DETECTION OF D13S25 DELETION ABNORMALITY BY (FISH ) ANDEXPRESSION OF ADHESION MOLECLE VLA4 IN B-CHRONIC LEUKEMIA

Abstract

In the present study we examined 13q deletion abnormalities by G-banding analysis in 40 patients with B-chronic lymphocytic leukemia and by fluorescence in situ hybridization (FISH) with a locus specific identifier probe in 23 of them. We detected chromosome 13 deletion in only 4 cases by G-banding. In contrast 13 cases (56.5%) with D13S25 deletion were detected by interphase FISH and 9 of them could only diagnosed by this technique. 5 cases showed monoallelic deletion and 8 cases showed biallelic and monoallelic deletion. There was no significant correlation between D13S25 deletion and any of the studied prognostic factors. We further investigated the expression of the dual specific adhesion molecule, VLA-4 (CD49d/CD29) on lymphocytes obtained from the 40 patients with B-chronic lymphocytic leukemia and compared it with fifteen patients with reactive lymphocytosis. The mean of CD49d expression in patients was lower than control group and the patients in stage 0 and II had even lower CD49d expression whereas patients in stage IV had relatively higher CD49d levels. There was a significant association between CD49d expression and old age, lymphadenopathy, atypical morphology, and percent of lymphocytes in the bone marrow. However, there was no correlation between its expression and sex, splenomegaly, absolute lymphocytic count, light chain expression and D13S25 deletion. Our data show that D13S25 deletion can diagnosed accurately by FISH on the one cell level in a high frequency among patients with B-CLL and biallelic deletion occurs in a substantial number of patients. In addition, CD49d expression may give clues in disease dissemination and prognosis.