The expression of gene for μ-calpain, but not that of m-calpain and calpastatin, is significantly increased at the transcriptional level compared with healthy B cells.

(A) Representative results of an RT-PCR estimation of the activities of μ-, m-calpain, and calpastatin genes in 3 B-CLL samples and 3 samples of enriched B cells of healthy, age-matched individuals. The β-actin gene product was used to assure that an equal amount of total mRNA was analyzed. (B) Mean results of 3 experiments similar to those shown in panel A. The difference (Student t test) between the amounts of gene product for μ-calpain was statistically significant at the level of P < .01 (*).