ACUTE-LEUKEMIA IN PAROXYSMAL-NOCTURNAL HEMOGLOBINURIA - CASE-REPORT AND REVIEW OF THE LITERATURE

Paroxysmal nocturnal haemoglobinuria (PNH) terminating in acute leukae mia (AL) is an infrequent condition. In several cases, flow cytometric analysis of glycosylphosphatidylinositol anchored membrane proteins s uch as DAF and CD59/MACIF has suggested the leukaemic cells to be deri ved from the PNH clone, thereby implicating PNH as a potential preleuk aemic disease. In the present paper, we review the data for one patien t treated in our hospital and 20 cases reported in the literature from 1969 to 1993. The sex ratio is 1 female/2 males, mean age at diagnosi s of PNH was 46 years and the mean interval between the diagnoses of P NH and ALwas 53 months. AL type was AML M6 in 8 patients, other types of AML in 12 and ALL in one, with a mean survival of 7.1 months follow ing diagnosis of AL. In all cases analyzed, the PNH phenotype of eryth rocytes disappeared with progression of AL, whereas reappearance of th is phenotype with complete remission of AL was inconstant. PNH would t hus appear to be a potential preleukemic disease. When this disorder t erminates in AL, the type is often AML M6, although ALL is also possib le. The prognosis of AL in PNH is poor as for other secondary leukaemi as. Apart from marrow aplasia, leukaemic transformation is another lif e threatening complication of PNH which may justify allogeneic bone ma rrow transplantation (allo-BMT) and potential leukaemic transformation can therefore be an additional argument in favour of allo-BMT when pa ncytopenia develops in PNH patients.