title: Anti-annexin A2 IgM antibody in preterm infants: its association with chorioamnionitis.
abstract: Intrauterine infection is associated with chorioamnionitis (CAM), which can lead to preterm delivery. We previously reported that the levels of IgM and the incidence of CAM were elevated in preterm infants with neonatal pulmonary emphysema. The pathogen and target of this IgM remain unclear. By using Western blot and amino acid sequences, we have determined one of the target proteins: annexin A2. Immunohistochemical analysis showed that annexin A2 was expressed at fetal chorion and amnion membranes. Among very low birth weight (VLBW) infants with hyper-IgM (> or = 30 mg/dL), 58.8% showed a high titer against annexin A2 (more than x 16), which accounted for about 20%-40% of the total IgM. Anti-annexin A2 IgM antibody inhibited plasmin generation. Furthermore, the median of anti-annexin A2 IgM titer from preterm infants who were delivered with high-grade (grade III) CAM was significantly higher than those from preterm infants without CAM (p = 0.011) and with low-grade CAM (grade I and II) (p = 0.010). Here, we indicate the fetal autoimmunoreactivity against the fetomaternal interface in preterm infants.
authors.affiliation: Department of Developmental Infectious Diseases, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka 594-1101, Japan.
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Namba
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kitajima
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tabata
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nakayama
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Suehara
authors.forename: Katsura
authors.initials: K
authors.lastname: Matsunami
authors.forename: Keiko
authors.initials: K
authors.lastname: Yanagihara
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nishihara
authors.forename: Akihiro
authors.initials: A
authors.lastname: Morita
authors.forename: Minoru
authors.initials: M
authors.lastname: Yamada
authors.forename: Akihito
authors.initials: A
authors.lastname: Kimoto
authors.forename: Shinya
authors.initials: S
authors.lastname: Hirano
authors.forename: Kiyotoshi
authors.initials: K
authors.lastname: Sekiguchi
authors.forename: Masanori
authors.initials: M
authors.lastname: Fujimura
authors.forename: Itaru
authors.initials: I
authors.lastname: Yanagihara
mesh_terms: D000595:Amino Acid Sequence; D017306:Annexin A2 / Q000032:analysis / Q000276:immunology* / Q000378:metabolism; D002821:Chorioamnionitis / Q000097:blood / Q000209:etiology / Q000276:immunology*; D005260:Female; D005341:Fibrinolysin / Q000037:antagonists & inhibitors; D006801:Humans; D007075:Immunoglobulin M / Q000032:analysis / Q000097:blood*; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood / Q000276:immunology*; D019102:Infant, Very Low Birth Weight / Q000097:blood / Q000276:immunology; D008969:Molecular Sequence Data; D010920:Placenta / Q000737:chemistry / Q000378:metabolism; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000276:immunology
chemical_list: D017306:Annexin A2; D007075:Immunoglobulin M; D005341:Fibrinolysin