L. Longo et al., MYELODYSPLASIA IN A PATIENT WITH PREEXISTING PAROXYSMAL-NOCTURNAL HEMOGLOBINURIA - A CLONAL DISEASE ORIGINATING FROM WITHIN A CLONAL DISEASE, British Journal of Haematology, 87(2), 1994, pp. 401-403
Paroxysmal nocturnal haemoglobinuria (PNH) is an acquired haemolytic a
naemia, clonal in nature, due to somatic mutation. PNH may evolve to a
plastic 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 siderobla
sts (RARS) associated with trisomy 8. By testing peripheral blood cell
s with appropriate antibodies we have shown that all of the red cells,
neutrophils and monocytes, as well as 20% of the lymphocytes, belonge
d to the PNH clone; in contrast, only 43% of neutrophils and 22% of mo
nocytes belonged to the MDS clone. We infer that the MDS must have ari
sen from within the PNS clone.