The prognostic significance of dipeptidyl peptidase IV (CD26) expression in B-cell chronic lymphocytic leukemia

Background B-cell chronic lymphocytic leukemia (B-CLL) has a highly variable clinical course. The leukemic transformation is initiated by specific genomic alterations, impairing apoptosis of clonal B-cells. Many prognostic factors have been identified, yet research studies continue to identify new prognostic factors to predict the course of B-CLL. Aim This study aimed to evaluate the prognostic value of CD26 expression in Egyptian patients with B-CLL and assess its correlation to other clinical and laboratory parameters with known prognostic significance. Patients and methods A total of 30 Egyptian adults with newly diagnosed B-CLL and 15 healthy participants (control group) were subjected to full study of clinical, laboratory, flow cytometry, and cytogenetic data. Testing of CD26% expression was done by flow cytometry-immunophenotyping. Detections of ataxia telangiectasia mutated, P53, 13q14 deletions, and trisomy 12 were performed using fluorescent in-situ hybridization. Immunoglobulin heavy-chain variable mutational status was done by PCR. Moreover, smudge cells % was calculated by microscopic evaluation of stained blood smears. Results A statistically significant increase of CD26% expression in patients with B-CLL in comparison with normal participants was documented (P<0.001). CD26% expression on B-CLL was statistically significantly correlated with advanced modified Rai's clinical stage of B-CLL at diagnosis (P<0.001), hepatomegaly (P=0.003), low hemoglobin level (P=0.049), low platelets count (P=0.034), high lactate dehydrogenase blood levels (P=0.001), and atypical lymphocytes % (P=0.049). Correlation studies with other prognostic factors revealed statistically significant correlations between CD26% expression and CD38% (P<0.001), ZAP-70% (P=0.007), the unmutated status of immunoglobulin heavy-chain variable (P<0.001), and low % of smudge cells (P<0.001). Conclusion CD26% expression could be considered as an adverse prognostic predictor being associated with high-risk markers in B-CLL. It can be routinely used, as a part of immunophenotyping panel, in third world countries at diagnosis, for prognosis, risk-stratification, and tailoring of therapy. </p>