Functional gene expression after BCR cross-linking. Each time point is shown as a column, with 4 time points for unstimulated and 4 time points for stimulated cells, for each of the 18 subjects (6 healthy and 12 CLL patients) for a total of 144 DNA chips. Nine hundred twenty-five of 54 675 probe sets satisfied the filtering criteria. Unsupervised hierarchical clustering analysis of functional gene expression after BCR cross-linking.