title: Expression levels of ABCG2 on cord red blood cells and study of fetal anemia associated with anti-Jr(a).
abstract: The Jr(a) antigen of JR blood group systems is located on ABCG2 and Jr(a-) subjects whose red blood cells (RBCs) lack ABCG2 have been identified mostly among the Japanese. Although anti-Jr(a) can cause fetal anemia, little is known regarding its mechanism.
  
  
  
  We reviewed clinical courses of all reported cases with fetal anemia due to anti-Jr(a) . We analyzed the ABCG2 expressions of cord RBCs at various gestational ages. We examined the effects of sera containing anti-Jr(a) from three pregnancies with fetal anemia or monoclonal anti-Jr(a) on erythropoiesis and phagocytosis. We also examined epitopes of anti-Jr(a) .
  
  
  
  Case series suggested that the majority of fetal anemia with anti-Jr(a) may not be progressive in the later gestational ages. ABCG2 expression levels of cord RBCs were significantly higher than those of adults and neonates with high individual variation and gradually decreased with advancing gestational ages. Anti-Jr(a) did not significantly impact erythroid colony formation, although we detected a tendency toward the suppression of erythroid burst-forming unit formation by anti-Jr(a) using feline marrow cells. Anti-Jr(a) did not induce phagocytosis of sensitized RBCs by monocytes. While many anti-Jr(a) recognized the same regions as a monoclonal anti-ABCG2, 5D3, epitopes of anti-Jr(a) did not correlate with the incidence of fetal anemia.
  
  
  
  ABCG2 expression levels in cord RBCs are higher than those of adults, and the change of ABCG2 expression in erythroid lineage cells may influence the clinical course of fetal anemia with anti-Jr(a) , although we could not detect significant effects of anti-Jr(a) on erythroid colony formation or phagocytosis.
authors: Department of Obstetrics and Gynecology.
authors: Satoko
authors: S
authors: Fujita
authors: Department of Hematology and Oncology.
authors: Hirokazu
authors: H
authors: Kashiwagi
authors: Department of Obstetrics and Gynecology.
authors: Takuji
authors: T
authors: Tomimatsu
authors: Tohoku Block Blood Center, Japanese Red Cross, Miyagi.
authors: Shoichi
authors: S
authors: Ito
authors: Department of Obstetrics and Gynecology.
authors: Kazuya
authors: K
authors: Mimura
authors: Department of Obstetrics and Gynecology.
authors: Takeshi
authors: T
authors: Kanagawa
authors: Department of Obstetrics and Gynecology.
authors: Masayuki
authors: M
authors: Endo
authors: Department of Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka.
authors: Tomomitsu
authors: T
authors: Miyoshi
authors: Department of Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka.
authors: Yasushi
authors: Y
authors: Okamura
authors: Kinki Block Blood Center, Japanese Red Cross, Osaka, Japan.
authors: Yoshihiko
authors: Y
authors: Tani
authors: Department of Hematology and Oncology.
authors: Yoshiaki
authors: Y
authors: Tomiyama
authors: Department of Obstetrics and Gynecology.
authors: Tadashi
authors: T
authors: Kimura
mesh_terms: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2 / Q000032:analysis / Q000276:immunology* / Q000378:metabolism; D000328:Adult; D000751:Anemia, Neonatal / Q000209:etiology / Q000276:immunology*; D000818:Animals; D001789:Blood Group Antigens / Q000276:immunology; D002415:Cats; D002478:Cells, Cultured; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D005312:Fetal Blood / Q000166:cytology; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D009363:Neoplasm Proteins / Q000032:analysis / Q000276:immunology* / Q000378:metabolism; D011247:Pregnancy; D055815:Young Adult
chemical_list: C116614:ABCG2 protein, human; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D001789:Blood Group Antigens; D009363:Neoplasm Proteins