Lymphocyte Subpopulations in the Liver, Spleen, Intestines, and Mesenteric Nodes: An Immunohistochemical Study Using Human Fetuses at 15–16 Weeks

Abstract

The roles of the liver and intestines in lymphocyte differentiation in human fetuses were assessed by immunohistochemical analysis of the thymus, bone marrow, liver, spleen, intestines, and lymph nodes of 15-16 week human fetuses using primary antibodies against IgM, CD3, CD7, CD8, CD10, CD20, CD45RO, HLA-DR, and CD68. The density of immunoreactive lymphocytes was high in the thymus and lymph nodes, but much lower in the bones, liver, spleen, and intestines. The medulla of the thymus contained IgM-positive mature B lymphocytes as well as CD20-positve B lymphocytes. In contrast, CD10-positive immature B lymphocytes were restricted in the cortex. There were no site-dependent differences among axillary, mediastinal, mesenteric, and pelvic lymph nodes. CD68-positive cells were observed at all sites examined. Many HLA-DR-positive round cells were present in the thymus, with fewer in the liver and spleen. The absolute number of lymphocytes was estimated to be 10-fold higher in lymph nodes than in liver. Although limited by analysis of only one fetal stage, these findings suggest that mesenteric nodes are likely to be more important than the liver, spleen, and intestines for lymphocyte proliferation and differentiation in human mid-term fetuses.

Early-Life Compartmentalization of Immune Cells in Human Fetal Tissues Revealed by High-Dimensional Mass Cytometry

“…Moreover, our results provide evidence for tissue-specific compartmentalization of both the innate and adaptive immune compartment early in the second trimester of pregnancy. Altogether, our results confirm and extend previous studies that have analyzed the immune subsets in mucosal and lymphoid tissues from human fetus with immunohistochemical analysis (8, 24) or traditional multi-color flow cytometry (5, 25). Our comprehensive analysis provides a valuable resource that may aid future studies into the development of the human immune system during gestation.…”

Relationship of thymic changes and complications after congenital heart surgery

“…16 The medulla of the thymus contains large numbers of CD20-positive cells and several immunoglobin M-positive cells, and the thymus contributes large numbers of immunoreactive B lymphocytes. 17 Changes in thymic medulla B-lymphocyte distribution were reported by Varga and colleagues 3 to be associated with disordered migration of neural crest cells which are essential in normogenesis of the heart and myocardial function. Furthermore, subtle defects in the B-cell population, particularly a significantly decreased proportion of memory B cells in the B-cell pool, have been described in 2q11.2 deletion syndrome associated with cardiac abnormalities, and abnormal migration of the thymus which may predispose to the development of autoimmunity in these patients, including increased infection and impaired development of natural T-regulatory cells.…”

Regional differences in the density of Langerhans cells, CD8-positive T lymphocytes and CD68-positive macrophages: a preliminary study using elderly donated cadavers

“…We did not consider this rich infiltration to represent evidence of a possible allergic or inflammatory reaction, because the cell density was usually much higher in the epithelium than along and around the submucosal or subcutaneous vessels. We did not use CD4 antibody because of difficulty with immunostaining using specimens from fixed cadavers [ 8 ]. However, most of the round cells scattered in the epithelium were probably positive for CD8 or CD68.…”

“…The second aim of this study was to examine regional differences in the density of macrophages and suppressor T lymphocytes under an assumption that the number of Langerhans cell correlates with that of the other two cell types. Fortunately, in paraffin sections from formalin-treated cadavers, immunostaining of CD8 and CD68 is much easier than that of other immune system markers such as CD4 and HLA-DR [ 8 ]. It is very difficult to obtain frozen specimens from multiple sites in young patients or volunteers.…”