日本新生児成育医学会雑誌　第30巻　第2号　96～100頁（2018年）

日本新生児成育医学会雑誌　30(2)：344-348；2018　

受付日：平成29．08．28

受理日：平成30．03．08

骨髄検査所見が診断に有用であった新生児同種免疫性好中球減少症の1 例

A Case of Neonatal Alloimmune Neutropenia Diagnosed via a Bone Marrow Examination

名古屋第二赤十字病院　小児科

Department of Pediatrics, Japanese Red Cross Nagoya Daini Hospital

近藤康宏・加藤　晋・笠置俊希・黒木亜津子・圓若かおり・廣岡孝子・横山岳彦・田中太平

Yasuhiro KONDO，Shin KATO，Toshiki KASAGI，Atsuko KUROKI， Kaori MARUWAKA，Takako HIROOKA，Takehiko YOKOYAMA，Taihei TANAKA

Key Words：neonatal alloimmune neutropenia，neutropenia，bone marrow examination， neutrophil-specific alloantibodies

　症例は，無呼吸発作のため日齢1 でNICU に入院となった女児である。入院時から著明な好中球減少症が遷延し，日齢13 に発熱するも好中球数が増加しなかったため，精査目的で骨髄穿刺を行った。骨髄所見より新生児同種免疫性好中球減少症が疑われ，母児の好中球抗原・抗体検査測定によって好中球のHNA（human neutrophil antigens） -Ⅰb 抗原を抗原とする新生児同種免疫性好中球減少症と診断が確定された。日齢29 に退院した後，抗菌薬の予防投与を行わずに経過を観察したが，重症感染症を起こすことなく生後2 か月で好中球減少症は自然軽快した。骨髄像では骨髄球系細胞の著明な過形成を呈し，骨髄球系の分化の過程で後骨髄球までの過形成と，杆状核球以降の低形成を認めた。これはヒト好中球特異抗原の発現時期が関係しており，骨髄穿刺が本疾患の補助診断として有用であった。

　The patient was a 1-day-old female who was admitted to the neonatal intensive care unit because of an apneic attack. The patient exhibited significantly prolonged neutropenia since admission. Although the infant was febrile at 13 days of age, the neutrophil count did not increase；therefore, a bone marrow examination was performed to evaluate the case in more detail. The bone marrow findings raised the suspicion of neonatal alloimmune neutropenia. The human neutrophil antigen-1b test based on the neutrophil antigen and antibody testing of the mother and child led to a definitive diagnosis of neonatal alloimmune neutropenia. Following discharge at 29 days of age, the patient was followed up without preventive administration of antimicrobial drugs；however, the patient underwent spontaneous remission of neutropenia without severe infections at 2 months of age. Myelograms revealed prominent myeloid hyperplasia, hyperplasia of metamyelocytes in the process of myeloid differentiation, and hypoplasia of stab and segmented neutrophils, which were related to the expression of human neutrophil-specific antigens. Therefore, the bone marrow examination was effective in aiding the diagnosis of this disease.