日本未熟児新生児学会雑誌　第22巻　第2号　45～49頁（2010年）

日本未熟児新生児学会雑誌　22(2)：223-227；2010　

受付日：平成21．07．06

受理日：平成22．05．10

出生直後からのAST高値を契機に診断されたAST結合性免疫グロブリンの母児例

A Case of Neonate and His Mother with Aspartate Aminotransferase（AST） ― Immunoglobulin Complex Diagnosed for Elevated AST Activity in Serum Soon After Birth

＊1大阪市立住吉市民病院　新生児科，＊2大阪市立総合医療センター　小児内科

＊1 Department of Neonatology, Osaka City Sumiyoshi Hospital，＊2 Department of Pediatrics, Osaka City General Hospital

長谷川結子＊1＊2・郡山　健＊1・三浦夕子＊1 川又　攻＊1・金　太章＊1・舟本仁一＊1

Yuiko HASEGAWA＊1＊2，Takeshi KORIYAMA＊1，Yuko MIURA＊1， Osamu KAWAMATA＊1，Tae Jang KIM＊1，Hitokazu FUNAMOTO＊1

Key Words：AST-immunoglobulin complex，AST，immunoglobulin，neonate

　症例は男児で在胎40週6日，3,018gで出生した。日齢1に多呼吸，CRP上昇があり当院に入院となった。入院時，AST1,224IU/Lと高値を認めた。多呼吸，CRP上昇が落ち着いた日齢10になってもASTは804IU/Lと依然高値のままであった。ASTのアイソザイムを調べたところAST-IgGκλ複合体が認められ，AST結合性免疫グロブリンと診断された。母親についても原因不明のAST高値（100～130IU/L）が指摘されておりASTのアイソザイムを調べたところAST-IgGκ複合体がみられ，AST結合性免疫グロブリンと診断された。本例は新生児期に診断され，さらに母親も同疾患と診断できた非常に興味深い例であり，児のAST-IgGκλ複合体を構成するIgGは母体から経胎盤移行してきたIgGと思われた。母体から移行したIgGが消失してくることにより児のASTは1歳0ヵ月には54IU/Lと低下した。

　This neonate was a male baby weighing 3,018g born at 40 weeks and 6 days of gestation. He was hospitalized to our hospital since tachypnea and elevated CRP were recognized on day 1. At the time of hospitalization, AST activity in serum was 1,224 IU/L. On day 10, tachypnea and elevated CRP were improved, but AST was still as high as 804 IU/L. Therefore, we examined the isozyme of AST, and diagnosed him as having AST - immunoglobulin complex for the existence of AST-IgG κλ complex. As for his mother, unexplained AST elevation has been pointed out. An examination of the isozyme of AST revealed that she also had AST-IgG κ complex. So she was diagnosed as having ASTimmunoglobulin complex. This is a very interesting case that the neonate and his mother were diagnosed as having AST - immunoglobulin complex for elevated AST activity of the baby soon after birth. We presumed that IgG composing AST-IgG κλ complex of the baby was the IgG transferred placentally. At the age of 1 year and 0 month, AST of the baby fell to 54 IU/L as the maternal IgG disappeared.