[Comparison of immune reconstitution at early stage after unmanipulated haploidentical stem cell transplantation between high- and standard- risk Philadelphia chromosome- negative acute lymphoblastic leukemia patients in CR1].

OBJECTIVE: To compare the early stage immune reconstitution of high- and standard-risk Philadelphia chromosome- negative acute lymphoblastic leukemia (ALL) CR1 patients who had haploidentical blood and marrow stem cell transplantation (HBMT).

METHODS: A total of 49 Ph-negative ALL CR1 patients who received HBMT and had complete early stage immune reconstitution data(+30, +60 and +90 d post transplantation) from Jan. 2010 to Dec. 2012 were enrolled. Immunophenotyping for B and T lymphocytes was performed post HBMT via flow cytometry. Fresh peripheral blood cells were stained with fluorochrome-labeled monoclonal antibodies against cluster of differentiation CD19, CD3, CD4, CD8, CD45RO, CD45RA and CD28. The early reconstitution of lymphocyte subsets, survival and prognosis between standard- risk group, high- risk adult group and high- risk children group were compared.

RESULTS: There were no significant differences in all these T lymphocyte subsets among three groups at the three check points (P>0.05). Moreover, at the same time, comparable outcome had been achieved between standard-risk group (n=18), high-risk adult group (n=16) and high-risk children group (n=15). There were no differences in 2- y relapse incidence (27.8% vs 31.3% vs 26.7%, P=0.957), 2- y non- relapse mortality (11.1% vs 0 vs 13.3%, P=0.185), 2- y leukemia free survival (61.1% vs 68.8% vs 60.0%, P=0.834) and overall survival (77.8% vs 68.8% vs 60.0%, P=0.529) among the three groups. Incidence of grade Ⅱ-Ⅳ aGVHD was 44.4% vs 12.5% vs 46.7% (P=0.075) and incidence of cGVHD was 61.1% vs 50.0% vs 40.0% (P=0.249).

CONCLUSION: Comparison of immune reconstitution at early stage may be a reasonable cause to explain that equivalent outcomes were observed among high- and standard- risk Ph- negative ALL CR1 patients after HBMT.