Proto-oncogene expression in T-cell chronic lymphoproliferative disorders

Experiments were performed to examine expression of proto-oncogenes and other related genes in ten cases of chronic T-cell lymphoproliferative disorders. The helper vs. suppressor nature of the T-cells was determined using monoclonal antibodies. RNA was isolated from peripheral blood mononuclear cells and/or lymph node sections and 5'-end labelled with γ-32P-ATP. RNA preparations were hybridized under stringent conditions to an excess of nitrocellulose-bound specific cloned DNA; autoradiographs were analyzed by microdensitometry. Hybridizations of PHA-activated T-cells to various probes as well as hybridizations of RNA samples to parent plasmid were negative in all experiments. Results revealed increased expression of K-ras, B-lym, transferrin receptor, α-tubulin and α-interferon in 5/5 helper T-cell lymphoproliferative disorders, while 5/5 suppressor T-cell disorders demonstrated levels of hybridization to these clones no higher than background. However, studies of T-suppressor disorders demonstrated enhanced levels of β-interferon-specific RNA in 5/5 patients, an increase not apparent in T-helper chronic lymphoproliferative disorders. There was no correlation of this pattern of gene expression with the aggressive nature of the disease since T-cells from 2/5 suppressor disorders were actively proliferating