TABLE 1.

Cases referred because of NAIT

Case	Para/gravida	Sample: month of gestation	HPA-1 type of father	HPA-1 type of infant	PLT nadir (×109/L)	Bleeding symptoms	Prenatal Rx	Postnatal therapy	Days to recovery (>100 × 109/L)	DRB3 * 0101	HLA abs	Comments
1	2/1	5	NT	NA	141	None	IVIG	None	NA	Positive	Positive	First infant had severe NAIT. No serologic studies done.
2	1/1	9	HPA-1a/a	HPA-1a/b	26	Petechiae 3+		Maternal PLT Tx ×1	5	Negative	Negative
3	2/2	9	HPA-1a/b	NA	38	None		PLTs, IVIG	NA	Negative	Positive	First child had “mild” TP. No studies done. Second child had “poor” response to PLT Tx, then responded to IVIG.
4	1/1	9	HPA-1a/b	NA	38	Petechiae 2+		None	4	Negative	Positive
5	2/2	9	HPA-1a/a	HPA-1a/a	18	Petechiae 1+		Exchange Tx PLT Tx	10	Negative	Negative	D immunization detected during second pregnancy. Anemic (DAT positive) and thrombocytopenic at birth.
6	2/1	6	HPA-1a/b	HPA-1b/b	200	None		None	NA	Negative	Negative	Previous child by a different father had severe NAIT and ICH leading to disability. Second child had normal PLTs at birth. Typing showed it was HPA-1a negative and first child was HPA-1a positive.
7	1/1	9	HPA 1a/a	HPA 1a/b	61	Petechiae 2+		None	10	Negative	Positive	Second child born 2 years later had petechiae and PLTs 61 × 109/L at birth. Recovered in 3 days without Rx. No serologic studies done.
8	1/1	9	HPA-1a/a	HPA-1a/b	8	Petechiae 2+		Maternal PLT Tx ×8	70	NA	Negative	Maternal PLT Txs given ×5 over 10 weeks produced good PLT increments but counts dropped to <30 × 109/L over 3–6 days. Not clear whether maternal PLTs were adequately washed.

abs = antibodies; NA = not available; NT = not tested; Rx = prescription; Tx = transfusion.