Exchange transfusion in patients with Down syndrome and severe transient leukemia.

Background: Among neonates with Down syndrome (DS) and transient leukemia (TL), hyperleukocytosis (white blood cell [WBC] count >100 × 10(9) /L) is associated with increased blood viscosity, respiratory failure due to pulmonary hypertension, multiorgan failure, and increased risk of early death. There have been no previous studies focusing on the effects of exchange transfusion (ExT) on WBC count, respiratory status, and other parameters in TL patients with hyperleukocytosis.

Methods: An observational retrospective study was carried out at a single center of all five DS neonates with TL, GATA1 mutations, and hyperleukocytosis, born at a median gestational age of 34 weeks (range, 30-38 weeks) with birthweight 2556 g (range, 1756-3268 g) during a 24 month study period between September 2011 and August 2013. All five neonates underwent ExT at a median age of 2 days (range, 0-5 days) before initiation of other cytoreductive therapy with cytarabine, which was carried out in two patients.

Results: All patients required respiratory support before ExT. After ExT, respiration status improved in all five patients: WBC count (mean) decreased by 85% from 143 × 10(9) /L to 21 × 10(9) /L. None developed tumor lysis syndrome. Three survived and two died: one hydrops fetalis neonate born at gestational week 30 died at age 5 days, and another died eventually from acute gastroenteritis 40 days after leaving hospital at the age of 155 days with complete remission. Two of the three surviving neonates developed acute megakaryocytic leukemia at age 90 days and 222 days.

Conclusion: ExT was very effective in improving hyperleukocytosis and may have had favorable effects on respiration.