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

In order best to study the karyotypic abnormalities of nine patients with chronic lymphocytic leukemia of B cell origin, we used a combination of T and/or B cell mitogens so as to achieve an optimal proliferative response. As assessed by DNA synthesis, and subsequent cytogenetic study, pokeweed mitogen (PWM) and protein A Sepharose (PROT A) appeared to hold promise as potent stimulators of neoplastic B lymphocytes. Lipopolysaccharide from E. coli (LPS) proved to be an ineffective mitogen. Phytohemagglutinin (PHA), while producing the highest stimulation indices by DNA assay, appeared to induce predominantly diploid metaphases. Pseudodiploid clonal abnormalities were noted in three out of nine patients, while another four patients showed random structural abnormalities, including translocations, which were indicative of damage. Presence of the A33 antigen, as determined by HLA typing, was noted in five out of nine patients. The increased frequency of this antigen in patients with chronic B cell leukemia is discussed.