neonatal alloimmune thrombocytopenia
Also written as: NAIT — neonatal alloimmune thrombocytopenia
A condition where maternal antibodies against fetal platelet antigens cause severe thrombocytopenia in newborns.
Full Definition
Neonatal alloimmune thrombocytopenia (NAIT) is a serious condition occurring when maternal antibodies directed against paternally inherited platelet antigens cross the placenta and destroy fetal platelets. The most commonly involved antigen is human platelet antigen 1a (HPA-1a). Unlike Rh disease, NAIT can occur in first pregnancies and often presents with severe thrombocytopenia (platelet count <50,000/μL) in otherwise healthy newborns. Clinical manifestations include petechiae, purpura, and potentially life-threatening intracranial hemorrhage. Diagnosis is confirmed by demonstrating maternal anti-platelet antibodies and paternal antigen positivity. Treatment includes platelet transfusions using maternal or antigen-negative donor platelets, and intravenous immunoglobulin.
Usage
Usage note: Commonly abbreviated as NAIT; may also be called FNAIT (fetal and neonatal alloimmune thrombocytopenia).
In Context
- "The newborn's severe thrombocytopenia and presence of maternal anti-HPA-1a antibodies confirmed neonatal alloimmune thrombocytopenia." — Neonatal intensive care note