Efficiency of allogeneic hematopoietic SCT from HLA fully-matched non-sibling relatives: a new prospect of exploiting extended family search.

The best donors for hematopoietic SCT (HSCT) are fully-matched siblings. In patients without fully-matched siblings, HLA registries or cord blood banks are alternative strategies with some restrictions. Owing to the high rate of consanguineous marriage in our country, between 2006 and 2013, extended family searches were undertaken in Hematology-Oncology Research Center and Stem Cell Transplantation (HORCSCT), Tehran, Iran, in 523 HSCT candidates with parental consanguinity and no available HLA identical sibling. Fully-matched other-relative donors were found for 109 cases. We retrospectively studied the HSCT outcome in these patients. Median time to neutrophil engraftment was 13 days (range: 9-31days). In 83 patients, full chimerism and in 17 patients, mixed chimerism was achieved. Acute GvHD (aGvHD) grade II-IV appeared in 36 patients (33%). The frequency of aGvHD development in various familial subgroups was NS. Five patients expired before day+100. In the surviving 104 cases, chronic GvHD developed in 20 patients (19.2%). The distantly related subgroup had significantly a higher rate of cGvHD (P=0.04). The 2-year OS and disease-free survival (DFS) were 76.7±4.5% and 71.7±4.7%, respectively. No significant difference in OS (P=0.30) and DFS (P=0.80) was unraveled between various familial relationships. Our considerable rate of fully-matched non-sibling family members and the favorable outcome support the rationale for extended family search in regions where consanguineous marriage is widely practiced.