[Evaluation of selected parameters of cellular immunity in children with osteosarcoma at diagnosis]

The causes of osteosarcoma (OS) and effector mechanisms of the immune response against OS and other neoplastic diseases remain unknown. According to current knowledge, the major role is attributed to cytotoxic T lymphocytes, NK, NKT and Tăä lymphocytes, which are engaged directly in the destruction of the tumour cells. Helper T lymphocytes (CD4+) and indirectly B lymphocytes are of special importance. There is sparse data on the state and efficiency of the immune system in children with neoplastic disease, with bone tumours in particular. THE AIM OF THE STUDY was the evaluation of selected elements of cellular immunity in children with osteosarcoma at the time of diagnosis.

The study was performed on a group of 44 children with osteosarcoma, aged from 6 to 20 years (median 15.0 years). The control group consisted of 22 children of the same age (median 14.5 years) without the diagnosis of neoplastic disease and active inflammatory state. T lymphocytes with their subpopulations, activated T lymphocytes (CD3+/HLA-DR+), B lymphocytes, NK and NKT cells were analyzed in peripheral blood using the flow cytometry method. Examinations were performed before the therapy - in the diagnostic period.

A lower number of peripheral blood lymphocyte population in children with osteosarcoma at diagnosis, compared to the control group was observed. The differences concerned T lymphocytes CD3+(1609.0 vs 3038.0 kom/μl, p<0.001) CD4+(598.0 vs 1071.0 kom/l; p<0.001) and their cytotoxic subpopulation CD8+ (386.0 vs. 866.0 cells/μL; p<0.001), activated T lymphocytes CD3+/HLA-DR+(39.0 vs. 81.0 cells/μL; p<0.025), B lymphocytes CD19+(205.0 vs. 381.0 cells/μL; p<0.025) and NK cells (161.0 vs. 339.0 cells/μL; p<0.005). The number and percentage of peripheral blood lymphocytes in children and youth with osteosarcoma at diagnosis is over 50% lower compared to the patients without neoplastic disease.

1. The general analysis of peripheral blood without differentiating lymphocyte subpopulations is insufficient to determine disturbances which are forming in the immune system of patients developing the neoplastic disease. 2. The course of the neoplastic disease (osteosarcoma) in patients of developmental age is very diverse, and associated with individual biological variation. 3. The evaluation of the immunologic status in patients with osteosarcoma may have prognostic meaning for the further course of the disease, may prevent the formation of unfavourable clinical changes, and be the basis for correcting the administration of cytostatic agents.