OBJECTIVETo investigate the impact of immunosuppressive therapy (IST) on genetic instabilities of bone marrow hematopoietic cells (BMHCs) in patients with aplastic anemia (AA).

METHODSComet assay as used to detect genetic instabilities of hematopoietic cells from patients, and the percent of DNA in comet tail (TDNA), tail length (TL), tail moment (TM), olive tail moment (OTM) and the rate of comet cells were measured. BMHCs from AA patients were examined with comet assay before and after IST, and the results were compared with those from controls.

RESULTSComet parameters from 91 AA patients including TDNA, TL, TM, OTM comet cell percentage were (5.0 +/- 4.0)%, 11.3 +/- 7.2, 1.7 +/- 2.0, 1.5 +/- 1.4, (16.8 +/- 13.7)%, respectively, which were significantly higher than those from control group (P < 0.05). There were statistical differences between the comet parameters of severe AA (SAA)/non-SAA (NSAA) and those of control group (P < 0.05), but no difference in the comet parameters between SAA and NSAA patients (P > 0.05). The TDNA, TL, TM, OTM and comet cells percentage were (4.4 +/- 3.6)%, 10.4 +/- 7.5, 1.4 +/- 1.6, 1.3 +/- 1.4 and (20.2 +/- 21.2)%, respectively at 3 months after IST in 53 SAA patients and were (3.7 +/- 3.3)%, 10.0 +/- 7.2, 1.2 +/- 1.8, 1.1 +/- 1.3 and (18.5 +/- 19.0)% respectively at 6 months after IST in 30 SAA patients, being no statistical difference from those of 58 SAA patients before IST (P values were all > 0.05).

CONCLUSIONBMHCs of AA had inherent genetic instabilities which were not increased by recent IST. It indicated that there was no correlation between IST and the development of clonal hematologic disorders in AA.