From the Research
T lymphocytes are the predominant cell type found in the periarteriolar lymphatic sheaths (PALS) in the white pulp of the spleen. These T cells form a cuff-like arrangement around the central arterioles, creating the PALS structure. This organization is crucial for immune function as it allows T cells to interact with antigen-presenting cells and respond to blood-borne pathogens. The T cells in the PALS are mainly CD4+ helper T cells, with some CD8+ cytotoxic T cells also present, as supported by studies such as 1 and 2. This arrangement facilitates immune surveillance and the initiation of adaptive immune responses. The white pulp's organization, with T cells in the PALS and B cells in adjacent follicles, enables efficient immune cell interactions and antibody production in response to antigens filtered from the blood by the spleen.
Some studies, such as 3, have suggested that B-lymphoid lineage cells can be found in the periarteriolar area in certain immunodeficient conditions, but this does not change the general principle that T lymphocytes are the predominant cell type in the PALS under normal conditions. The study 3 highlights the importance of immunologic phenotyping in understanding the nature of immunodeficiencies, but it does not alter the fundamental composition of the PALS in healthy individuals.
The most recent and highest quality studies, such as 2, provide insights into the dynamics of bacterial infection and antigen presentation to CD8+ T cells within the splenic white pulp, further emphasizing the critical role of T lymphocytes in this region. Therefore, based on the strongest and most recent evidence, T lymphocytes are the cell type predominantly found in the periarteriolar sheaths in the white pulp of the spleen.