A comparative study of the effectiveness of different mitogens for karyotypic analysis in chronic B cell leukemia

Clonal chromosome abnormalities in chronic lymphocytic leukemia patients revealed by TPA stimulation of whole blood cultures

Cells from 52 patients with chronic lymphocytic leukemia and two patients with prolymphocytic leukemia were stimulated in whole blood or bone marrow culture with the polyclonal B-cell mitogen tetradecanoyl phorbol acetate (TPA). Stimulation was successful in 50 of the 54 cases. Comparison with Epstein-Barr virus and pokeweed mitogen showed them to be much less successful mitogens under the conditions used. Twenty-one patients (39%) were found to have clonal abnormalities that were probably disease-related. The most common abnormality was trisomy 12 (five patients). Four patients had a deletion of the long arm of chromosome #11 and one patient had a t(11;14). Five patients had abnormalities of the long arm of chromosome #13, with four probably having breaks in band q14. Two patients were seen with trisomy 3 as the only abnormality. Overall, the results were similar to those of other groups, which shows that considerable karyotypic information can be obtained from the use of a single mitogen on a large series of chronic lymphocytic leukemia patients.

Prognostic significance of chromosome abnormalities in chronic lymphocytic leukaemia

Lymphocytes from 33 out of 63 patients with B-cell chronic lymphocytic leukaemia (B-CLL) were successfully stimulated for cytogenetic analysis by means of two B-cell mitogens: pokeweed mitogen and lipopolysaccharide-B, used after pretreatment of the cells with neuraminidase and galactose oxidase. All patients had abnormal clones in 30-100% of the cells analysed. Chromosomes more frequently involved were Nos. 1, 3, 6, 11, 12, 13 and 14. The most common abnormality was a marker 14q+ (breakpoint 14q32) seen in 17 cases; trisomy 12 was observed in seven cases. A clinical scoring system was used to investigate the correlation of chromosome abnormalities with prognosis. The group with 14q+ was often associated with features of progressive disease, namely; prolymphocytoid or Richter transformation, refractoriness to therapy, high WBC and advanced staging. A significant difference in survival was observed between patients with 14q+ and the rest: median survival from diagnosis being 45 months and over 64 months, respectively (P less than 0.05); when survival was calculated from the time of chromosome analysis the values were 8 months and more than 41 months, respectively (P less than 0.01). It is suggested that 14q+ is acquired during the evolution of CLL and that this development may be a key event in the clinical progression of B-CLL. Other abnormalities, including trisomy 12, were not found to be associated with a worse prognosis.

Isochromosome 17q in cell lines of two cases of B cell chronic lymphocytic leukemia

The cytogenetic study of lymphocytes stimulated by EB virus in two cases of B-CLL revealed an isochromosome 17q. This abnormality, well known in CML during the stage of blastic transformation, may not be specific to myeloid proliferation as it is also observed in malignant lymphomas and B- or T-CLL. The anomaly does not appear to have the same prognostic nature as in CML.

Karyotype analysis of B-lymphocytes transformed by Epstein-Barr virus in 21 patients with B cell chronic lymphocytic leukemia

The karyotypes of 21 patients with chronic B cell leukemia were studied using lymphoblastoid cell lines obtained with the aid of the Epstein-Barr virus. Ten patients had a normal karyotype and eleven patients, an abnormal. There is no single characteristic anomaly, but certain types were more frequent, i.e., 14q+ as a result of a translocation 11;14, trisomy 12, and an isochromosome 17q. Abnormalities in these same three chromosomes have been found in other hematologic malignancies. It is postulated that loci with control cell proliferation are present on chromosomes 12, 14, and 17.