More alternative donor stem cell transplantation (SCT) has been performed in recent years in China due to lack of HLA identical siblings. Higher risk for developing acute graft-versus-host disease (aGVHD) has been seen in patients who receive haploidentical stem cell transplantation (haplo-SCT) compared with identical sibling SCT patients (

Lu DP et al,
). In a murine model, we have first demonstrated that the animals transplanted with three mixed bone marrow (A+B+C to A) were survived longer due to milder aGVHD compared with the mice transplanted with single allogeneic bone marrow (B to A). In current clinical trial, we examine whether cord blood (CB) as the third party cells could reduce aGVHD in haplo-SCT setting under the same principle investigator in two hospitals. Between January 2006 and April 2008, total 133 haplo-SCT patients with hematological malignancies were enrolled. The patients with advanced diseases were excluded. All patients received unmanipulated blood and marrow transplant after BUCy2 or CyTBI plus antithymocyte globulin (ATG, Genzyme 10mg/kg) as preconditioning. Cyclosporine, short-term Methotrexate, and Mycophenolate mofetil were employed for GVHD prophylaxis. Fifty-six patients received one unit of HLA 3–6/6 matched CB one day before SCT as CB group, and 77 cases did not receive CB as control group. The main clinical characteristics in both groups are comparable. All patients in both groups achieved full donor chimerism. Low levels of CB chimerism were detected in a few patients at early stage after SCT. No long-term CB engraftment was found. The cumulative incidences of grade II to IV aGVHD were 16.4% versus 38.4% (p=0.008) in CB group, control group respectively. The cumulative incidences of grades III to IV aGVHD for CB group versus control group were 9.2% versus 22.4% with p=0.043. The incidences of 100-day treatment-related mortality were 1.8% versus 10.4% (p=0.053) for CB group, control group respectively. Our preliminary clinical study has shown that CB as the third party cells could significantly reduce the incidences of aGVHD, especially for severe aGVHD, and also treatment-related mortality in haplo-SCT. The mechanism of this strategy need to be further investigated.

Disclosures: No relevant conflicts of interest to declare.

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