Abstract: BACKGROUND AND AIM: To explore mutations of PIG-A gene exon2, exon4, exon5 and expression of CD55 and CD59 in granulocytes of patients with aplastic anemia. MATERIALS AND METHODS: Genomic DNA from peripheral blood of 30 aplastic anemia patients and 20 normal controls were extracted, and PIG-A gene exon2, exon4, exon5 were then examined with polymerase chain reaction(PCR), nucleotide sequences were analyzed by bidirectional sequencing after PCR products were purified. The expressions of CD55 and CD59 in granulocytes from peripheral blood of the two groups above were detected by flow cytometry. RESULTS: The mutations of PIG-A gene exon2 including base substitution, deletion, insertion occurred in 11 of 30 aplastic anemia patients , the mutations of exon4, exon5 were also found in five aplastic anemia patients, with only base substitution. Two or more exon mutations were found in 5 aplastic anemia patients, but the normal controls had no in mutations. The expression of CD55 and CD59 were (86.57±5.90)% and (88.17±5.90)%,respectively, in aplastic anemia patients with PIG-A gene mutation;and (91.87±4.79)% and (94.24±3.76)%, respectively, in aplastic anemia patients with no PIG-A gene mutation. Both were significantly decreased(P<0.05)compared with (97.86±1.52)% and (98.82±1.42)%, respectively, in granulocytes of normal control group. CONCLUSION: The PIG-A gene mutations and decreased expressions of CD55 and CD59 in granulocytes may suggest clonal hematopoietic in patients with aplastic anemia.

Key words: aplastic anemia, PIG-A, exon, CD55, CD59