Paroxysmal Nocturnal Hemoglobinuria (PNH): Long Term Follow up of 48 Patients in a Single Institution.

Background: PNH is a clonal acquired disease characterized by poor expression of CD55 and CD59, adding higher lytic activity to the complement pathway, ending up in hemolysis, pancytopenia and thrombosis. The clinical variability and the lack of effective therapeutics make the treatment of PNH a real challenge. Material and methods: A retrospective analysis of 48 patients diagnosed with PNH between feb/1997 and march/2006 admitted to our center was performed. Before 1999, diagnosis was made by HAM and SACAROSIS tests. From this point immunophenotyping analysis was used to establish diagnosis. Bone marrow aspirate and biopsy, cytogenetic and biochemistry analysis were performed for exclusion of comorbities. Patients were divided in two groups: 1) de novo PNH associated with marrow failure (MF) and 2) PNH as an evolution of severe aplastic anemia (SAA) or mielodysplastic syndrome (MDS). Response was defined as reduction at hemolytic episodes as well as improvement of CBC and transfusion requirements. Results: Median age was 24 years (range 9–75); male patients constituted 58% of the sample (male/female: 1,4:1). De novo PNH with associated marrow failure occurred in 22 patients (group 1) and evolutive PNH in 15, being 13 from previous SAA and 2 from previous hypoplastic MDS (group 2). Thirty seven patients were followed at our clinic during this time: 25 (67,5%) received immunesupression with cyclosporine and steroids. Overall response (partial or complete) after one year of therapy was 84% (31/37). The remaining 11 patients (32,5%) received steroids alone, androgens or only observation, four of them remained with stable disease. HLA match hematopoietic stem cell transplantation (HSCT) was performed in 18/48 (38%), being 11 from group 1 and 7 from group 2. Main indications were: pancytopenia (77%), thrombosis (17%) and AML (6%). Only nine patients died (19%): five after HSCT and 4 of those followed at our clinic (massive thrombosis and hemolysis). Overall survival after HSCT was 72% with median follow-up of 890 days. Overall survival among outpatient clinic patients was 86% with a median follow-up of 2340 days. Most frequent outpatient events were: hemolysis (48%), pancytopenia (13%), thrombosis (13 %), renal failure (9%) and infection (8%).Fourteen patients (37%) remained without symptoms. Conclusions: Immunosuppressive therapy with cyclosporine and corticosteroids is an excellent strategy in patients with PNH and associated marrow failure, leading to durable clinical responses. The present data supports previous published indications for HSCT: ASS and thrombosis. Overall survival of PNH patients who received HSCT achieved 72%.