Clinical Implications of Abnormal Cytogenetics at Diagnosis of Aplastic Anemia.

Because cytogenetic abnormalities of aplastic anemia at diagnosis have been reported fairly infrequently, their clinical implications have not known yet. A retrospective study was performed of the cytogenetics findings and clinical courses in patients with typical morphological and clinical features of aplastic anemia from a single institution for the years 1995 through 2005. The results of chromosome analysis of 610 patients were evaluable. Of the evaluable patients, 584 (95.7 %) had normal karyotypes and 26 (4.3 %) had abnormal karyotypes at diagnosis. The most frequent abnormality was trisomy 8 (n=13) followed by deletion 1q (n=5) and monosomy 7/deletion 7q (n=5). Other chromosome abnormalities were isochromosome 17q (n=1), trisomy 15 (n=1) and monosomy 21 (n=1). Among the 584 patients with typical aplastic anemia and no cytogenetic abnormalities, only two developed MDS/AML during the follow-up period, while 5 (19.2%) of 26 patients with typical aplastic anemia and abnormal cytogenetics subsequently developed MDS/AML. The incidence of secondary MDS/AML was statistically higher in abnormal cytogenetics group compared with normal cytogenetics group (p<0.001). The incidence of secondary MDS/AML was not influenced by immunosuppressive therapy (IST) (p=0.715). The patients with trisomy 8 responded poorly to immunosuppressive therapy (IST) and showed statistically significant lower response rate compared with the patients with other cytogenetics (p=0.033). However, response rates of IST were not statistically different in the patients with normal cytogenetics group and the patients with abnormal cytogenetics other than trisomy 8 (p=1.000). Four patients with abnormal cytogenetics received allogeneic hematopoietic stem cell transplantations (allo-HSCT) with the same conditioning as the patients with normal cytogenetics. Three of them are still alive with normal peripheral blood counts. One of them died of acute GVHD and infection after successful engraftment. Our analysis suggested that cytogenetic abnormalities at diagnosis of aplastic anemia could be a risk factor for development of secondary MDS/AML and the patients with trisomy 8 at diagnosis of aplastic anemia might hardly respond to IST. Outcomes of allo-HSCT for aplastic anemia with abnormal cytogenetics probably are not different compared with aplastic anemia with normal cytogenetics.