Erythrokinetic studies in hairy-cell leukaemia.

Erythrokinetics were studied in 29 patients with hairy-cell leukaemia. In all cases there was an increase in plasma volume, closely correlated to the size of the spleen, indicating that the true degree of anaemia can only be appreciated by red cell volume measurement. Moderately increased haemolysis was observed in most cases, which did not correlate with the spleen size. Simultaneous study of autologous and isologous red cell life-span suggested an extra-corpuscular mechanism for the haemolysis in most patients. A quantitative erythropoietic defect, either relative or absolute, was found in half the cases, without any qualitative defect. Only one case showed erythroid metaplasia of the spleen. Thus marrow failure appears to be largely responsible for the anaemia and granulocytopenia in hairy-cell leukaemia. A clear correlation was shown between the short-term prognosis after splenectomy and the degree of hypersplenism. However, long-term survival correlated chiefly with the degree of bone marrow failure, whether splenectomy had been carried out or not. The results indicate that isotope studies in hairy-cell leukaemia are useful both in determining the best form of treatment and predicting survival.