Review of neonatal alloimmune thrombocytopenia

Abstract

Neonatal alloimmune thrombocytopenia (NAIT), with an incidence of one in 1000 live births, is the most common cause of severe thrombocytopenia and intra-cerebral haemorrhage in term neonates. NAIT results from trans-placental passage of maternal antibodies against a paternally derived fetal platelet alloantigen. Clinical presentation varies from unexpected thrombocytopenia on a blood film in a well newborn to intracranial haemorrhage (ICH). In contrast to haemolytic disease of the newborn, NAIT can present in a first pregnancy, and subsequent pregnancies are usually more severely affected. The role of antenatal screening for maternal alloantibodies instead of fetal blood sampling to identify at-risk fetuses remains uncertain, but there is a trend towards less invasive maternally directed treatment for at-risk pregnancies. Neonatal management is aimed at preventing or limiting thrombocytopenic bleeding with transfusion of antigen-matched platelets.

Incidence and Consequences of Neonatal Alloimmune Thrombocytopenia: A Systematic Review

“…1,2 A major cause of isolated severe thrombocytopenia in term neonates is neonatal alloimmune thrombocytopenia (NAIT), 3 with an incidence of 1 in 1000 live births. 4 In NAIT, platelet destruction is caused by maternal immunoglobulin G allo-antibodies formed during pregnancy because of incompatibility of maternal and fetal (thus paternal) antigens on the platelet' s surface. In Caucasians, 85% of immunizations are caused by alloantibodies against human platelet antigens (HPA) 1a, commonly acquired during pregnancy 5 NAIT can be diagnosed either after clinical bleeding symptoms in the neonate or after detection of a fetal intracranial bleeding on ultrasound examination.…”

A rare manifestation of neonatal alloimmune thrombocytopaenia

“…NAIT is a rare and severe condition which should be suspected in case of a severe thrombocytopaenia in the first 72 h of life 2 6. A careful clinical history including maternal and familial background as well as investigation of other causes of neonatal thrombocytopaenia is absolutely essential,7 since although the mother can be asymptomatic, she or a sister may have a history of previous affected newborns 8…”

“…While signs of skin bleeding (petechiae or bruising) are the most common symptoms, NAIT can also lead to lung or gastrointestinal bleeding as well as intraocular and retinal haemorrhage (7%) 6 7. However, isolated intraocular haemorrhage is rare.…”

Avances en terapia fetal

“…[21][22] Cuando es grave (plaquetas< 50 000/ml) 23,24 puede ocasionar hemorragia intracraneal (HIC) en 10% de los casos 25 y causar la muerte o daño neurológico grave. 23,26 El tratamiento habitual de efectuar cesárea electiva y transfusión de plaquetas en la etapa postnatal o la transfusión fetal seriada de plaquetas 25,27 ha sido reemplazado por la administración de inmunoglobulinas a la madre entre las semanas 20 y 32 de gestación, con una tasa de éxito cercana al 100%, en términos de ausencia de HIC.…”

“…27 En las embarazadas con un hijo previo con HIC el tratamiento podría comenzarse antes: entre las 12 a 16 semanas. 24,[26][27][28] También se describen beneficios con el tratamiento de prednisona, sola o asociada a las inmunoglobulinas.…”