Comparison of the immunohistology of mucosa-associated lymphoid tissue in the larynx and lungs in cases of sudden infant death and controls

Abstract

The respiratory tract of children in the first two years of life, unlike that of adults, contains bronchus-associated lymphoid tissue (BALT) and larynx-associated lymphoid tissue (LALT) with no differences in frequency between SID and control children. Using immunohistochemical methods we examined the distribution of B, T, CD4+ and CD8+ lymphocytes, HLA-D+ cells, CD68+ macrophages and proliferating cells, comparing bronchus-associated and larynx-associated lymphoid tissue of sudden infant death cases and controls. In all groups the lymphoid tissue was organized in lymphoid follicles and parafollicular areas. With no differences in the cellular composition of BALT and LALT the lymphoid follicles contained mainly B lymphocytes with some CD4+ lymphocytes in the germinal centers. Remarkably T lymphocytes of both subset types and B lymphocytes were observed in equal numbers in the parafollicular areas in contrast to gut-associated lymphoid tissue. However, the respiratory tract of young children with no differences between SID and controls might play a similar role in mucosal immunity and might function as an inductive site.

Bronchus-Associated Lymphoid Tissue (BALT) Is Not Present in the Normal Adult Lung but in Different Diseases

“…1). A few proliferating cells positive for Ki67 were seen in the follicles and many cells positive for HLA-DR were evenly distributed over the follicle [15]. This basic structure distribution of lymphoid and nonlymphoid cells was also seen in BALT in pathological conditions, e.g.…”

“…There were no significant differences in the frequencies (36 versus 44%) or in the probability of finding BALT in different age groups. The immunohistology of the lymphocyte subset distribution was also comparable in the lungs of SIDS and trauma children [15]. Thus, BALT is not pathognomonic for SIDS.…”

“…2a). Using immunohistology, it was demonstrated [15] that B lymphocytes were mainly in the follicles, while the T lymphocytes surrounded the B cells ( fig. 2b, c).…”

Density of dendritic cells in the human tracheal mucosa is age dependent and site specific

“…In studies of SIDS, no differences have been found in the mucosal immunology of the respiratory tract. 35 It is therefore unlikely that the data are biased for SIDS.…”

The larynx as an immunological organ: immunological architecture in the pig as a large animal model

“…However, studies in man [1][2][3] and animals [4,5] show that the larynx does contain immunological tissue. A minor part of this has been reported to be present in the form of epithelial follicles (larynx-associated lymphoid tissue: LALT [1]) in an age-and disease-dependent manner [1,6]. However, as with studies of gut [7] and trachea [8], the majority of immunologically active cells appear to be present in a more diffuse, although still organized manner [3,4].…”