The prognostic value of flow cytometry determination of CD38 and CD49d on leukemic cells of Argentinian CLL patients.

CORDINI, GREGORIO; GAMBERALE ROMINA

Edinburgh

Workshop; XVIII International Workshop on Chronic Lymphocytic Leukemia,; 2019

CLL shows a highly variable clinical course, which can be predicted by several biologic markers, including the mutational status of immunoglobulin heavy variable (IGHV) gene, genomic abnormalities, and expression of CD38 and CD49d. The aim of this study was to determine whether combined flow cytometry determination of CD38 and CD49d can be used to predict time to first treatment (TTFT) in our cohort of CLL patients. The study includes peripheral blood samples from 159 patients affected by typical B-CLL. The median age at diagnosis was 73 years with a male to female ratio of 1.65. The median follow-up of our patients was 10.3 years; 60 out of 159 required treatment (37.7%) with a median TTFT of 8.3 years (95% CI 5.7-11.8). The distribution of clinical stages at diagnosis according to Rai?s criteria was: 36.8%, stage 0; 26.5%, stage I; 14.7%, stage II; 5.9%, stage III; 16.2%, stage IV. Fluorescence in situ hybridization (FISH) testing was available for 69 patients: del13q14 26.9%, del11q22 7.2%, del17p13 15.9% and trisomy 12 15.2%. The IGHV mutational status, available for 82 out of 159 cases showed 63.4% of mutated- and 36.6% of unmutated-IGHV gene configuration. The expression of CD38 and CD49d on CD19+ cells was evaluated in our laboratory by three-color immunofluorescence, as previously described (1), employing PE-conjugated anti-CD38 or anti-CD49d monoclonal antibodies (mAbs) with PerCP-conjugated anti-CD19 mAbs. Patients with ≥7% of CD19+ cells expressing CD38 were considered CD38+ (2) and patients with ≥30% of CD19+ cells expressing CD49d were considered CD49d+ (3). Figure 1A shows the percentage of CD19+ cells expressing CD38 and CD49d for each of the 159 CLL patients. We found that 46 patients (28.9%) were CD38+ and CD49d+, while 67 patients were negative for both markers (42.2%). The remaining samples were discordant for the expression of CD38 and CD49d: 28 patients (17.6%) were CD38+CD49d- and 18 patients (11.3%) were CD38-CD49d+. As previously described (4), the association between the two antigens was highly significant (p