Clinical features and treatment of Langerhans cell histiocytosis

Area of Science:

• Immunology
• Oncology
• Genetics

Background:

• Langerhans cell histiocytosis (LCH) is a rare disorder characterized by the abnormal proliferation of CD1a+/CD207+ cells.
• The disease affects all age groups and can involve multiple organs, with liver, spleen, and hematopoietic system involvement significantly impacting survival.

Purpose of the Study:

• To review the pathogenesis, clinical presentation, and current treatment strategies for Langerhans cell histiocytosis (LCH).
• To highlight challenges in LCH management, including disease reactivation and long-term effects in survivors.

Main Methods:

• Literature review of studies on Langerhans cell histiocytosis (LCH) focusing on pathogenesis, clinical features, and therapeutic outcomes.
• Analysis of the role of MAPK pathway mutations, particularly BRAFV600E, in LCH development and treatment response.

Main Results:

• LCH pathogenesis is linked to MAPK pathway activation, with BRAFV600E mutations found in approximately two-thirds of cases.
• Risk-adapted treatment strategies are employed, with systemic chemotherapy for multi-system disease. Survival is excellent for patients without organ dysfunction but mortality can reach 20% with organ involvement.
• BRAF/MEK inhibitors show promise for immediate response but are associated with high reactivation rates upon discontinuation; their role in combination therapies is under investigation.

Conclusions:

• LCH management requires risk-adapted approaches, and while targeted therapies offer initial benefits, challenges with disease reactivation and long-term sequelae persist.
• Further research is needed to establish effective second-line treatments and address the long-term health challenges faced by LCH survivors, including neuroendocrine and neurodegenerative issues.