Title: Allogenic Stem Cell Transplantation in Amegacaryocytosis : Results of a Retrospective Study in EBMT Centers
Abstract: Allogenic stem cell transplantation is the only curative option for patients with inherited bone marrow failure syndrome such as congenital amegakaryocytic thrombopenia disease (CAMT). This multicenter retrospective study is based on data reported to the EBMT registry on patients with CAMT who underwent allogeneic hematopoietic stem cell transplantation from 1987 to 2013. Sixty three patients with CAMT were transplanted with identical sibling donor (n=25), matched unrelated donor (n=25), matched other relative (n=5) and mismatched donor (n=8). Stem cell source were bone marrow (n=31) or peripherical blood (n=21) or cord blood (n=11). Age at HSCT varied from 6 months to seventeen years. Conditioning regimen was available for 50 patients : 41 (82%) patients received myeloablative conditioning regimen and 9 (18%) patients reduced intensity one. The median time for neutrophil recovery was nineteen days. Cumulative incidence of grade II-IV aGvHD was 13%. Cumulative incidence of chronic extensive GvHD was 6.3%. 5 year-overall survival was 76.6%+/-7 and TRM is 12.6%+/-4 with no difference by age, gender, year of transplant, HLA compatibility and stem cell source. 53 (84%) patients were alive at last follow up. Nine patients (14.3%) died, seven from HSCT, one from disease and two from other causes. Eleven patients underwent second HSCT and six patients third HSCT. From them, four patients died and seven were alive, six were free of disease and one still with CAMT. This study is the wider reported so far and confirms that CAMT in children can successfully be treated by allogenic stem cell transplantation. Patients who lack a suitable related match have to be considered for alternative HSCT.