Prognosis

The natural history of paroxysmal nocturnal haemoglobinuria (PNH) is not really known, probably because of its rarity. Further, the advent of specific treatment will probably alter the natural history of the disease.[28] Most studies in the US or Europe show a median post-diagnosis life-span of 10 to 15 years.[11][18][23] This may be longer in East Asian populations, as these populations have markedly less incidence of thrombosis, the worst prognostic complication seen among Europeans. Uncommonly, the PNH clone may spontaneously disappear.[11][18]

PNH in the setting of aplastic anaemia

The clinical course may be determined by the degree and responsiveness of aplastic anaemia. The incidence of thrombosis and overall survival among Western patients do not seem to be different if there is a prior history of aplastic anaemia.[15]

Subclinical PNH

Patients who present with subclinical PNH do not typically progress to clinical PNH. In 80% of cases where glycosylphosphatidylinositol-anchored proteins (GPI-AP)-deficient cells are detected in the setting of bone marrow failure, these cells make up <1% of total circulating granulocytes. These patients have no clinical or biochemical evidence of haemolysis and do not require specific treatment for PNH.[2]

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