Telomerase Immunocytochemistry in Lymphocytes From Chronic Lymphocytic Leukemia

Human telomerase reverse transcriptase (hTERT) is detectable in normal progenitor cells, tumor cells, and B-cell chronic lymphocytic leukemia (B-CLL) cells. hTERT expression, in addition to other prognostic factors, is reportedly associated with a poor prognosis in B-CLL. In this study, we aimed to analyze and compare hTERT immunoexpression in B-CLL bone marrow (BM) lymphocytes and benign pleural effusion lymphocytes. Standard cytologic analysis and immunocytochemical assessment of hTERT immunoexpression were performed in BM lymphocytes from 25 patients with B-CLL and pleural effusion lymphocytes from 18 patients with pneumonia and effusion-reactive lymphocytosis. The percentages and score values of hTERT nucleus (TN)-immunopositive BM lymphocytes in patients with CLL were significantly higher than those for reactive effusion lymphocytes with no or few TN-immunopositive lymphocytes. The appearance of TN immunopositivity in CLL lymphocytes showed mainly numerous prominent or large dots, and diffused TN immunopositivity was detected; in contrast, TN-immunopositive benign effusion lymphocytes had one or few immunopositive nuclear dots. Further investigations are needed to clarify whether lymphocyte TN immunopositivity can reveal subgroups of patients with CLL with a worse prognosis and whether there is a reliable difference in TN immunopositivity between CLL and benign effusion lymphocytes.