Pretransplant analyses may help prevent the administration of unnecessary hematopoietic stem cell transplantation (HSCT) among pediatric patients with hemophagocytic lymphohistiocytosis (HLH), according to research published in Blood Advances.

Disease treatment for HLH aims to reduce hyperinflammation, which can mitigate sequelae among pediatric patients. To cure primary HLH, HSCT is required; this is also true of some forms of secondary HLH, notably those associated with chronic Epstein-Barr viral infection.

New treatment protocols, introduced over the last 25 years, have improved 5-year overall survival (OS) rates to about 54%. However, transplant-related mortality (TRM) remains a significant cause of death in this population.

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The HLH-2004 study, created by the Histiocyte Society, noted a 5-year OS rate of 64%, with notable improvements in pre-HSCT mortality compared with research conducted a decade previously. In the present paper, researchers enumerate clinical outcomes among pediatric patients who participated in HLH-2004.

Data from 187 patients younger than 18 years were included in the study; 90 (48%) patients were male, 124 (66%) were less than 1 year old, 91 (49%) were less than 1 year old when HSCT took place, 134 (72.7%) had confirmed familial HLH (FHL), and 53 (27.3%) did not have verified FHL.

Post-HSCT, the 5-year OS rate was 66% and 5-year event-free survival (EFS) was 60%. Among patients with a complete response, 5-year OS was 81%, compared with 59% among those with a partial response (hazard ratio [HR], 2.21; P =.035). Among patients with FHL, 5-year OS was 71%, while 5-year EFS was 62%.

Among those without verified FHL, 5-year OS was 52% (HR for survival, 1.69). Fourteen (26%) of these patients did not show evidence of biallelic mutations, though at least 3 genes associated with FHL were analyzed.

“We conclude that: (1) patients with nonverified FHL (possibly including [secondary] HLH cases) seem to do worse than verified FHL patients; (2) a thorough patient selection with pretransplant analyses, including confirmation of FHL, is recommended; and (3) pretransplant complete remission is beneficial but not mandatory to achieve post-HSCT survival,” the authors wrote.

Disclosures: Some authors have declared affiliations with or received funding from the pharmaceutical industry. Please refer to the original study for a full list of disclosures.


Bergsten E, Horne A, Hed Myrberg I, et al. Stem cell transplantation for children with hemophagocytic lymphohistiocytosis: results from the HLH-2004 study. Blood Adv. 2020;4(15):3754-3766. doi:10.1182/bloodadvances.2020002101