Chronic lymphocytic leukemia and prolymphocytic leukemia: a clinicopathological reappraisal.

A series of 300 cases of chronic B-cell leukemia was studied in relation to clinical and laboratory features, and three groups were identified on the basis of the percentage of circulating prolymphocytes (%PROL): typical CLL less than or equal to 10% PROL, 174 cases; PLL greater than 55% PROL, 42 cases; and an intermediate group CLL/PL (11%-55% PROL), 84 cases. Some features of the CLL/PL group resemble those of PLL, such as a disproportionate splenomegaly in relation to the degree of lymphnode involvement. However, membrane markers suggested a closer affinity of CLL/PL with CLL [high percentage of M rosettes, expression of the P67 (T1) antigen, and low reactivity with the McAb FMC7], although high-density SmIg was found in one-third of CLL/PL, as well as in the majority of the PLL cases. Cells volume measurements demonstrated that the prolymphocytes of both PLL and CLL/PL are significantly larger than the homogeneous population of small lymphocytes of typical CLL. Followup studies of the PB picture in CLL and CLL/PL showed that the majority of patients maintain a relatively stable percentage of PROL, but a progressive prolymphocytoid transformation to a PLL-like disease may occur in some cases. On univariate analysis of survival, seven features of disease had a high prognostic values for the whole group of patients: %PROL, absolute number of PROL (ABS PROL), WBC, spleen size, M rosettes, SmIg intensity, and age. However, only ABS PROL (greater than 15 X 10(9)/l) and spleen size (greater than 8 cm) were shown to be independent prognostic features on a multivariate regression analysis. The median survival time of patients with PLL (3 years) was significantly shorter than the median of 8 years for patients with CLL. Within the heterogeneous CLL/PL group, patients with ABS PROL greater than 15 X 10(9)/l (two-thirds) had a median survival time as bad as for PLL patients, whereas the median has not been reached for those with ABS PROL less than 15 X 10(9)/l.