Clinical features and prognostic factors of Asian patients with paroxysmal nocturnal hemoglobinuria: results from a single center in China

Although all patients with paroxysmal nocturnal hemoglobinuria (PNH) have acquired mutations in the phosphatidylinositol glycan class-A(PIG-A)gene, their clinical courses are highly variable. We reviewed 280 PNH cases referred to our hospital from January 1990 through June 2010 to assess clinical presentations, prognostic factors influencing survival, difference among subcategories, and clinical significance of PNH clone size. The overall survival at 10 years after diagnosis estimated by Kaplan-Meier was 77.6%. Both univariate and multivariate analyses identified risk factors affecting survival, including age > 40 years, absolute neutrophil count < 0.5 x 10(9) cells/L, development of thrombotic events, evolution to myelodysplastic syndrome or acute myelogenous leukemia, and recurrent infections. The cohort of patients were divided into subcategories of classic PNH, PNH/AA, and PNH-sc/AA based on the recent proposed PNH working clinical classification, hemoglobinuria as the initial symptomatic manifestation was high up to 82.0% in classic PNH subcategory, whereas only as low as 1.4% in PNH-sc/AA subcategory; the frequencies of infectious (26.0%) and bleeding symptoms (14.0%) in classic PNH subcategory were significantly less than those in PNH/AA (25.3% and 51.7%, respectively) and PNH-sc/AA (48.3% and 83.2%, respectively) subcategories. Our results revealed that large PNH clone was associated with increased risks for hemoglobinuria and thrombosis, whereas small PNH clone was associated with bone marrow failure. Thus, this study may shed insights into Chinese PNH patients to set up individually therapeutic regimens.