Treatment of Hemophagocytic Lymphohistiocytosis (HLH)

Initial Treatment Algorithm

For HLH, the American Society of Hematology recommends initiating high-dose pulse methylprednisolone 1 g/day IV for 3-5 consecutive days as first-line therapy, escalating to dexamethasone 10 mg/m² plus etoposide for severe disease with imminent organ failure, and adding cyclosporine A (2-7 mg/kg/day) or anakinra (2-10 mg/kg/day SC) for inadequate steroid response 1, 2
The initial treatment for mild-to-moderate HLH involves starting with prednisolone 1-2 mg/kg/day or dexamethasone 5-10 mg/m² for patients without organ failure, with the addition of IVIG 1.6 g/kg divided over 2-3 days for anti-inflammatory effects 1, 2
For severe HLH with imminent organ failure, immediately administer dexamethasone 10 mg/m² combined with etoposide using the modified HLH-94 protocol, and continue etoposide-based therapy for 8 weeks with weekly reassessment of need for continued treatment 1, 2

Add cyclosporine A 2-7 mg/kg/day with careful drug level monitoring if inadequate response to pulse steroids within 24-48 hours, as recommended by the American Society of Hematology 1, 4
Consider anakinra 2-10 mg/kg/day SC in divided doses, particularly for MAS-HLH or sepsis patients with MAS features, with a strength of evidence based on clinical experience 1, 4

For MAS-HLH (rheumatologic disease-associated), high-dose pulse methylprednisolone 1 g/day for 3-5 days remains first-line, with escalation to cyclosporine A or anakinra rather than etoposide when possible 4
In malignancy-associated HLH, treat the underlying malignancy concurrently with HLH-directed therapy, using disease-specific chemotherapy protocols that may include myeloablative conditioning, as recommended by the National Comprehensive Cancer Network 1, 2

Administer prophylaxis against Pneumocystis jirovecii, fungi, and viruses throughout HLH treatment due to severe T-cell depletion, as recommended by the Infectious Diseases Society of America 1
Monitor for secondary infections as a major cause of mortality during chemotherapy, with a high level of evidence based on clinical trials 1

After initial 8-week treatment, patients with residual disease benefit from maintenance therapy with corticosteroids and cyclosporine, as recommended by the American Society of Hematology 1, 2
Allogeneic stem cell transplantation is required for cure after achieving disease control in primary (genetic) HLH, with a high level of evidence based on clinical trials 2

Do not delay etoposide in severe HLH with organ failure—mortality increases significantly with treatment delay, with a high level of evidence based on clinical trials 1
Avoid applying pediatric HLH-2004 protocols directly to adults without dose modifications, as recommended by the American Society of Hematology 5