Sgt Idan Ducach gave a blood sample to Israeli charity Ezer Mizion when he enlisted in the IDF. Later he was told he was a bone marrow match for Alex – a young American boy. Idan donated his bone marrow and one year later met a very healthy Alex in New York.
http://www.idfblog.com/2012/12/15/saving-a-10-year-olds-life/