Study of central nervous system involvement in children with acute leukemia in relation to different immunophenotypes before and during treatment

ABSTRACT

Central nervous system [CNS] involvement remains a problem in acute Ieukemias [AL] despite the fact that prophylaxis with intrathecal [IT], systemic high dose chemotherapy and radiotherapy have greatly reduced its incidence. The relationship between the immunophenotypes of AL and development of CNS disease is controversial. The present study included 40 children with newly diagnosed acute leukemia, 36 patients with ALL and 4 patients with AML. They were 23 males and 17 females. Their age ranged from 2-12 years with a mean age of 6.06 +/- 2.59 years. A panel of monoclonal antibodies were used for classifying the Ieukemias into different immunophenotypes. The most common immunophenotype of ALL cases [56%] was early pre-B [CD19, CD22 and CD10]. No CD10 [CALLA] negative cases were detected in our series. Two cases showed cytoplasmic immunoglobulin [Clg] indicating a more mature pre-B immunophenotype. T cell immunophenotype was detected in 14 cases mainly CD2, CD3 and CD7.AML immunophenotype was detected in 4 cases showing CD13 and CD33. Seven cases [17.5%] showed clinical symptoms and signs of CNS involvement at initial diagnosis whereas 8 cases [20%] showed blast cells in CSF. The majority [75%] of CNS disease cases [6 out of 8 cases] had a T cell immunophenotype, while 25% [2 out of 8 cases] were 8 cell lineage. The difference between the 2 groups was significant [P=<0.001]. During follow-up, 5 cases developed CNS relapse. Four of them [80%] were of T cell immunophenotype and only one case [20%] was of B cell lineage [pre 8 cell ALL]. Only one case of CNS relapse did not have CNS disease at initial diagnosis and was of T cell immunophenotype. Four of CNS relapse cases occurred early in the first year of the disease. In view of the poor prognosis of patients with CNS disease and relapse and the higher incidence of these events in T cell ALL children, these patients may need intensive systemic and CNS directed therapy to improve their outcome: