Allogenic Stem Cell Transplantation in Amegacaryocytosis : Results of a Retrospective Study in EBMT Centers

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.