Treatment of Erdheim-Chester disease with long-term high-dose interferon-α

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis, characterized by a foamy CD68+, CD1a- histiocyte tissue infiltration. Efficacy of standard doses of interferon-α-2a (IFNα) has been suggested in a small series but with variation, depending on the organs involved. Our aim was to report our single-center experience about the use of high-dose IFNα in ECD.

Twenty-four ECD patients have received high-dose IFNα (IFNα ≥18 mIU/wk or pegylated-IFNα ≥180 μg/wk). IFNα efficacy was evaluated clinically and morphologically using a standardized protocol (median follow-up 19 months).

Indication for treatment was central nervous system and/or heart involvement (n = 20), exophthalmos (n = 1), and standard-dose IFNα inefficacy (n = 3). High-dose IFNα was effective in 16 patients (67%) with improvement (n = 11, 46%) and stabilization (n = 5, 21%). Late and gradual improvement was observed during prolonged follow-up in most patients. The efficacy of high-dose IFNα was dependent on the organs involved: central nervous system and heart improvement or stabilization occurred in 7/11 (64%) and 11/14 (79%) patients, respectively. Six patients (25%) worsened. High doses of IFNα were well-tolerated: 13 (54.2%) patients had side effects but treatment interruption was infrequent (n = 3, 12.5%).

High-dose IFNα may be effective in severe ECD. Improvement may be slow, and high-dose IFNα treatment should be prolonged.