The management of alloimmune neonatal thrombocytopenia.

Abstract

Neonatal alloimmune thrombocytopenia (NAITP), defined as thrombocytopenia (platelet count < 150 x 10(9)/l) due to transplacentally acquired maternal platelet alloantibodies, occurs in approximately 1 per 1200 live births in a Caucasian population. In such a population, the majority (> 75 percent) of cases are due to fetomaternal incompatibility for the platelet specific alloantigen, HPA-1a (P1A1, Zwa). Incompatibility for the HPA-5b (Bra) alloantigen is the next most frequent cause of NAITP in Caucasians; much less common is NAITP due to incompatibility for HLA, blood group ABO or other platelet-specific antigens. In non-Caucasian populations (e.g. Orientals) HPA-1a incompatibility is a rare cause of NAITP and other alloantigens e.g. HPA-4b (Penb, Yuka) are implicated. The greatest clinical challenge relates to the antenatal management of pregnant women alloimmunized to the HPA-1a (P1A1, Zwa) antigen, and particularly the subset of such women who have a history of a previously affected infant with severe thrombocytopenia and/or intracranial hemorrhage (ICH). The risk of antenatal ICH in the fetus of such women is high enough to merit intervention, either weekly infusion of high-dose intravenous immunoglobulin G (IVIG) with or without corticosteroids given to the mother (the preferred approach in North American centres), or repeated in-utero fetal platelet transfusions (the preferred treatment approach in some European centres). Post-natal management of severely affected infants centres on the rapid provision of compatible antigen-negative platelets harvested from the mother or a phenotyped donor. The value of antenatal screening programs to detect 'at risk' alloimmunized women during pregnancy continues to be debated.

• Authors: V S Blanchette, J Johnson, M Rand
• Journal: Bailliere's best practice & research. Clinical haematology (Baillieres Best Pract Res Clin Haematol) Vol. 13 Issue 3 Pg. 365-90 (Sep 2000) England
• PMID: 11030040 (Publication Type: Journal Article, Review)

Chemical References

• Adrenal Cortex Hormones
• Antigens, Human Platelet
• Immunoglobulins, Intravenous
• Isoantibodies
• Isoantigens

Topics

• Adrenal Cortex Hormones (therapeutic use)
• Antigens, Human Platelet (immunology)
• Blood Platelets (immunology)
• Female
• Humans
• Immunoglobulins, Intravenous (therapeutic use)
• Infant, Newborn
• Isoantibodies (immunology)
• Isoantigens (immunology)
• Maternal-Fetal Exchange
• Platelet Transfusion
• Pregnancy
• Thrombocytopenia (diagnosis, epidemiology, immunology, therapy)