Objective:

To review the use of hematopoietic stem cell transplantation (HSCT) and cellular therapies for treating severe and refractory autoimmune diseases (ADs), emphasizing the significance of HSCT in improving patient outcomes and quality of life.

Key Findings:

• HSCT has become a standard treatment for severe ADs, particularly multiple sclerosis, systemic sclerosis, and Crohn’s disease.
• The EBMT registry is the largest database for HSCT in ADs, reporting over 3700 transplants.
• Improvements in HSCT outcomes are associated with increased experience and center size.
• Autologous HSCT is preferred for rapid hematopoietic recovery and involves the use of peripheral blood stem cells.
• The conditioning regimen's intensity varies and is crucial for minimizing treatment-related morbidity.

Interpretation:

HSCT shows promise in treating severe ADs by reconstituting a more tolerant immune system, but the optimal conditioning regimen remains to be defined due to patient variability, which can significantly affect treatment outcomes.

Limitations:

• Lack of direct comparative trials for conditioning regimens in ADs.
• Clinical heterogeneity of ADs complicates treatment standardization.
• Potential risks associated with HSCT, including infections, organ damage, and long-term effects that are not yet fully understood.

Conclusion:

HSCT represents a significant advancement in the treatment of severe autoimmune diseases, with ongoing research needed to optimize protocols, address patient variability, and improve long-term outcomes.