- The relative proportions and absolute numbers B-lymphocytes (CD19+), T-lymphocytes (CD3+), NK cells (CD56+CD3-), effector T cells (CD3+CD4+ and CD3+CD8+), HLA-DR+ T cells (CD3+HLA-DR+) and regulatory T cells (CD3+CD4+25+127low) will be quantified with flow cytometry.