Patients who have a positive pretreatment paroxysmal nocturnal hemoglobinuria (PNH) clone have better hematological responses to intensive immunosuppressive therapy (IIST) compared with patients who did not, according to a study published in Hematology. 

Aplastic anemia and PNH have many overlapping features. Studies suggest that the cause of PNH clones associated with aplastic anemia is hematopoietic stem cells/progenitor cells. Current evidence regarding the prognostic value of the presence of a pretreatment PNH clone in the use of IIST is lacking. The authors of the study thus sought to further investigate this issue. 

The research team conducted a literature review using international academic search engines. They also used 4 Chinese databases to extract relevant studies from inception until September 2022. The research team obtained information from studies on aplastic anemia, patients who were tested for a PNH clone pretreatment (with the results being positive or negative), and comparisons of PNH-positive and -negative groups in terms of their response to IIST.  

Fifteen studies were included in the final analysis. Researchers reported that 8 studies highlighted hematological efficiency in aplastic anemia patients with a pretreatment PNH clone who were treated with IIST for 6 months. This difference was further apparent when comparing PNH-positive and -negative groups. The pooled odds ratio for the quality of hematological response was significant enough for the research team to conclude that the presence of a PNH clone leads to better outcomes when treated with IIST. 

Read more about PNH etiology 

There were some limitations with the study. First, only 1 prospective study was analyzed; second, aplastic anemia is a rare disease and hence only a small number of participants were included in the study (2 of the studies reviewed had a sample size fewer than 40 participants). 

“In conclusion, our study found that the presence of a pre-treatment PNH clone has a positive effect on the hematological response after IIST,” the authors wrote. 


Li J, Li X, Cai L, et al. Prognostic value of pre-treatment PNH clone among the patients with aplastic anemia: a meta-analysisHematology. Published online May 16, 2023. doi:10.1080/16078454.2023.2204617