Affiliations: [a] Clinical and Chemical Pathology Department, Kasr Al Aini, Faculty of Medicine, Cairo University, Cairo, Egypt | [b] Clinical Pathology Department, National Cancer Institute, Cairo University, Cairo, Egypt | [c] Pediatric Oncology Department, National Cancer Institute, Cairo University, Cairo, Egypt | [d] Department of Medical Oncology, National Cancer Institute, Cairo University, Cairo, Egypt
Correspondence:
[*]
Corresponding author: Samah Abd Elhamid, Clinical and Chemical Pathology Department, Kasr Al Ainy Faculty of Medicine, Cairo, Egypt. Tel.: +22 3654480; E-mail:samah_cpath@yahoo.com
Abstract: BACKGROUND: CD99 was first isolated as an antigen on the T acute
lymphoblastic leukemia cells. It has been shown to participate in T cell
adhesion and is widely expressed on a variety of hematopoietic and
non-hematopoietic cell types. AIM OF WORK: Detection of the
expression pattern of CD99 on leukemic and normal T cells and assessing the
possibility of its use as a tool for the diagnosis and monitoring of T-ALL
cases. METHODOLOGY: We used flow cytometry technique to determine
the expression level of CD99 in 62 newly diagnosed T-ALL patients. Patients
were followed up for the presence of minimal residual disease on day 15 and
day 42 post-therapy. 20 age and sex matched healthy controls were enrolled
in our study. RESULTS: CD99 was expressed in all T-ALL patients,
with a higher median expression level when compared to controls (58.5%
versus 1.38%, p< 0.001). On day 42 post-therapy, 100% of follow up
patients who had initial CD99 expression ≤ 50% had no minimal
residual disease, while only 45.5% of those who had initial CD99
expression > 50% had no minimal residual disease (P= 0.03). There was no
significant influence of CD99 expression on the 1-year overall survival
probability (P= 0.82). CONCLUSION: CD99 could be used to complement
current strategy relying on TdT for diagnosis and monitoring of minimal
residual disease during the post-therapy follow up of T-ALL patients.
Further studies are needed to confirm these findings.
Keywords: CD99, T acute lymphoblastic leukemia, disease free survival
