Yasushi Takahata1, Hidetoshi Takada1, Akihiko Nomura1, Hideki Nakayama1, Koichi Ohshima2, Hitoo Nakano3, Toshiro Hara1.
Department of pediatrics1 and Gynecology and Obstetrics3, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
2The First Department of Pathology, School of Medicine, Fukuoka University, Fukuoka, Japan

We analyzed IL-18 levels of human milk. Colostrum contained significantly higher levels of IL-18 compared with early milk and mature milk. By stepwise multiple linear regression analysis, preterm delivery and pregnancy complications of mothers significantly correlated with high levels of IL-18 in human milk (p=0.0007 and 0.0018, respectively).  There was a significant correlation between the levels of IL-18 and soluble Fas ligand (sFasL) in colostrum (p=0.0003). IL-18 was detected in actively secreting epithelial cells in lactating mammary gland by immunohistochemical staining. These results suggest that IL-18 in colostrum plays an important role in host defense of high-risk neonates.