Clinical features of acute lymphoblastic leukemia subclasses in 28 Thai children--a preliminary study

Twenty-eight Thai children with newly diagnosed acute lymphoblastic leukemia were evaluated for pretreatment characteristic, including immunophenotype of lymphoblast, outcome of treatment, and the correlation among them. By APAAP technique using a panel of eight monoclonal antibodies (HLA-DR, CD 19, CALLA (CD 10), IgM, CD 7, CD 3, CD 4, and CD 8), five subclasses were identified: 67.9, 17.9, 7.1, 3.6, and 3.6 per cent were respectively shown to be common-, null-, mature thymocyte T-, pre B-, and B-ALLs. Clinical features in each subclass conformed to previous reports. All of the 27 evaluable patients attained initial complete remission, but subsequent relapses were noted in 7 patients (25.9%). Three of the 19 cases in the common ALL group relapsed at 6-12 months, whereas, 4 of the 8 cases in the non-common ALL group relapsed at 2-15 months. Probability of relapse at 12 months in the common and non-common ALL groups were 19 and 49 per cent respectively. Disease-free survival from time of remission was shorter in the non-common ALL group. Multivariate analysis of the 6 factors predicting disease-free survival showed that the only strong factor was the immunophenotype of lymphoblast.