[The variation and clinical significance of paroxysmal nocturnal hemoglobinuria clone in patients with aplastic anemia before and after immunosuppressive therapy].

Objective: To evaluate the evolution of paroxysmal nocturnal hemoglobinuria (PNH) clone and its clinical significance before and after immunosuppressive therapy (IST) in patients with aplastic anemia (AA).

Methods: A total of 186 patients diagnosed as AA were enrolled in this study. Among them, 55 patients were diagnosed as severe AA (SAA) and treated with cyclosporine (CsA) plus anti-thymocyte globulin (ATG), 131 were diagnosed as non SAA (NSAA) and treated with CsA alone. All patients were screened for PNH clone by flow cytometry before treatment and followed up for 18-76 months, with a median time of 22 months.

Results: Positive PNH clones were detected in 10 SAA (18.9%) patients, significantly more than that of NSAA group [9 patients (7.4%), t = 5.041, P = 0.025]. The proportions of PNH clones in SAA group at 6, 12, 24 and > 24 months were 13.38%, 14.88%, 20.00% and 18.85%, respectively, also significantly higher than those of NSAA patients (5.67%, 5.31%, 5.47% and 9.08%, all P values < 0.05). Clinical response rates were comparable in both ATG+CsA or CsA alone groups no matter PNH clone was positive or negative.

Conclusions: PNH clone are detectable in AA patients either treated with ATG plus CsA or CsA alone, and more significant by ATG plus CsA. Whether PNH clone occurred before or after IST does not affect the therapeutic efficacy.