Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026986 (myelodysplastic syndrome)
 14,926 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Paroxysmal nocturnal haemoglobinuria (PNH) is an acquired haemolytic anaemia, clonal in nature, due to somatic mutation. PNH may evolve to aplastic anaemia; more rarely to a myelodysplastic syndrome (MDS) or to acute myeloid leukaemia (AML). We have studied a patient who suffered from PNH and later developed refractory anaemia with ringed sideroblasts (RARS) associated with trisomy 8. By testing peripheral blood cells with appropriate antibodies we have shown that all of the red cells, neutrophils and monocytes, as well as 20% of the lymphocytes, belonged to the PNH clone; in contrast, only 43% of neutrophils and 22% of monocytes belonged to the MDS clone. We infer that the MDS must have arisen from within the PNS clone.
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PMID:Myelodysplasia in a patient with pre-existing paroxysmal nocturnal haemoglobinuria: a clonal disease originating from within a clonal disease. 794 86

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hemolytic anemia in which abnormal red blood cells with enhanced susceptibility to complement undergo intravascular hemolysis when complement is activated in vivo, resulting in hemoglobinuria. This enhancement of complement susceptibility appears to involve multipotent stem cells and, in this respect, is thought to closely resemble myelodysplastic syndrome. Recently, it has been reported that the increased susceptibility of PNH cells to complement-mediated lysis is related to a deficiency of complement regulatory membrane proteins, especially CD55 and CD59. Both proteins are glycosylphosphatidylinositol (GPI)-anchored membrane proteins. It was found that a deficiency of GPI-anchored membrane proteins in PNH cells is due to the faulty synthesis of the GPI-anchor which may occur during early synthesis. Moreover, it is suggested that an abnormality of the PIG-A (phosphatidylinositol glycan-class A) gene, which is related to the early stage of GPI-anchor synthesis, is responsible for the pathogenesis of PNH. In conclusion, the clinical expression of PNH is dependent on two factors, complement susceptibility of PNH blood cells and changes in bone marrow function. The search for the ideal treatment of this disease may be aided by resolving the relationship between the two.
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PMID:Glycosylphosphatidylinositol (GPI)-anchored membrane proteins in clinical pathophysiology of paroxysmal nocturnal hemoglobinuria (PNH). 860 38

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.
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PMID:[Paroxysmal nocturnal hemoglobinuria: from physiopathology to treatment]. 2049 98

Erythrophagocytosis by neutrophils is a rare morphological phenomenon described in patients with clonal malignancies of haematopoiesis with myelodysplasia and in some haemolytic conditions including paroxysmal cold haemoglobinuria, haemolysis caused by snake-bite, sickle cell anaemia and other defects of red cells. We describe a female patient who presented with acquired haemolytic anaemia. Erythrophagocytosis was found in around 35% of neutrophils of the peripheral blood. A similar picture was seen in the bone marrow, but with additional erythrophagocytosis by macrophages. These two processes were considered as the main causes of anaemia, but the first one seemed to be predominant. Malignancies, autoimmunisation disorders and infections were excluded. Immunosuppressive therapy with corticosteroids was implemented, but had to be stopped because of side effects. Long-term normalization of peripheral blood morphology was achieved after splenectomy. Splenectomy may be considered a therapeutic option for patients with diagnosed neutrophil erythrophagocytic hyperactivity. Therapy with corticosteroids is also possible, but the long-term effects remain unknown.
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PMID:Erythrophagocytosis by neutrophils--a rare morphological phenomenon resulting in acquired haemolytic anaemia? 2141 43