HPA-13bw neonatal alloimmune thrombocytopenia and low frequency alloantigens: case report and review of the literature.
BACKGROUND
Fetal-neonatal alloimmune thrombocytopenia (FNAIT) linked to rare or private antigens is not a rare event.


METHODS
Such a case discovered during the follow-up of a second child with jaundice with mild thrombocytopenia is reported here. Platelet (PLT) genotyping was performed by polymerase chain reaction (PCR)-sequence-specific primers method and PCR-restriction fragment length polymorphism (RFLP) analysis. Serologic investigation was done with the monoclonal antibody-specific immobilization of PLT antigens technique. Glycoprotein Ia-specific amplification and sequencing were performed for the polymorphism 807 (exon 7).


RESULTS
The mother was found to be HPA-13aaw, and the father HPA-13abw. A maternal alloantibody directed against HPA-13bw has been characterized, leading to the diagnosis of neonatal alloimmune thrombocytopenia.


CONCLUSIONS
This report provides further evidence that NAIT associated with low-frequency antigens is not restricted to single families. Therefore, laboratory investigation of a suspected case should be carried out in a specialist laboratory well experienced in optimal testing to propose appropriate management for the index case and subsequent pregnancies.
Bertrand
Gerald
G
Platelet Immunology Unit, INTS, 6 rue Alexandre Cabanel, 75739 Paris Cedex 15, France.
Bianchi
Frederic
F
Alexandre
Marie
M
Quesne
Jeannine
J
Chenet
Christophe
C
Martageix
Corinne
C
Jallu
Vincent
V
Kaplan
Cecile
C
D000328:Adult; D000483:Alleles; D016824:Antigens, Human Platelet / Q000276:immunology*; D001792:Blood Platelets / Q000276:immunology; D005091:Exons; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D039421:Integrin alpha2 / Q000235:genetics; D007519:Isoantigens / Q000276:immunology*; D011247:Pregnancy; D013921:Thrombocytopenia / Q000276:immunology*
D016824:Antigens, Human Platelet; D039421:Integrin alpha2; D007519:Isoantigens