[Defective expression of B7.2 in B cell chronic lymphocytic leukemia B cells]

To investigate the expression of B7.1 and B7.2 molecules in peripheral B cells of patients with chronic B cell lymphocytic leukemia (BCLL) and to study the relationship between B7.1 and B7.2 expression and pathogenic mechanism of BCLL.

Peripheral blood mononuclear cells (PBMC) were separated by Ficoll-Hypaque lymphocytes separation medium from 25 normal persons (normal control group) and 23 BCLL patients (BCLL group) which were further divided into two groups, phase 0-II group and phase III-IV group. Flow cytometry (FCM) was used to analyze the B7.1 and B7.2 expression in peripheral B cells after the mononuclear cells had been cultured for 24 hours in vitro.

The B7.2 expression in B cells of BCLL patients was significantly lower than that in normal control group (P < 0.05). No statistically significant difference was found in the B7.1 expression and co-expression of B7.1 and B7.2 between the BCLL group and normal control group. The average B7.2 expression rates in patients of phase 0-II group and phase III-IV group were 25% +/- 17% and 17% +/- 8% respectively without statistically significant difference.

The B7.2 expression in B cell of patients with BCLL is defective, which may be one of the pathogenic mechanisms of chronic BCLL and a major cause why the body fails to clear the BCLL cells via immunological means.