Pb2050: comparison of clinical characteristics of child and adult patients with pnh: ——ten-year follow-up

Topic: 12. Bone marrow failure syndromes incl. PNH - Clinical Background: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired clonal hematopoietic stem cell disease, characterized by intravascular hemolytic anemia, thrombophilia and bone marrow failure. Compared with adults, PNH is less likely to occur in children. Aims: The study aimed to clarify the demographic and clinical characteristics of children with PNH compared with adults. Methods: This study retrospectively compared the demographic features, PNH classification and thrombotic events of 23 child and 67 adult PNH patients, and evaluated the blood and hemolytic indexes, organ function status and survival. This retrospective study was conducted by the Chinese Eastern Collaboration Group of Anemia (ChiCTR2100050945) from May 2014 to July 2020, including five centers: the First Affiliated Hospital with Nanjing Medical University (Nanjing, China), Affiliated Hospital of Jiangnan University (Wuxi, China), Nanjing Jiangning Hospital (Nanjing, China), the Second Hospital of Nanjing (Nanjing, China) and the Second Hospital of Anhui Medical University (Hefei, China). Results: The two groups didn’t show differences in gender (p=0.817) and PNH classification (p=0.238), including classic PNH (56.52% vs 71.64%, p=0.181), PNH combined bone marrow disease (BMD) (34.78% vs 25.37%, p=0.385), or subclinical PNH (8.70% vs 2.99%, p=0.269) (Table 1). Thrombosis events (13.04% vs 8.96%, p=0.688), D-dimer level (0.34mg/L vs 0.39mg/L, p=0.963), reticulocyte percentage (4.65% vs 5.14%, p=0.089), hemoglobin level (66 g/L vs 72 g/L, p=0.601), neutrophil count (2×109/L vs 2.06×109/L, p=0.978), platelet count (95×109/L vs 104 ×109/L, p=0.526), lactate dehydrogenase level (790 U/L vs 1010 U/L, p=0.407), and indirect bilirubin level (12μmol/L vs 18.2μmol/L, p=0.177) were comparable in two groups (Table 1). The proportion of patients in hemolytic state (LDH＞1.5×ULN) was also similar (p=0.241). Creatinine level and PNH clone size in children group were lower than those in adult group (47.9 μmol/L vs 61 μmol/L, p=0.031) (63.3% vs 86.9%, p=0.023). None with pulmonary hypertension was found in PNH children group, while 8 cases in adult group had mild pulmonary hypertension (p=0.009). The survival rate of PNH patients in children and adults were similar during the 10-year follow-up (92.9% vs 92.6%，P=0.968). Summary/Conclusion: Our study demonstrated PNH patients in children and adults both experienced similar clinical characteristics of hemolysis, thrombosis and cytopenia, but adult patients had larger PNH clone, higher creatinine levels and percentage of pulmonary hypertension.Keywords: Pulmonary hypertension, Children, Adult, Paroxysmal nocturnal hemoglobinuria (PNH)