CD99 expression in T-lineage ALL: implications for flow cytometric detection of minimal residual disease

• Published in: Leukemia Vol. 18; no. 4; pp. 703 - 708
• Main Authors: DWORZAK, M. N, FRÖSCHL, G, PRINTZ, D, DE ZEN, L, GAIPA, G, RATEI, R, BASSO, G, BIONDI, A, LUDWIG, W-D, GADNER, H
• Format: Journal Article
• Language: English
• Published: London Nature Publishing 01.04.2004; Nature Publishing Group
• Subjects: 12E7 Antigen; Acute lymphoblastic leukemia; Adolescent; Antibodies; Antigens; Antigens, CD - analysis; Biological and medical sciences; Biomarkers, Tumor - analysis; Bone marrow; Bone Marrow Examination; Cancer research; CD7 antigen; CD99 antigen; Cell Adhesion Molecules - analysis; Child; Child, Preschool; DNA nucleotidylexotransferase; DNA Nucleotidylexotransferase - analysis; Female; Flow Cytometry; Hematologic and hematopoietic diseases; Humans; Infant; Leukemia; Leukemia-Lymphoma, Adult T-Cell - diagnosis; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Lymphatic leukemia; Lymphoblasts; Lymphocytes; Lymphocytes T; Male; Markers; Medical research; Medical sciences; Minimal residual disease; Molecular Diagnostic Techniques; Neoplasm, Residual - diagnosis; Pediatrics; Precursor Cell Lymphoblastic Leukemia-Lymphoma - diagnosis; Sensitivity and Specificity; T-Lymphocytes - immunology; T-Lymphocytes - pathology; Thymus gland; Italy; Austria; Flow cytometry; leukemia; Precusor T lymphoblastic leukemia; Hematology; T-cell; Lymphoproliferative syndrome; Acute; residual disease; Minimal residual disease; Malignant hemopathy; Acute lymphocytic leukemia; CD99
• ISSN: 0887-6924; 1476-5551
• DOI: 10.1038/sj.leu.2403303

Expression of CD99 is higher on immature than on mature T cells. We postulated that this marker could be used to assess minimal residual disease (MRD) in T-lineage acute lymphoblastic leukemia (T-ALL). In diagnostic bone marrow (BM) samples from 27 children with T-ALL, expression of CD99 on leukemic lymphoblasts by flow cytometry was in median 7.7 times higher than on normal T lymphocytes from within the same sample. In 85% of cases, leukemic MFI values were higher than the mean MFI+2 s.d. of normal populations. We applied CD99 to study MRD in 39 follow-up samples from 15 consecutive T-ALL patients, and compared the results with those obtained with the well-established MRD-marker terminal deoxynucleotidyl transferase (TdT). Either antibody was combined in four-color flow cytometry with CD7, surfaceCD3, and cytoplasmicCD3. We found that CD99 was a valid complement to TdT in quantifying T-ALL MRD. Given a considerable interpatient variability, CD99 could be favorably used in nine patients, and TdT in other five patients. Both approaches showed a similar very low nonspecific background throughout 12 weeks from diagnosis (in median 0.002% of nucleated BM cells in patients with non-T ALL). We conclude that CD99 is a highly informative tool for MRD detection in T-ALL, bearing the advantage of surface expression in contrast to TdT.