The blood donation and transfusion system has contributed significantly to the human health and welfare. However, there still exit emergency situations where blood transfusion is not available. To complement the blood transfusion system, we have developed artificial red cells (hemoglobin vesicles, Hb-V) with the intention of their clinical use. Hemoglobin is purified from expired NAT-inspected RBCs via virus inactivation and removal procedures and regenerated as storable artificial red cells. We established a basis for production processes and clarified the safety and efficacy of Hb-V as a transfusion alternative through preclinical studies with the help of grants from MHLW and AMED. On the other hand, new potential applications of Hb-V are being clarified by taking the advantages of its unique physicochemical properties.
Neonatal alloimmune thrombocytopenia (NAIT) is caused by the formation of maternal alloantibodies against fetal platelet antigens. Multiple anti- human platelet antigen (HPA) alloantibodies have occasionally been detected in maternal sera. In this case report, we present the first Japanese NAIT case with three different anti-HPA antibodies. The proband (second sibling) showed mild thrombocytopenia (73 × 103/μl) without any bleeding tendency at birth. Human leukocyte antigen (HLA) antibodies were negative. A screening assay employing the mixed-passive hemagglutination (MPHA) method suggested the presence of multiple anti-HPA antibodies including anti-HPA-5a antibodies. A monoclonal antibody-specific immobilization of platelet antigens (MAIPA) assay demonstrated a reaction between maternal antibodies and paternal platelets and suggested the presence of alloantibodies against HPA-4, HPA-5, HPA-6, and HPA-15. We also determined the maternal, paternal, and proband's HPA genotype. Furthermore, a MAIPA assay using K562 cells expressing each HPA confirmed the presence of three different alloantibodies, HPA-4b, HPA-5a, and HPA-15b antibodies, in maternal serum. This case strongly suggests that the combined use of MPHA and MAIPA assays may be powerful for detecting and identifying multiple alloantibodies.
We report a case of hemolytic disease of the fetus and newborn (HDFN) caused by anti-D with delayed appearance of RhD (+) red blood cells. The mother was gravid 1, para 1, and A-type RhD (-) and showed an anti-D titer of 1 : 128. The anti-D titer increased to 1 : 256 at 28 weeks of pregnancy. Intrauterine fetal transfusions were performed twice, at 31 and 33 weeks of pregnancy, after diagnosis of fetal anemia. Transfusion volumes were 100 ml and 130 ml, respectively. The newborn was delivered at 36 weeks by labor induction, at which time hemolysis and jaundice were mild and intravenous immunoglobulin (1.5 g/kg) was administered. The blood type of the newborn before intrauterine fetal transfusion was AB-type RhD (+); however, the blood typing test at birth showed O-type RhD (-) and the anti-D antibody titer was 1 : 1,024. This indicated that red blood cells derived from the newborn had disappeared and were completely replaced by the red blood cells from the blood products. Red blood cells derived from the newborn were detected for the first time on day 83 after birth when the anti-D antibody titer had decreased to 1 : 4. We speculate that delayed appearance of the newborn's red blood cells was due to the presence of anti-D. Blood typing before transfusion and serial monitoring of antibody titers should be performed when fetal blood transfusion is needed in a newborn with HDFN.