MULTIPLE KARYOTYPIC ABNORMALITIES IN 3 CASES OF SMALL-CELL VARIANT OFT-CELL PROLYMPHOCYTIC LEUKEMIA

Cytogenetic, clinical, and laboratory findings of three patients with a small cell variant of T-cell prolymphocytic leukemia (T-PLL) are pre sented. Immunophenotypic studies of the morphologically typical small cell variant prolymphocytes showed a mature helper T-cell phenotype (C D4(+) CD8(-)) in one patient and a common thymocyte phenotype (CD4(+) CD8(+)) in two other patients. The cytogenetic analysis revealed compl ex karyotypes with several structural aberrations in the peripheral bl ood lymphocytes of all three patients. In all cases chromosome 14 was affected with the breakpoint at 14q11. Inversion (14) and isochromosom e 8q, often reported as an additional aberration in T-PLL, were detect ed in two of the patients. In two patients a translocation of the shor t arm of chromosome 12 was also seen. The T-ceII receptor beta-chain g ene showed a clonal rearrangement in all three patients, whereas no re arrangements were detected in the immunoglobulin genes. The survival o f the patients ranged from 10 weeks to 48 months. The association betw een cytogenetic, clinical, and laboratory data is discussed.