Abstract
Forty-one patients diagnosed as having B-cell chronic lymphocytic leukemia in Japan were evaluated. Patients were classified into five groups (CLL, CLL-L, CLL/PL, PLL, LSCL) according to differential counts of small lymphocytes, large lymphocytes, prolymphocytes, immunoblasts and/or lymphosarcoma cells among the lymphoid cells in the first available peripheral smears based on Melo's morphological criteria. Patients with typical CLL, difined as having more that 90% small lymphocytes, were seven (17%) of 41 patients.
Phenotypical characteristic of CLL and its subgroups in Japan was considered to be the high expression of activated antigens, such as CD22, PCA1 and CD25. This finding may support the relatively higher proportion of atypical CLL with high percentage of large lymphocytes or prolymphocytes in Japan than that in Western countries. The molecular biological analysis revealed the deletion of Cμ gene in one allele in three sIg-negative cases. The incidence of CLL, CLL-L and CLL/PL in Japan was deduced to be 1/10 of that in Western countries.
