The immunoarchitecture of the normal human lacrimal gland. Relevancy for understanding pathologic conditions.
Academic Article
Overview
abstract
To delineate the immunoarchitecture of the normal human lacrimal gland, monoclonal antibodies that detect B- and T-lymphocyte, macrophage, and dendritic cell lineage, subset, and differentiation-associated antigens were used in combination with highly sensitive tissue-section immunoperoxidase techniques. Plasma cells, identified with monoclonal antibody OKT10, represented the predominant mononuclear cell population, accounting for 53.9% of all mononuclear cells present. A qualitative study of plasma cell cytoplasmic immunoglobulin heavy-chain expression in deparaffinized, formalin-fixed tissue sections showed that the vast majority of these plasma cells contained IgA. Rare plasma cells contained IgG, IgM, or IgD. T-cells, identified with monoclonal antibody OKT3, represented the second most common cell type in the normal human lacrimal gland, accounting for 40.3% of all mononuclear cells present. T cells were located predominantly in lymphocytic foci and singly in the interstitium. T8 antigen-positive (suppressor/cytotoxic) T cells predominated over T4 antigen-positive (helper) T cells, averaging 25.2 and 14.7%, respectively. The overall mean T4/T8 ratio was 0.56. T8 antigen-positive T cells were the most numerous cell population outside aggregates and follicles, being distributed almost equally between the acini and the ducts (49%) and the interstitium (51%). Only 16% of T4 antigen-positive cells preferred glands or ducts to the interstitium. B cells, identified with monoclonal antibody BL9, represented only 5.7% of all mononuclear cells present. B cells were exclusively found in the centers of primary and secondary follicles. The majority of the surface immunoglobulin-positive B cells expressed IgM, fewer expressed IgD, and still fewer expressed IgG or IgA. Rare LeuM1+ OKM1+ macrophages were present in the center of B-cell follicles, where rare OKT6+ dendritic cells and activated T cells (IL-2+) were also discovered. These results support the concept that the lacrimal gland belongs to the mucosa-associated lymphoid system.
