; Issue: 2 Linguagem: Inglês

10.2183/pjab.66.41

1349-2896

Yoichi Shibata, Nobuko Kim, Shôji Morita, Ayako Ishijima, Shotaro OKAZAKI,

Heparin-Induced Thrombocytopenia and Thrombosis

The development of alloantibodies to platelet antigens following blood transfusion or during pregnancy causes hemorrhagic disorders including platelet transfusion refractoriness, post-transfusion purpura (PTP) and neonatal alloimmune thrombocytopenia (NAITP).To date, five platelet alloantigen systems have been described.These are Zwa (P1A1)/Zwb (P1A2), Koa (Siba'))/Kob, Baka/Bakb, Yuka/Yukb (Pen), and Bra/Brb.Both Zw and Yuk (Pen) are located on platelet glycoprotein (GP) IIIa; Ko is located on GPIb/IX,2) Bak on GPIIb, and Br on GPIa/IIa.A new platelet alloantigen, Naka, has recently been reported to be involved in a case of platelet transfusion refractoriness.3)The phenotype frequency of Naka has been estimated as 89.6U ~ in the Japanese population.')Here we report that marine monoclonal antibody OKM5 and anti-Naka have the same specificity, indicating that OKM5 is, indeed, a monoclonal alloantibody to Naka.Materials and method.Antisera : Anti-Naka serum (Nakamura) was kindly supplied by Dr. H. Ikeda (Hokkaido Red Cross Blood Center).OKM5, a murine monoclonal antibody, was purchased from Ortho Diagnostic System Inc.This antibody reacts with GPIV (a88kD cell surface antigen expressed by platelets and monocytes) and belongs to the IgG1 subclass.4),5)Platelets: Platelets from 1111 blood donors were supplied by the Saitama Red Cross Blood Center.For the detection of platelet antibodies, the MPHA (mixed passive haemagglutination) test was used.6),7)Results and discussion.We tested several kinds of anti-platelet GP murine monoclonal antibodies on our platelet panel (8 selected persons).The reaction patterns showed that monoclonal antibody OKM5 and anti-Naka have similar specificities : No. 3 was negative, while the other 7 persons were positive (Fig. 1).We therefore tested OKM5 antibody and anti-Naka serum against platelets from 111 healthy blood donors.The typing results obtained with those sera were identical (Table I).Thus we conclude that OKM5 is an alloantibody against GPIV (anti-Naka).There are no data on the frequency of Naka in the Caucasoid population.We suppose that the frequency may be relatively high, as it is in the Japanese population