Significance of paroxysmal nocturnal hemoglobinuria clone in immunosuppressive therapy for children with severe aplastic anemia.

Objectives: To study the association between paroxysmal nocturnal hemoglobinuria (PNH) clone and immunosuppressive therapy (IST) in children with severe aplastic anemia (SAA).

Methods: A retrospective analysis was performed on the medical data of 151 children with SAA who were admitted and received IST from January 2012 to May 2020. According to the status of PNH clone, these children were divided into a negative PNH clone group (=135) and a positive PNH clone group (=16). Propensity score matching was used to balance the confounding factors, and the impact of PNH clone on the therapeutic effect of IST was analyzed.

Results: The children with positive PNH clone accounted for 10.6% (16/151), and the median granulocyte clone size was 1.8%. The children with positive PNH clone had an older age and a higher reticulocyte count at diagnosis (<0.05). After propensity score matching, there were no significant differences in baseline features between the negative PNH clone and positive PNH clone groups (>0.05). The positive PNH clone group had a significantly lower overall response rate than the negative PNH clone group at 6, 12, and 24 months after IST (<0.05). The evolution of PNH clone was heterogeneous after IST, and the children with PNH clone showed an increase in the 3-year cumulative incidence rate of aplastic anemia-PNH syndrome (<0.05).

Conclusions: SAA children with positive PNH clone at diagnosis tend to have poor response to IST and are more likely to develop aplastic anemia-PNH syndrome.