Heme-Onc

Question 1

What is the most common cause of severe thrombocytopenia in a well-appearing neonate?

Answer 1

The most common cause of severe thrombocytopenia (< 50 × 103/μL [50 × 109/L]) in a healthy-appearing neonate is neonatal alloimmune thrombocytopenia

Question 2

What is the most common cause of MILD thrombocytopenia in a well-appearing neonate?

Answer 2

Mild thrombocytopenia (50-149 × 103/μL [50-149 × 109/L]) in healthy-appearing neonates often occurs in patients affected by placental insufficiency associated with maternal pregnancy-induced hypertension and/or intrauterine growth restriction

Question 3

What is the pathophysiology of NAIT?

Answer 3

A mother with antigen-negative platelets becomes sensitized by antigen-positive platelets crossing the placental barrier. Antiplatelet antibodies of the immunoglobulin G class produced by the mother then cross the placenta and result in destruction of fetal platelets.

Question 4

Most common antigen associated with NAIT?

Answer 4

Among white infants, approximately 80% to 90% of cases of NAIT are associated with the human platelet antigen 1a (HPA-1a)

HPA-5b is responsible for 5% to 15% of cases.

Question 5

What is the difference between NAIT and autoimmune thrombocytopenia?

Answer 5

Autoimmune thrombocytopenia in the neonate is also caused by the transplacental passage of maternal antiplatelet immunoglobulin G.

Because the antibodies also affect maternal platelets, the mother’s platelet count is low.