Paroxysmal nocturnal hemoglobinuria in México: a 30-year, single institution experience

BACKGROUND: Paroxysmal nocturnal hemoglobinuria (PNH) stems from chronic, complement-mediated, intravascular hemolysis, which results in anemia, hemoglobinuria, fatigue, and other hemolysis-related disabling symptoms. Novel diagnostic methods have led into an increased identification of the disease. AIMS: To analyze the salient features of patients with PNH identified in a single institution in Mexico, in a 30-year period. MATERIAL AND METHODS: The records of 31 patients with PNH identified between 1984 and 2013 were reviewed; 20 females. Median age was 39 years, range 5 to 88. Patients were followed for periods of 0.5 to 221 months, median 46 months. RESULTS: Most patients (97%) presented peripheral blood cytopenias, 11 (35%) presented a thrombotic episode, whereas 4 (13%) showed hemolytic anemia. No thrombotic episode was fatal. In the cytopenic group, 4 patients with hemolysis were included and in the patients with the hemolytic variant the red blood cell destruction process was continuous while not paroxysmal. Anemia was recorded in 30 individuals; median hemoglobin levels were 8.5 g/dL, range 3.7 to 12.8. Leukopenia was present in 18 individuals; median white blood cell count was 3.3 x 109/L, range 1.6 to 10.8, whereas thrombocytopenia was present in 18 subjects; median platelet count was 67 x 109/L, range 6 to 546. Pancytopenia was present in 15 patients. Hemoglobinuria was recorded in 12 patients and low free haptoglobin levels coupled with increased lactic dehydrogenase levels, consonant with hemolysis in 4 patients. CONCLUSIONS: In Mexico the cytopenic variants are considerably more common than either the hemolytic or the thrombotic variants of the disease, this being particularly relevant since only the hemolytic variants of PNH are the ones which show a good response to the complement-blocking therapy employed nowadays in the treatment of the disease.