Comparison of mitogen-induced proliferation in child and adult healthy groups by flow cytometry revealed similarities

The proliferation of antigen-specific lymphocyte clones, the initial step in acquired immunity, is vital for effector functions. Proliferation tests both in immunology research and diagnosis are gaining attendance gradually, while the use of adult healthy individuals as controls of pediatric patients is a question. This study aimed to investigate and compare mitogen-stimulated proliferation responses of total lymphocytes and T- and B-lymphocyte subsets in adult and children healthy donors. Nineteen children and 20 adult healthy donors were enrolled in this study. Peripheral blood mononuclear cells (PBMCs) purified from peripheral blood samples of the donors, by Ficoll gradient centrifugation, were stained with CFSE and were cultured in a 37 celcius CO2 incubator for 120 h with the absence or existence of polyclonal activators: PHA and CD-Mix. After cell culture, PBMCs were stained with monoclonal antibodies against CD4 and CD19, and proliferation percentages of CD4(+) T and CD19(+) B cells, together with total lymphocytes were determined by flow cytometry. This study revealed similarities between children and adult age groups, concerning mitogenic stimulation of the lymphocytes. The only difference was a significantly high proliferation of pediatric CD4(+) T cells in response to PHA. CD4(+) T cell responses against PHA were inversely correlated with altering age. When pediatric individuals were distributed into age groups of 0-2 years, 3-5 years, and 6-18 years, PHA responses of CD4(+) cells were found to be diminished with advancing age. These findings propose the possibility of enrollment of adult healthy individuals as controls for pediatric patients.