HOOK

Haemophagocytic lymphohistiocytosis (HLH) is a rare but potentially life-threatening condition in which the immune system becomes excessively activated, causing widespread inflammation and organ damage. Early diagnosis and prompt treatment are critical to improving outcomes.

HISTORY / OVERVIEW

Hemophagocytic lymphohistiocytosis can occur as:

• Primary (familial) HLH: An inherited form caused by genetic mutations affecting immune cell function, often presenting in infancy or childhood.

• Secondary (acquired) HLH: Triggered by infections, autoimmune diseases, cancers (especially certain lymphomas), or other medical conditions.

Treatment aims to suppress the excessive immune response while addressing the underlying trigger.

TREATMENT APPROACHES

Immunosuppressive and Immunomodulatory Therapy

• Corticosteroids to reduce inflammation

• Chemotherapy-based regimens in appropriate patients

• Targeted immunomodulatory therapies for selected cases

• Intravenous immunoglobulin (IVIG) in certain clinical situations

Treating the Underlying Cause

• Antiviral, antibacterial, or antifungal therapy when infections are identified

• Treatment of associated autoimmune diseases

• Management of underlying malignancies such as lymphoma when present

Curative Therapy for Selected Patients

• Hematopoietic stem cell transplantation is considered for many patients with primary HLH and for selected patients with recurrent or treatment-resistant disease.

SUPPORTIVE CARE

Supportive treatment is an essential part of HLH management and may include:

• Blood transfusions when indicated

• Fluid and electrolyte management

• Nutritional support

• Intensive care monitoring for critically ill patients

• Prevention and treatment of secondary infections

• Management of liver, kidney, or neurological complications

BENEFITS OF EARLY TREATMENT

✔ Controls excessive immune activation✔ Reduces the risk of organ failure✔ Improves survival when treatment is started promptly✔ Addresses the underlying trigger when identified✔ Provides a pathway to long-term disease control or cure in eligible patients

PATIENT CARE TIPS

• Seek immediate medical attention for persistent high fever, unexplained fatigue, enlarged liver or spleen, unusual bleeding, or rapidly worsening illness.

• Follow the prescribed treatment plan closely and attend all follow-up appointments.

• Report new symptoms or signs of infection promptly, as immune-suppressing treatments can increase infection risk.

• Genetic counseling may be recommended for families affected by inherited HLH.

• Long-term monitoring by hematology and immunology specialists is often necessary.

FUTURE DIRECTIONS

Research is focused on:

• More targeted immune therapies

• Earlier diagnostic biomarkers

• Improved genetic testing

• Personalized treatment strategies

• Safer and more effective stem cell transplantation techniques

ENGAGEMENT QUESTION

Which advancement do you think could have the greatest impact on improving outcomes for HLH: earlier diagnosis, targeted immunotherapies, genetic testing, or advances in stem cell transplantation?