Aims: To assess the value of measuring subpopulations of T and B lymphocytes in children with bone tumours as an immunodiagnostic procedure in primary diagnosis of tumours.

Methods: In this prospective study blood samples were obtained from 36 patients aged 04–16 presenting with bone tumours in Cappagh Orthopaedic Hospital. Measurements in Immunology laboratory were based upon the principle of Ortho Cytoron Absolute flowcytometry. Levels of CD3 (Total T cells), CD4 (Helper cells), CD8 (Suppressor cells), Helper/Suppressor ratio and CD19 (B cells) were measured. Histological diagnosis of tumours was obtained by histopathological investigation of biobsy samples and flow cytometry results allocated accordingly.

Results: Of 36 patients, 12 (33.12%) had osteosarcoma, 10 (27.7%) Ewing’s sarcoma, 4 (11.1%) giant cell tumour and 10 (27.7%) osteomyelitis. Median values of lymphocytes were within normal values in patients with tumours other than oseomyelitis. In children with osteomyelitis median values were: CD3 2456, CD4 1479, CD8 929, Help/Sup ratio 1.8 and CD19 560 and all significantly raised. Confidence intervals were: CD3 467, CD4 292, CD8 470, and CD19 148. IN order to confidently outrule or confirm the diagnosis of osteomyelitis we measured the cut off point values of lymphocytes (the highest value in other patients groups). The cut off point values were found to be: CD3 2420, CD4 1400, CD8 873 and CD19 550.

Conclusions: The main use of measuring T and B lymphocytes response is in establishing the correct diagnosis between suspected osteomyelitis and other bone tumours. The CD3, CD4, CD8 and CD19 were significantly raised in children with osteomyelitis in contrast to other causes. Levels of CD3, CD4, CD8 and CD19 above the presented cut off values are an important and accurate confirming factor for the diagnosis of suspected osteomyelitis.