Abstract • 185

Objective:To study the frequency of immunoglobulin heavy chain gene (IgH) and T cell receptor (TCR) V δ 2D δ 3 gene rearrangements at time of initial diagnosis in children with acute lymphoblastic leukemia (ALL) and the significance in early diagnosis of central nervous system leukemia (CNSL) and monitoring of minimal residual disease (MRD) from cerebral spinal fluid (CSF) cells. Methods: After extraction of DNA from bone marrow and CSF of patient with ALL, IgH and V δ 2D δ 3 rearrangements were detected by using polymerase chain reaction (PCR) technique or Nested-PCR technique. Result:32 patients were studied in our series. Clonal gene rearrangements of IgH and/or TCR V δ 2D δ 3 were detected in 23 bone marrow samples. The clonal gene rearrangements of V δ 2D δ 3 were found in 9 samples and gene rearrangements of IgH were found in 4 samples of 23 CSF samples from patients during remission induction with clonal gene rearrangement of IgH and/or V δ 2D δ 3 in the bone marrow. Among 37 CSF samples from patients in complete remission, 3 samples had clonal gene rearrangements of IgH, 7 samples had clonal gene earrangements of V δ 2D δ 3.

Conclusion:in detected samples of bone marrow, The rate of IgH gene rearrangement is 47%, and V δ 2D δ 3 gene rearrangement is 38%. Dynamic detection of IgH, V δ 2D δ 3 gene rearrangements in CSF of ALL by PCR technique is an effective tool for clinical early diagnosis of CNSL and is much more sensitive than the CSF routine examination. It plays a guiding role in prevention and evaluating prognosis of CNSL.