HSCT may lower leukemia risk in ELANE neutropenia: a before-after study from the French Severe Congenital Neutropenia Registry.

ELANE neutropenia is associated with myelodysplasia and acute leukemia (MDS-AL), and severe infections. Because the MDS-AL risk has also been shown to be associated with exposure to GCSF, since 2005, in France, patients receiving high daily GCSF doses (>15 μg/kg/day) are eligible for HSCT, in addition to classic indications (MDS-AL or GCSF refractoriness). We analyzed the effect of this policy. Among 144 prospectively followed ELANE-neutropenia patients enrolled in the French Severe Congenital Neutropenia Registry, we defined two groups according to period: "before 2005" for those born before 2005 and followed until 31/12/2004 (1588 person-years); and "after 2005" comprised of those born after 2005 or born before 2005 but followed after 2005 until 31/03/2019 (1327 person-years). Sixteen of our cohort patients underwent HSCT (14 long-term survivors) and six developed MDS-ALs. Six leukemic transformations occurred in the before-2005 group and none after 2005 (respective frequencies 3.8 × 10 vs. 0; P < 0.01), while four HSCTs were done before 2005 and 12 since 2005 (respective HSCT rates increased 2.5 × 10 vs. 9 × 10; P < 0.01). Our results support early HSCT for patients with ELANE mutations who received high GCSF doses, as it might lower the risk of leukemic transformation.