阵发性睡眠性血红蛋白尿症患者血小板膜补体复合物沉积及其异常活化的研究

OBJECTIVE: To explore the expression levels of terminal complement complex (C5b-9) and CD62p on platelets and the soluble C5b-9 (sC5b-9) level in serum in patients with PNH or PNH-aplastic anemia (AA). METHODS: Serum levels of sC5b-9, complement C3 and C4 were detected by using ELISA in 25 patients with PNH/PNH-AA. The quantities of C5b-9 and CD62p on the membrane of platelets were detected by flow cytometry. RESULTS: ①In PNH/PNH-AA group, the serum sC5b-9 level [390.27 (265.73–676.87) µg/L] was lower than that in control group [540.39 (344.20–1 576.78) µg/L] (P< 0.01). ②The platelet PNH clone (CD59(−)CD61(+)/CD61(+)) size [50.58 (23.29–81.60)%] was bigger in the PNH/PNH-AA group than that [23.57 (15.58–29.02)%] in control group (P<0.01). The percentages of C5b-9 deposition (C5b-9(+)CD61(+)/CD61(+)) were higher on the PNH clone platelets (CD59(−)CD61 (+)) in the PNH/PNH-AA group [(17.53±6.27)%] than those on the normal platelets (CD59(+)CD61(+)) in PNH patients [(11.33±5.03)% ] and control [(10.88±3.58)% ] group (P<0.01). ③The expression of CD62p (CD62p(+) CD61(+)/CD61 (+)) on PNH clone platelets in PNH patients [(61.98±11.71)% ] was higher than that on the normal platelets in PNH patients [(43.76±11.30)% ] and control group [(38.23±18.07)% ] (P<0.01). In addition, the expression of CD62p on normal platelets was higher in PNH patients than control (P<0.05). ④The deposition of C5b-9 positively correlated with the expression of CD62p on the platelets (r=0.559, P=0.002). CONCLUSION: Deficiency of CD59 antigen on platelets in PNH patients may lead to the deposition of C5b-9 on its membrane and its dysfunction, which may contribute to thrombosis events in PNH.