Expression of UPR components in unstimulated CLL samples and normal B cells. (A) CHOP and XBP1 RNA expression was quantified by qPCR in CLL samples (n = 40) and normal B cells (n = 7). Expression values were normalized so that the average value in normal B cells was set to 1.0. Graphs show median and individual data points, and the statistical significance of differences between CLL samples and normal B cells (Mann-Whitney test). (B) Correlation between CHOP and XBP1 RNA expression in CLL samples. The line shows results of linear regression, and the statistical significance of the correlation is shown (Spearman correlation). (C) Immunoblot analysis of BIP, total and phospho-eIF2α, PERK, and glyceraldehyde-3-phosphate dehydrogenase (loading control) in normal B cells (2 preparations shown) and CLL samples. Results shown are representative of >30 samples studied across a series of separate immunoblots.