Anti-annexin A2 IgM antibody in preterm infants: its association with chorioamnionitis.
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.
Namba
Fumihiko
F
Department of Developmental Infectious Diseases, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka 594-1101, Japan.
Kitajima
Hiroyuki
H
Tabata
Atsushi
A
Nakayama
Masahiro
M
Suehara
Noriyuki
N
Matsunami
Katsura
K
Yanagihara
Keiko
K
Nishihara
Masahiro
M
Morita
Akihiro
A
Yamada
Minoru
M
Kimoto
Akihito
A
Hirano
Shinya
S
Sekiguchi
Kiyotoshi
K
Fujimura
Masanori
M
Yanagihara
Itaru
I
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
D017306:Annexin A2; D007075:Immunoglobulin M; D005341:Fibrinolysin