The recovery of immune system parameters in children following lymphoblastic leukemia therapy - preliminary report

Acute lymphoblastic leukemia (ALL) is the most common pediatric neoplasm. Long-term survival is achieved in approximately 80% of patients. One of the more common complications of ALL treatment is immunosuppression.

The aim of the study is to assess the reconstruction rate of the most important immune system parameters in children after ALL treatment.

The study included 47 children (22 boys, 25 girls) diagnosed and treated for ALL in Department of Pediatric Hematology and Oncology at Wroclaw Medical University. The study used peripheral blood collected at the time treatment was completed and in the first, second, third and sixth months following treatment, then at yearly intervals up to 10 years after treatment. In order to determine the immune status of the tested samples the following parameters were assessed: white blood cell count, absolute lymphocyte count, the proportions of individual subpopulations of lymphocytes - T (CD3 +), Th (CD4 +), Ts (CD8 +), B (CD19 +), NK (CD16 + 56 +), the concentration of immunoglobulins A, G and M, interleukin 10 activity, as well as the expression of ICAM-1 adhesion molecules.

At the end of anti-neoplastic therapy a reduction in both the absolute number leukocytes and various subpopulations of lymphocytes was observed. The lower limits of normal range were achieved about two years after the end of treatment. The concentrations of immunoglobulin IgA, IgG and IgM at the end of treatment were within low normal limits. Normal concentrations of immunoglobulin levels and stability were observed about two years after the end of treatment. There was a slow, steady increase in the production of interleukin-10 and the expression of ICAM-1 adhesion molecules. These results confirm previous observations that after ALL treatment children are in an immunocompromised state for up to 12 months, in terms of both humoral and cellular immunity.

Knowing the average growth trends for the main immune system parameters after ALL treatment can be important in clinical practice for children in whom immune reconstruction proceeds slowly. Predicting the expected time required to restore immune function could be of help, for example in combating infections and planning vaccinations.