Down syndrome with neonatal alloimmune thrombocytopenia due to anti-HLA A31 and B61 antibodies

• Published in: International journal of hematology Vol. 113; no. 6; pp. 945 - 949
• Main Authors: Shima, Eriko, Go, Hayato, Maeda, Hajime, Ogasawara, Kei, Imamura, Takashi, Sasaki, Mutsumi, Koh, Yangsook, Nollet, Kenneth E., Ikeda, Kazuhiko, Ohto, Hitoshi, Hosoya, Mitsuaki
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 01.06.2021; Springer Nature B.V
• Subjects: Antibodies; Antigens; Case Report; Case reports; Complications; Down syndrome; Down's syndrome; Fetuses; Gestation; Hematology; Histocompatibility antigen HLA; Incompatibility; Intravenous administration; Leukocytes; Medicine; Medicine & Public Health; Myelopoiesis; Neonates; Newborn babies; Oncology; Platelets; Thrombocytopenia; Tissue typing; Neonatal alloimmune thrombocytopenia; Down syndrome; Human leukocyte antigen; Human platelet antigen
• ISSN: 0925-5710; 1865-3774
• DOI: 10.1007/s12185-021-03092-z

Neonatal alloimmune thrombocytopenia (NAIT) arises from fetomaternal platelet incompatibility that results in transplacental passage of maternal antibodies mostly against fetal human platelet antigens (HPA), whereas NAIT due to anti-human leukocyte antigen (HLA) antibodies is extremely rare. Here, we report a case of Down syndrome (DS) with NAIT that was attributed to HLA antibodies. A boy with DS was delivered at 36 weeks’ gestation. His platelet count declined to 13.0 × 10 9 /L, suggestive of NAIT rather than other conditions, including transient abnormal myelopoiesis. Random platelet concentrates and intravenous immunoglobulin administration resolved the thrombocytopenia without clinical complications. Immunoserological investigations detected anti-HLA, but no anti-HPA antibodies in samples from the patient and the mother. HLA typing and cross-matching indicated that anti-HLA antibodies to paternal HLA A31 and B61, which had probably been induced during a prior pregnancy, led to NAIT in this case. Although it is a rare condition, healthcare providers should consider NAIT due to HLA antibodies and be vigilant for subsequent cases in DS.