 2.5. Between May 2008 and May 2009, 31 additional patients with acute leukemia were treated with HLA-mismatched HCT using the same treatment strategy as in the aforementioned study. As such, the data of 52 patients are now available. There were 24 male and 28 female with median age of 39.5 years range, 16-70. Thirty-seven patients had AML, 13 ALL, and 2 acute mixed lineage leukemia. Ten patients were in first CR status, 15 in second or third CR status, and 27 had refractory disease. The donors were either offsprings n23, mothers n16, or siblings n13 of the patients and their median age was 37 years range, 3-68. The conditioning regimen for HCT included busulfan in reduced-dose, fludarabine, and antithymocyte globulin. GVHD prophylaxis was given with cyclosporine and methotrexate. Other than 4 patients who experienced leukemia progression within 30 days of HCT or died early, all the rest 48 patients achieved donor cell engraftment with absolute neutrophil count ANC 500μl on median 14.5 days range, 10-27. One patient experienced secondary graft failure subsequently. Cumulative incidence rates for acute GVHD grade 2-4 and chronic GVHD were 10 95 CI, 4-23 and 33 95 CI, 22-51, respectively. Cumulative incidence rates of leukemia progressionrecurrence were 13, 41, and 77 for patients in CR1, CR2-3, and refractory leukemia at the time of HCT. In all, five patients in the series died without leukemia progressionrecurrence giving transplantation-related mortality TRM rate of 12 95 CI, 5-29. Kaplan-Meier event-free survival and overall survival rates were 44 and 50 for patients in CR1 at HCT, 40 and 23 for patients in CR2-3, and 10 and 15 for patients with refractory leukemia. These results showed that HCT from an HLA-mismatched family member can be performed in patients with acute leukemia successfully without increased GVHD or TRM. 