Differing reflections of paediatric classical Hodgkin's lymphoma on local and distant immunological microenvironments: A flow cytometric study

Aims To compare immunological microenvironments in local and distant lymphoid tissues in Hodgkin's lymphoma (HL) in children. Methods We have analysed diagnostic bone marrow (BM) samples in 22 and corresponding involved lymph node (LN) in eight and peripheral blood (PB) in eight cases of HL by flow cytometry and sought correlations with clinical features retrospectively. Results While there were significant differences in lymphocyte compositions of BM and LN tissues, the distribution of lymphocyte subsets mimicked each other in BM and PB. CD8-positive cytotoxic T cells predominate the bone marrow in contrast to CD4-positive helper T cells in LN tissue with corresponding CD4/CD8 ratios (0.85 and 5.3, respectively; p=0.002). Additionally, T-large granular lymphocytes population was much higher in BM in comparison to LN tissue (10.5% vs 4.5%; p=0.036). Conclusions Local immunological microenvironment appears to be highly influenced by HL tumour cells and distant site lymphocyte composition reflects immune response to control the neoplastic process.