[HPA-5b neonatal allo-immune thrombocytopenia: two cases described in Tunisia]. / Thrombopénies néonatales dues à un allo-anticorps anti-HPA-5b: à propos de deux cas observés en Tunisie.

UNLABELLED: Alloimmune thrombocytopenia is due to feto-maternal incompatibility in the HPA systems and is usually considered in the diagnosis of neonatal thrombocytopenia after other causes have been excluded. We report on two Tunisian observations of alloimmune neonatal thrombocytopenia due to anti-HPA-5b (Bra) antibodies. CASE REPORT: Two neonates presented at birth with a thrombocytopenic purpura unexplained by usual causes of neonatal thrombocytopenia. Alloimmune neonatal thrombocytopenia was diagnosed by the determination of parental and neonatal platelets antigens phenotypes and by the presence of HPA-5b (antiBra) antibodies in maternal sera. A favourable evolution was obtained after maternal platelet transfusions. CONCLUSION: Alloimmune neonatal thrombocytopenia is a serious affection, which exposes to intracranial haemorrhage. These observations of HPA-5 neonatal alloimmunisation in Tunisia provide additional information on the geographic distribution of the disease and its prognosis.