Histological and immunohistochemical assessment of the immunological aspect of certain cells in human palatine tonsils

Tonsils contain four specialized lymphoid compartments that together are involved in immune functions. The capacity of tonsillar lymphocytes to counter infections may be altered during one's lifetime. The classification of lymphocytes by CD antigen expression is now widely used in clinical medicine and experimental immunology. The present work was designed to study the distribution of CD4 and CD8 antigen expression in T lymphocytes in human tonsils at different periods of life. Sixty-two tonsillar specimens were obtained from still birth infants and from children aged 1-9 years. Paraffin sections were prepared and stained with H and E and with immunohistochemical stains to demonstrate CD4 and CD8 T lymphocytes. The distribution of these cells in the different components of the tonsils was evaluated with an image analyzer. The obtained data were statistically analyzed using SPSS. There was a significant increase in the distribution of stained CD4 and CD8 T lymphocytes in the interfollicular areas, mantle zones of lymphoid follicles, and partially in the germinal centers of the examined tonsils with the advancement of age. Activated T lymphocytes differentiate into several subtypes, among which are CD4 and CD8 cells. These types of T lymphocytes express surface antigens, which can interact with different foreign pathogens

Autoimmune lymphoproliferative syndrome (ALPS): a rare cause of immune cytopenia.

Autoimmune Lymphoproliferative syndrome (ALPS) is an inherited disorder manifesting with autoimmune cytopenia, lymphadenopathy and splenomegaly. The differential diagnosis includes infections, autoimmune disorders or malignancies. The disease is characterized by accumulation of double negative (CD3+ CD4- CD8-) T cells (DNT) in the peripheral blood. We describe a case and review the literature.

Immunoregulation by processed immunoglobulin on B-cells.

According to Jerne's network hypothesis, the unique amino acid sequences of Ig variable regions, that is, the idiotypic determinants can function in immunoregulatory mechanisms and cellular interactions. Indeed, Id-specific T-cells (mostly CD4+) have since been described, but the nature of Id-positive Ig on B-cells involved in recruiting T-cells is unclear. Studies from our ongoing investigation presented here clearly show that Id can evoke both CD4+ and CD8+ T cells, and exist not only as the integral components of a bona fide antigen-binding receptor Ig but also as distinct molecular entities in processed forms on the cell surface of B-lymphocytes. Using a B-cell hybridoma, 2C3, that expresses anti-hapten (phthalate) antibody receptors on the cell surface, we induced both Id-specific CD4+ and CD8+ T effector cells. The CD4+ T cells were suppressive and mediated generation of Id-loss 2C3 variants, whereas CD8+ T cells were highly cytotoxic and selectively eliminated 2C3 cells both in vitro and in vivo. These effector cells could be induced by cell membrane-associated Ig but not by its soluble form, secreted by 2C3 cells. Antibodies to MHC class I but not class II molecules were inhibitory to this induction. Furthermore, brefeldin A (BFA), an inhibitor of MHC class I mediated processing, blocked induction of CTL but had no effect on the expression of membrane Ig. Moreover, chloroquine, an inhibitor of class II-mediated processing, had no effect. A few reports have recently appeared indicating that an exogenous Ig can be processed by B-cells in the context of MHC class II proteins.(ABSTRACT TRUNCATED AT 250 WORDS)