[Immunologic monitoring in children with acute lymphoblastic leukemia during maintenance treatment with regard to co-existing infections].

UNLABELLED: We analyzed the dynamics of changes in the immune system during maintenance treatment of acute lymphoblastic leukemia (ALL). The study was carried out on the group of 40 children aged 2-15 years (mean +/- 3.46), including 31 lower risk patients (Berlin-Frankfurt-Munich protocol--BFM) and 9 high risk patients (New York protocol--NY). Levels of IgA, IgG, IgM and IgE, and subsets of mononuclear cells using flow cytometry were evaluated in the study group every 1-3 months. During maintenance therapy we found markedly reduced leukocytosis, lymphocytosis, and mean values of IgA, IgM and IgG in comparison to healthy children. A gradual increase was observed in the level of IgG, in the percentage and absolute number of B lymphocytes (CD19+) and in helper/suppressor T-cell ratios. In the group of patients treated according to the NY protocol, a decrease was noted in: lymphocytosis, in the percentage of lymphocytes B, in the levels of IgG and IgM, in the percentage and absolute numbers of T lymphocytes, T-helper cells and CD4/CD8 and CD3 RA/RO ratios, compared to standard risk patients. In the course of infection, a transitory increase was observed in activated T-cells, and a rise was found in the number of T-memory cells and monocytes showing the expression of adhesive molecules.

CONCLUSIONS: In the course of maintenance treatment in children with ALL, constant suppression of the immune system, of both humoral and cellular responses, can be observed especially in the group of children treated according to the NY protocol; activation of T lymphocytes and monocytes takes place in the course of infection. Lack of this activation may be a marker of poor prognosis during the infection.