Study of Anticoagulant, Procoagulant, and Fibrinolytic Pathways in Mexican Patients With Paroxysmal Nocturnal Hemoglobinuria.

BACKGROUND: In Mexico, the frequency of thromboembolic events associated to paroxysmal nocturnal hemoglobinuria is 3%; a clone size > 50% in granulocytes has been associated with a higher risk of thromboembolic events. METHODS: Between 2001 and 2012, 40 patients with paroxysmal nocturnal hemoglobinuria were studied. In 12 cases anticoagulant, procoagulant, and fibrinolytic pathways were analyzed. RESULTS: Only two of 40 patients (5%) developed a thromboembolic event over a 25.5-year follow-up period. From 12 patients, 91.7% had a paroxysmal nocturnal hemoglobinuria clone > 50% in granulocytes and 83.3% a clone > 50 % in monocytes. Five of 12 cases had elevated FV levels and four showed increased FVIII, von Willebrand factor antigen, von Willebrand factor ristocetin cofactor activity and FX. Protein S and protein C were decreased in nine and three patients, respectively. Only antithrombin correlated positively with paroxysmal nocturnal hemoglobinuria clone size in monocytes (p = 0.0442), whereas von Willebrand factor ristocetin cofactor correlated negatively with lactic dehydrogenase levels (p = 0.0186). No statistically significant associations were recorded with all other factors. CONCLUSION: The low frequency of thromboembolic events in Mexican patients could partly be explained by the associations between anticoagulant system (antithrombin) with paroxysmal nocturnal hemoglobinuria monocyte clone size, and procoagulant system (von Willebrand factor ristocetin cofactor) with lactic dehydrogenase levels.

[Paroxysmal nocturnal hemoglobinuria: from physiopathology to treatment]. / Hemoglobinúria paroxística noturna: da fisiopatologia ao tratamento.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disorder, an acquired chronic hemolytic anemia, often associated with recurrent nocturnal exacerbations, recurrent infections, neutropenia, thrombocytopenia, and episodes of venous thrombosis. Its clinical course is highly variable. It frequently arises in association with bone marrow failure, particularly aplastic anemia and myelodysplastic syndrome. It is also an acquired thrombophilia, presenting with a variety of venous thrombosis, mainly manifested with intra-abdominal thrombosis, here the major cause of mortality. The triad of hemolytic anemia, pancytopenia, and thrombosis makes a truly unique clinical syndrome of PNH, which was reclassified from a purely acquired hemolytic anemia to a hematopoietic stem cell mutation defect of the phosphatidyl inositol glycanclass-A gene. This mutation results in an early block in the synthesis of glycosylphosphatidylinositol (GPI) anchors, responsible for binding membrane functional proteins. Among these proteins are the complement inhibitors, especially CD55 and CD59, that play a key role in protecting blood cells from complement cascade attack. Therefore, in PNH occurs an increased susceptibility of red cells to complement, and consequently, hemolysis. We here review PNH physiopathology, clinical course, and treatment options, especially eculizumab, a humanized monoclonal antibody that blocks the activation of terminal complement at C5 and prevents formation of the terminal complement complex, the first effective drug therapy for PNH.

Hemoglobinúria paroxística noturna: da fisiopatologia ao tratamento / Paroxysmal nocturnal hemoglobinuria: from physiopathology to treatment

Hemoglobinúria paroxística noturna (HPN) é uma anemia hemolítica crônica adquirida rara, de curso clínico extremamente variável. Apresenta-se frequentemente com infecções recorrentes, neutropenia e trombocitopenia, e surge em associação com outras doenças hematológicas, especialmente com síndromes de falência medular, como anemia aplásica e síndrome mielodisplásica. É considerada ainda um tipo de trombofilia adquirida, apresentando-se com tromboses venosas variadas, com especial predileção por trombose de veias hepáticas e intra-abdominais, sua maior causa de mortalidade. A tríade anemia hemolítica, pancitopenia e trombose faz da HPN uma síndrome clínica única, que deixou de ser encarada como simples anemia hemolítica adquirida para ser considerada um defeito mutacional clonal da célula-tronco hematopoética (CTH). A mutação ocorre no gene da fosfaditilinositolglicana classe-A, e resulta no bloqueio precoce da síntese de âncoras de glicosilfosfaditilinositol (GPI), responsáveis por manter aderidas à membrana plasmática dezenas de proteínas com funções específicas. A falência em sintetizar GPI madura gera redução de todas as proteínas de superfície normalmente ancoradas por ela. Dentre elas estão o CD55 e o CD59, que controlam a ativação da cascata do complemento. Assim, na HPN há aumento da susceptibilidade de eritrócitos ao complemento, gerando hemólise. Revisa-se aqui sua fisiopatologia, curso clínico, os tratamentos disponíveis com ênfase para o transplante de células-tronco hematopoéticas alogênicas e para o eculizumab, um anticorpo monoclonal humanizado que bloqueia a ativação do complemento terminal no nível C5 e previne a formação do complexo de ataque à membrana, a primeira droga a demonstrar eficácia no tratamento da HPN.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disorder, an acquired chronic hemolytic anemia, often associated with recurrent nocturnal exacerbations, recurrent infections, neutropenia, thrombocytopenia, and episodes of venous thrombosis. Its clinical course is highly variable. It frequently arises in association with bone marrow failure, particularly aplastic anemia and myelodysplastic syndrome. It is also an acquired thrombophilia, presenting with a variety of venous thrombosis, mainly manifested with intra-abdominal thrombosis, here the major cause of mortality. The triad of hemolytic anemia, pancytopenia, and thrombosis makes a truly unique clinical syndrome of PNH, which was reclassified from a purely acquired hemolytic anemia to a hematopoietic stem cell mutation defect of the phosphatidyl inositol glycanclass-A gene. This mutation results in an early block in the synthesis of glycosylphosphatidylinositol (GPI) anchors, responsible for binding membrane functional proteins. Among these proteins are the complement inhibitors, especially CD55 and CD59, that play a key role in protecting blood cells from complement cascade attack. Therefore, in PNH occurs an increased susceptibility of red cells to complement, and consequently, hemolysis. We here review PNH physiopathology, clinical course, and treatment options, especially eculizumab, a humanized monoclonal antibody that blocks the activation of terminal complement at C5 and prevents formation of the terminal complement complex, the first effective drug therapy for PNH.

Hemoglobinuria Paroxística Nocturna: apuntaciones sobre su historia / Paroxysmal Nocturnal Hemoglobinuria: notes on its history

La hemoglobinuria Paroxística Nocturna (HPN) fue descrita inicialmente por William Gull en 1866, en Londres Inglaterra y representa desde su descripción inicial un buen ejemplo de la evolución de los conceptos y conocimientos, en función del tiempo, en torno a una enfermedad. A William Gull le corresponde el mérito de haber descrito que el pigmento excretado en orina no correspondía a glóbulos rojos (GR). En 1882 Paul Strübing comunicó la siguiente descripción de la HPN. Strübing describió la asociación entre la hemoglobinuria y el ejercicio físico; propuso que la anormalidad residía en los GR, que al circular por los riñones sufrían hemólisis y describió la asociación entre la administración de hierro y las crisis de hemólisis. El nombre de HPN fue establecido en 1928 por Enneking. En 1911, Hijmans-van den Berg demostró que la acidificación de sueros normales o de pacientes con HPN, inducía lisis en los GR de pacientes con HPN. Sin embargo las observaciones de Thomas Hale Ham en 1937, que le permitieron proponer que el defecto de los GR en la HPN consistía en una mayor susceptibilidad a la lisis por el complemento (C'). Pangburn y col. y el grupo de Nicholson-Weller en 1983, describieron que en la HPN existe disminución cuantitativa del factor que acelera la degradación de las convertasas del C' fijadas a la membrana (DAF = "decay accelerating factor", o CD55). En 1987 y 1988, Zalman y col. y Blaas y cols., respectivamente, describen la deficiencia en esta células de la proteina reguladora de la fracción C-59, el inhibidor de membrana de la lisis reactiva o CD59. En 1992, Mahoney y col. y Hirose y su grupo demostraron que en la HPN la síntesis del glucosilfosfatidil inositol (PIG) era defectuosa, lo que en su turno impedía se anclaran las proteinas antes descritas. Estudios realizados por Takeda y col., en la Universidad de Osaka Japón, y publicados en 1993 permitieron clonar el gen PIG (gen PIG-A) e identificaron en la HPN una mutación somática que ocasionaba la pérdida de la función del gen PIG-A. En la actualidad se postula que la clona de HPN emerge como defensa a algún factor externo o interno que inhiba la hematopoyesis normal, pero incapaz de inhibir las células hematopoyéticas deficientes en las protéinas ancladas en el PIG

Hemoglobinúria paroxística noturna na gestação / Paroxysmal noctural hemoglobinuria: a case report

Hemoglobinúria Paroxística Noturna (HPN) é uma doença resultante da alteração clonal da célula tronco da medula óssea, que se manifesta por episódios de hemólise intravascular, seguida de hemoglobinúria. A gestação é relatada como fator desencadeante dos episódios hemolíticos. Relata-se um caso de paciente branca, 35 anos, portadora de HPN há 11 anos que, no decorrer da terceira gestação, necessitou realizar repetidas transfusões de hemácias lavadas. Cêrca de um mês após o parto retornou à emergência do hospital, em estado toxêmico. Transferida para a UTI, apresentou acidente vascular encefálico, evoluindo para óbito

[Paroxysmal nocturnal hemoglobinuria: physiopathology and therapeutic management]. / Hemoglobinuria paroxística nocturna: fisiopatología y manejo terapéutico.

The authors study the pathophysiology and the therapy of patients with paroxysmal nocturnal hemoglobinuria according with the literature reviewed. They also refer to have studied seven cases with HPN, two of which were women and five men, between the ages of 26 and 76 years of age, with symptomatology that varied from moderate, chronic hemolytic anemia and acholuria, to severe pancytopenia with bleeding, infections, and requiring transfusions, antibiotics, corticosteroids, androgens and other supportive measures. Most of them had enlargement of the spleen and liver, especially during hemolytic crises.

Hemoglobinuria paroxística nocturna: fisiopatalogía y manejo terapéutico / Hemoglobinuria paroxysmal nocturnal: physioapathology and therapeutics handling

Se hace la revisión de la fisiopatología y el manejo terapéutico de los pacientes con hemoglobinuria paroxística nocturna (HPN), de acuerdo con la información bibliográfica que se menciona; y se refiere al hallazgo de siete casos, dos mujeres y cinco hombres, entre 26 y 76 años de edad, con HPN y sintomatología que iba desde moderada anemia hemolítica crónica y orina acolúrica, hasta severa pancitopenia, con sangramientos, infecciones y requerimiento de transfusiones, antibióticos, corticoides, andrógenos y otras medidas de soporte. La mayoría presentó agrandamiento del bazo y del hígado, especialmente durante las crisis hemolíticas