CYTOGENETIC ABNORMALITIES IN 3 PATIENTS WITH B-CELL PROLYMPHOCYTIC LEUKEMIA

We present the cytological features, conventional cytogenetics, and in situ hybridization (ISH) findings of three cases of B-cell prolymphoc ytic leukemia (B-PLL). The diagnosis was made according to the French- American-British (FAB) criteria. We considered a diagnosis of B-PLL wh en a predominance (>50%1 of lymphoid cells with coarse chromatin but p rominent central nucleoli and more abundant cytoplasm than typical chr onic lymphocytic leukemia (CLL) cells were present. B-PLL express stro ng SIg, B-cell antigens, and reactivity with the monoclonal antibody F MC7. Chromosome analysis was carried out on lymphoid cells from periph eral blood and, in one patient, from lymph node. The phytohemagglutini n (PHA) mitogen was used. ISH was performed with two types of probes: the biotin-labeled chromosome 12-specific alpha satellite DNA probe to detect trisomy 12, and biotin labeled libraries of whole chromosomes 1, 7, and 14. Clonal chromosome abnormalities were found in all three patients; in one, a complex karyotype was observed. The most frequent recurrent abnormality was trisomy 12. Our results suggest that PLL usu ally presents with cytogenetic abnormalities. The finding of transloca tion (11;14) is noteworthy; chromosomes 1 and 3 are also involved. (C) Elsevier Science Inc., 1998.