Proliferation of T-ALL cells sorted for CD34 and CD4 or CD7 in suspension culture. ALL cells from 8 patients were sorted for expression of CD34 and CD4 (A) and cells from 7 patients were sorted for expression of CD34 and CD7 (B). The proliferative capacity of each of the sorted subfractions and unsorted controls were evaluated in SC. Cultures were maintained with weekly half-media changes, and absolute cell counts derived from each sorted population and unsorted controls were determined by flow cytometry at weeks 1, 3, 5, and 6. These values were then used to calculate the proportion of the total viable cells, represented by each sorted population. The proportion of the total cells derived from each sorted subfraction is presented as the mean plus or minus the standard error (SE).