Analysis of baseline characteristics, disease burden and long-term follow-up of 167 patients with Paroxysmal Nocturnal Hemoglobinuria at a single center in Brazil.

Paroxysmal nocturnal hemoglobinuria (PNH) can occur as a hemolytic form or small PNH clone found in a patient with bone marrow failure.
Methods: Describe Brazilian retrospective PNH cohort and identify the impact of disease burden on long-term follow-up.
Results: 167 patients, mean age at diagnosis 28.4 (7.1-71.2 years), four years mean interval between onset of cytopenia/aplasia diagnosis and PNH clone detection. Patients were divided into 15 Classic PNH, 55 Hemolytic PNH with bone marrow hypoplasia (PNH/AA), and 97 Subclinical PNH (sc-PNH). Hypocellular bone marrow was found in 89.2%; 55 had hemoglobinuria and 22 thrombosis during monitoring. WBC PNH clone correlated with RBC PNH clone, LDH and cytopenia. Subclinical patients had lower median lower RBC clone (2.0% vs 24.0% vs 57.8%) and WBC clone (11.7% vs 58.8% vs 81.2%) than PNH/AA and Classic PNH, respectively. PNH granulocyte clone was 89.1% in thrombotic patients. Ten-year overall survival 80.4% and mortality in transplanted patients 9.6%. Sepsis was mortality cause in subclinical PNH (16/18, 88.8%), and thrombosis in hemolytic PNH (11/13, 84.6%).
Conclusion: Large PNH clones and LDH burden were associated with increased hemolysis and thrombosis risks, while young patients were associated with small PNH clones and subclinical form of the disease. Knowledge of the patient profile, the low risk associated with HSCT, and the use of long-term IST may be instrumental in the clinical management of PNH in restricted-resources countries.
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