Neonatal alloimmune thrombocytopenia caused by an antibody specific for a newly identified allele of human platelet antigen‐7

Abstract

We identified a new third allele of HPA-7, which is characterized by a 1297C>T mutation in the GPIIIa gene. This 1297C>T allele was found in 0.15% of the Japanese population. An antibody against this antigen could be the cause of severe NAIT.

Maternal HLA Panel-Reactive Antibodies in Early Gestation Positively Correlate with Chronic Chorioamnionitis: Evidence in Support of the Chronic Nature of Maternal Anti-fetal Rejection

“…In humans, neonatal alloimmune neutropenia (NAIN) and neonatal alloimmune thrombocytopenia (NAIT) are well-known examples of alloimmune reactions, typically presenting against paternal/fetal antigens such as human neutrophil antigens 92,93 and human platelet antigens. 94,95 Interestingly, cases of NAIN and NAIT associated with maternal HLA class I antibodies have also been well-documented, indicating that HLA sensitization of the mother is a mechanism of disease in the fetus. 96–99 …”

Establishment of a cell line panel for the detection of antibodies against human platelet antigen 4b

“…HPA-1, HPA-4, HPA-6, HPA-7, HPA-8, HPA-10, HPA-11, HPA-14, HPA-16, HPA-17, HPA-1 variant, and HPA-7 variant [11] that are located on GPIIIa. They form a complex with GPIIb on the surface of the platelet and play an important role for platelet aggregation.…”

“…Therefore, the detection of these antibodies is important for diagnostic purposes. A variety of HPAs have been identified with a single amino acid substitution (18 cases) and an amino acid deletion in the platelet glycoproteins [2,[10][11][12][13]. As described in the Immuno Polymorphism Database (IPD) website (http://www.ebi.ac.uk/ipd/hpa/) [14], the frequency of HPA differs significantly among ethnic groups.…”

A new platelet alloantigen, Swia, located on glycoprotein Ia identified in a family with fetal and neonatal alloimmune thrombocytopenia

“…9,10 Recently, a new rare alloantigen Hit a on GPIIIa, associated with FNAIT, has been reported. 12 The Hit a alloantigen is interesting because it represents the third immunogenic allele of the HPA-7 system and was found in 0.15% of the Japanese population. 12,13 Third alleles of the HPA-1 and HPA-5 systems have already been described; however, alloantibody formations against these third allelic isoforms were not observed so far.…”

“…12 The Hit a alloantigen is interesting because it represents the third immunogenic allele of the HPA-7 system and was found in 0.15% of the Japanese population. 12,13 Third alleles of the HPA-1 and HPA-5 systems have already been described; however, alloantibody formations against these third allelic isoforms were not observed so far. 14,15 In this study, we describe a case of the fatal FNAIT caused by hydrocephalus as a consequence of massive intracranial bleeding.…”