Distribution of T and B lymphocytes in lymphoid tissue of infants and children.

Normal lymphoid tissue from children undergoing elective surgery was examined for T and B lymphocyte distribution. Although established for peripheral blood and bone marrow, T and B lymphocyte distributions have not been previously reported for lymph nodes, appendix, thymus, and spleen tissues in children. Thymus-dependent T cells were determined by the sheep erythrocyte rosette technique, and thymus-independent B cells were determined by the fluorescent labeling of surface immunoglobulins A (IgA), G (IgG), and M (IgM). Fifty percent of lymph node cells were either T or B cells; 65% of these cells were T lymphocytes, whereas 58% of B cells were of the IgM subclass. Less than half of the appendix cells were either T or B cells; 47% of these were T lymphocytes, and the remainder B lymphocytes had subclass distribution similar to that of lymph nodes but different from peripheral blood and bone marrow where B cells bearing IgG predominate. Thymus tissue contained 43% T cells and less than 1% B cells, but the spleen was composed largely of B cells, predominantly of the IgM type. Lymphoid tissue from nine children with either inflammatory or neoplastic diseases were studied and included for contrast. This paper establishes relative distribution values for T and B lymphocytes in normal lymphoid tissue and points out the potential use of this technique to quantitate deviations from normal in certain inflammatory and neoplastic diseases.