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BACKGROUND:

Lack of human leucocyte antigen-matched family donors has restricted the application of hematopoietic cell transplantation. Due to immunological disorder of humam leucocyte antigen misfit, common way for haploidentical transplantation is associated with poor engraftment and severe graft-versus-host disease. Because not every patient has HLA-Jdentical family member, a substantial proportion of patients will receive haploidentical transplantation.

OBJECTIVE:

To explore the curative effect on malignant hematological diseases of haploidentical peripheral blood stem cell transplantation (PBSCT) using myeloablative conditioning regimen in combination of proper immunosuppressants without in vitro T-cell depletion. DESIGN, TIME AND

SETTING:

A case observation was performed at the Department of Hematology in the First Affiliated Hospital of Xinjiang Medical University from July 2002 to June 2008.

PARTICIPANTS:

Forty-two patients with malignant hematological diseases, including 29 standard-risk patients and 13 high-risk patients, age from 10 to 48 years, were transplanted with cells from a haploidentical family donor with 1-3 mismatched loci of HLA antigens. Seven patients had 1 locus mismatched donors and thirty-five patients had 2-3 loci mismatched donors.

METHODS:

The patients have received myeloablative conditioning regimen. A two-agent based graft-versus-host disease (GVHD) prophylaxis was used as cyclospodne A and a short course of methotrexate. Mycophenolate mofetile was added for 1 locus mismatched patients. Mycophenolate mofetile, antithymocyte globulin and CD25 mono-colonal antibody were added for 2-3 loci mismatched patients. The grafts were granulocyte colony-stimulating factor-mobilized peripheral blood stem cells without in vitro T-cell depletion. MAIN OUTCOME

MEASURES:

Engraftment, GVHD incidence and severity, relapse and leukemia-free survival and the immune function of patients in months 1, 3, 6, 12 and 18 postoperatively.

RESULTS:

Totally 42 patients achieved complete and sustained donor-type engraftment. Nineteen patients developed acute GVHD, the 2-year cumulative incidences of acute GVHD were 50.8%, gradeⅠ acute GVHD occurred in 16 cases and grade Ⅱ in 3 cases. Thirty-one patients were followed up more than 6 months, 23 of them developed chronic GVHD with limited in 20 and extensive in 3, the 2-year cumulative incidences of chronic GVHD were 57.1%. No patients died of GVHD. There were no significant differences in the reduction and recovery of T cells and B cells between HLA haploidentical PBSCT without in vitro T cell depletion and HLA-matched PBSCT.

CONCLUSION:

Haploidentical PBSCT is feasible and safe for malignant hematological diseases to use myeloablative conditioning regiment combination of intensive immunosuppressants without in vitro T cell depletion. A large amount of clinical cases need to be investigated in the near future.