HLA-haploidentical blood progenitor cell transplantation in osteopetrosis

Area of Science:

• Pediatric Hematology
• Immunology
• Transplantation Medicine

Background:

• Infantile osteopetrosis (OP) is a rare genetic disorder with a poor prognosis without early intervention.
• Hematopoietic stem cell transplantation (HSCT) is the primary curative treatment for OP.
• Finding HLA-matched donors is challenging for many patients.

Purpose of the Study:

• To evaluate the efficacy and safety of HSCT using HLA-haploidentical peripheral blood progenitor cells in infants with OP.
• To determine the feasibility of using T-cell depleted grafts from parental donors.

Main Methods:

• Seven patients with infantile osteopetrosis lacking HLA-matched donors underwent HSCT.
• Peripheral blood progenitor cells were purified from HLA-haploidentical parents with T-cell depletion.
• Conditioning regimens included busulfan, thiotepa, and either cyclophosphamide or fludarabine.

Main Results:

• Stable donor engraftment was achieved in 6 out of 7 patients.
• No cases of graft-versus-host disease were observed.
• Five patients (71%) survived with a complete cure of OP at a median follow-up of 4 years, despite complications in some.

Conclusions:

• Transplantation of purified peripheral blood progenitor cells from HLA-haploidentical donors is a viable and effective treatment for infantile osteopetrosis.
• This strategy provides a crucial alternative for patients without suitable matched donors.
• Further research may optimize conditioning and supportive care to mitigate transplant-related complications.