日本新生児成育医学会雑誌　37(2)：83-90；2025　

日本新生児成育医学会雑誌　第37巻　第2号　83 ～ 90頁（2025年）

受付日：2025．02．03

受理日：2025．03．21

致死的経過を辿ったエコーウイルス11 型によるウイルス関連血球貪食性リンパ組織球症の早産児

Echovirus 11-Associated Hemophagocytic Syndrome with Fatal Course in Preterm Infant

日本赤十字社医療センター　新生児科

Department of Neonatology, Japanese Red Cross Medical Center

江口　脩・鵜川寿子・天方秀輔・中尾　厚

Shu EGUCHI，Toshiko UKAWA，Shusuke AMAGATA，Atsushi NAKAO

Key Words：hemophagocytic lymphohistiocytosis，virus-associated hemophagocytic syndrome，Echovirus 11

在胎34 週，出生体重1,995g の男児。日齢5 より無呼吸発作，日齢7 に肝機能障害，血小板減少を認め搬送された。 脾腫，汎血球減少，高フェリチン血症，高可溶性IL-2 受容体血症，播種性血管内凝固症候群を認めた。鼻咽頭ぬぐ い液，髄液よりエンテロウイルスが検出され，ウイルス関連血球貪食性リンパ組織球症と診断した。副腎皮質ステ ロイドと免疫グロブリン大量療法で治療を開始したが効果は限定的で，cyclosporine A が有効であった。入院時の 血清からエコーウイルス11 型（Echovirus 11：E-11）が同定された。血球貪食性リンパ組織球症としての病勢は抑 制できたものの，緊張性血胸や消化管出血などの重症な合併症の治療に難渋し敗血症を契機に永眠した。2024 年末， 国内から様々な合併症を伴う新しい変異系統株のE-11 の新生児重症例が報告されているが，以降，早産児例の報告 はいまだ存在しないため注意喚起を含めてここに報告する。

Echovirus 11 （E-11）, an RNA virus, is categorized as a nonpolio enterovirus, with a new mutant strain from Europe in 2022 ～ 2023 resulting in fatal neonatal infection. Hemophagocytic lymphohistiocytosis （HLH） is one of the severe symptoms caused by E-11. Moreover, HLH is a syndrome of pathologic immune activation and uncontrolled inflammation with high mortality in neonates. Here, we present a preterm infant with virus-associated hemophagocytic syndrome due to E-11 with a fatal course. A 34-week preterm male infant with a birth weight of 1,995 g with liver dysfunction, thrombocytopenia, and apneic episodes starting on day of life 5 was transferred to our neonatal intensive care unit on day of life 7. On admission, he had splenomegaly, pancytopenia, elevated ferritin and soluble IL-2 receptor levels, and disseminated intravascular coagulation syndrome. Multiplex polymerase chain reaction detected the presence of enterovirus in the nasopharyngeal swab and spinal fluid, and he was diagnosed with virus-associated hemophagocytic syndrome. Initially, the patient was treated with methylprednisolone pulse therapy and high-dose immunoglobulin, with limited improvement. Subsequently, he was treated with cyclosporine A and recovered from HLH. E-11 was identified from his serum submitted on admission. Although his HLH had improved, he developed severe complications, such as tension hemothorax and gastrointestinal hemorrhage, and eventually died following Escherichia coli sepsis. Severe neonatal infection of the new E-11 mutant strain with various complications was reported from Japan at the end of 2024. Since then, this is the first case report of an E-11 infection in a preterm infant.