TY - JOUR
T1 - Clinical characteristics of human platelet antigen (HPA)-1a and HPA-5b alloimmunised pregnancies and the association between platelet HPA-5b antibodies and symptomatic fetal neonatal alloimmune thrombocytopenia
AU - de Vos, Thijs W.
AU - Porcelijn, Leendert
AU - Hofstede-van Egmond, Suzanne
AU - Pajkrt, Eva
AU - Oepkes, Dick
AU - Lopriore, Enrico
AU - van der Schoot, C. Ellen
AU - Winkelhorst, Dian
AU - de Haas, Masja
N1 - Funding Information: We want to thank the laboratory of platelet and leukocyte serology at Sanquin, Amsterdam that collected the cohort of newly diagnosed FNAIT samples. Publisher Copyright: © 2021 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.
PY - 2021/11
Y1 - 2021/11
N2 - Fetal neonatal alloimmune thrombocytopenia (FNAIT) is caused by maternal alloantibodies directed against the human platelet antigens (mostly HPA-1a or HPA-5b) of the (unborn) child and can lead to severe bleeding. Anti-HPA-1a-mediated FNAIT shows a severe clinical outcome more often than anti-HPA-5b-mediated FNAIT. Given the relatively high prevalence of anti-HPA-5b in pregnant women, the detection of anti-HPA-5b in FNAIT-suspected cases may in some cases be an incidental finding. Therefore we investigated the frequency of anti-HPA-5b-associated severe bleeding in FNAIT. We performed a retrospective nationwide cohort study in cases with clinical suspicion of FNAIT. HPA antibody screening was performed using monoclonal antibody-specific immobilisation of platelet antigens. Parents and neonates were typed for the cognate antigen. Clinical data were collected by a structured questionnaire. In 1 864 suspected FNAIT cases, 161 cases (8·6%) had anti-HPA-1a and 60 (3·2%) had anti-HPA-5b. The proportion of cases with severe bleeding did not differ between the cases with anti-HPA-1a (14/129; 11%) and anti-HPA-5b (4/40; 10%). In multigravida pregnant women with a FNAIT-suspected child, 100% (81/81) of anti-HPA-1a cases and 79% (38/48) of anti-HPA-5b cases were HPA-incompatible, whereas 86% and 52% respectively were expected, based on the HPA allele distribution. We conclude that anti-HPA-5b can be associated with severe neonatal bleeding symptoms. A prospective study is needed for true assessment of the natural history of anti-HPA-5b mediated FNAIT.
AB - Fetal neonatal alloimmune thrombocytopenia (FNAIT) is caused by maternal alloantibodies directed against the human platelet antigens (mostly HPA-1a or HPA-5b) of the (unborn) child and can lead to severe bleeding. Anti-HPA-1a-mediated FNAIT shows a severe clinical outcome more often than anti-HPA-5b-mediated FNAIT. Given the relatively high prevalence of anti-HPA-5b in pregnant women, the detection of anti-HPA-5b in FNAIT-suspected cases may in some cases be an incidental finding. Therefore we investigated the frequency of anti-HPA-5b-associated severe bleeding in FNAIT. We performed a retrospective nationwide cohort study in cases with clinical suspicion of FNAIT. HPA antibody screening was performed using monoclonal antibody-specific immobilisation of platelet antigens. Parents and neonates were typed for the cognate antigen. Clinical data were collected by a structured questionnaire. In 1 864 suspected FNAIT cases, 161 cases (8·6%) had anti-HPA-1a and 60 (3·2%) had anti-HPA-5b. The proportion of cases with severe bleeding did not differ between the cases with anti-HPA-1a (14/129; 11%) and anti-HPA-5b (4/40; 10%). In multigravida pregnant women with a FNAIT-suspected child, 100% (81/81) of anti-HPA-1a cases and 79% (38/48) of anti-HPA-5b cases were HPA-incompatible, whereas 86% and 52% respectively were expected, based on the HPA allele distribution. We conclude that anti-HPA-5b can be associated with severe neonatal bleeding symptoms. A prospective study is needed for true assessment of the natural history of anti-HPA-5b mediated FNAIT.
KW - alloimmune thrombocytopenia
KW - alloimmunisation during pregnancy
KW - human platelet antigen
KW - neonatology
UR - http://www.scopus.com/inward/record.url?scp=85112401874&partnerID=8YFLogxK
U2 - https://doi.org/10.1111/bjh.17731
DO - https://doi.org/10.1111/bjh.17731
M3 - Article
C2 - 34402048
SN - 0007-1048
VL - 195
SP - 595
EP - 603
JO - British journal of haematology
JF - British journal of haematology
IS - 4
ER -