OBJECTIVETo explore the pathogenesis of abnormal WT1 expression in paroxysmal nocturnal hemoglobinuria (PNH).

METHODSThe expression of WT1 mRNA in CD59⁻ and CD59⁺ bone marrow mononuclear cells (BMMNC) were measured by semi-quantitative reverse transcription PCR. After WT1 gene silence by RNA interference (RNAi) technology, biological characteristics of BMMNC were investigated by flow cytometry.

RESULTSThe relative expression of WT1 mRNA in PNH CD59⁻ BMMNC (1.06 ± 0.12) was significantly higher than that in PNH CD59⁺ BMMNC (0.90 ± 0.12) and normal BMMNC (0.86 ± 0.05, P<0.05), but there was no significant difference between PNH CD59⁺ BMMNC and normal BMMNC (P>0.05). WT1 mRNA expression in PNH was positively correlated with the proportion of CD59⁻ cells (r²=0.490, P=0.016), but had no relationship with the proportion of CD59⁺ cells. After WT1 gene silence by siRNA in PNH CD59⁻ BMMNC, WT1 mRNA expression was decreased. The proportions of G0/G1 phase in PNH CD59⁻ cell blank control group and siRNA-scr transfected group were (92.73 ± 3.71)% and (93.06 ± 4.14)%, and the proportions of S phase were (6.99 ± 3.61)% and (6.73 ± 4.08)%, respectively. The proportions of G0/G1 and S phase in siRNA-WT1 transfected group was (94.46 ± 3.71)% and (5.40 ± 3.55)%, respectively. There were significant differences in the proportions of G0/G1 phase and S phase among the controls, siRNA-WT1 transfected group and siRNA-scr transfected group (P<0.05). The rate of apoptosis in siRNA-WT1 transfected group [(35.91 ± 22.36)%] was significantly higher than those in controls [(26.12 ± 17.10)%] and siRNA-scr transfected group [(27.39 ± 18.99)%] (P<0.05).

CONCLUSIONsiRNA-WT1 could effectively suppress the WT1 gene expression of CD59⁻ clone in PNH patients, inhibit its proliferation, and promote its apoptosis. WT1 gene expression might contribute to PNH clone proliferation.