日本新生児成育医学会雑誌　第28巻　第2号　67～71頁（2016年）

日本新生児成育医学会雑誌 28(2)：291-295；2016　

受付日：平成27．02．12

受理日：平成28．03．25

ラスブリカーゼが一過性骨髄異常増殖症の高尿酸血症に著効したダウン症候群の早産児例

Efficacy of Rasburicase for the Treatment of Hyperuricemia Due to Transient Abnormal Myelopoiesis in a Preterm Infant with Down Syndrome

東京女子医科大学母子総合医療センター　新生児医学科

Department of Neonatal Medicine, Maternal and Perinatal Center, Tokyo Women’s Medical University

末永英世・内山　温・岡村朋香・大野秀子・杉田依里・今井　憲・増本健一・戸津五月・中西秀彦・楠田　聡

Hideyo SUENAGA，Atsushi UCHIYAMA，Tomoka OKAMURA，Hideko OHNO，Eri SUGITA，Ken IMAI，Kenichi MASUMOTO，Satsuki TOTSU，Hidehiko NAKANISHI，Satoshi KUSUDA

Key Words：transient abnormal myelopoiesis，tumor lysis syndrome，
Down syndrome，hyperuricemia，rasburicase

　ラスブリカーゼはがん化学療法に伴う腫瘍崩壊症候群（tumor lysis syndrome：TLS）の高尿酸血症に対して使用される薬剤であるが，一過性骨髄異常増殖症（transient abnormal myelopoiesis：TAM）による高尿酸血症に対し単独で使用した報告は，我々が調べた範囲ではない。症例は在胎29週4日，出生体重2,106gの男児で，胎児水腫のため緊急帝王切開で出生した。全身の著明な浮腫，肝脾腫を認め，染色体検査でダウン症候群と診断された。芽球細胞を伴う白血球増多と高尿酸血症を認めたことから，TAM（GATA1遺伝子変異を認めた）による胎児水腫を疑った。高尿酸血症と尿量減少が持続したことから，TLSによる腎障害と判断し，日齢2から5に交換輸血を施行した。芽球細胞は減少したが，持続する高尿酸血症に対し日齢8からラスブリカーゼを2回使用したところ，速やかに改善し，明らかな副作用を認めなかった。ラスブリカーゼは，TAMによって化学療法施行以前にTLSを発症した高尿酸血症に対しても，支持療法の一つになり得ることが示唆された。

　A male infant weighing 2,106 g was delivered at 29 weeks and 4 days by emergency Cesarean section due to suspected hydrops fetalis caused by Rhesus incompatibility. The Apgar scores at 1 min and 5 min were 1 and 1, respectively. Blood examinations for the infant did not suggest immune hydrops fetalis but showed mild anemia and leukocytosis with circulating blast cells. Trisomy 21 was suspected due to the observed dysmorphic features. The patient showed markedly generalized edema with hepatosplenomegaly. Consequently, the clinical diagnosis was hydrops fetalis due to the transient abnormal myelopoiesis observed during the fetal period. Hyperuricemia and low urine output persisted. Hyperuricemic nephropathy was strongly suspected due to tumor lysis syndrome. We performed a blood transfusion exchange between Days 2 and 5. Following therapy, the blast cell count decreased. However, only a small transient decrease in serum uric acid level was observed. The uric acid level increased to 16.2mg/dL after 8 days of life. We prescribed 0.2mg/kg of rasburicase between Days 8 and 9 to reduce the uric acid level, which decreased considerably to less than 0.2mg/dL. No obvious side effects were observed during treatment. The definitive diagnosis was trisomy 21 confirmed by chromosomal analysis, and the infant also had a mutation in the GATA1 gene.
　In conclusion, rasburicase may become a potent supportive treatment against hyperuricemia due to tumor lysis syndrome in infants with transient abnormal myelopoiesis.