vein. Tonsillar crypts Palatine tonsils consist of approximately 15 crypts, which result in a large internal surface. The tonsils contain four lymphoid compartments that influence immune functions, namely the reticular crypt epithelium, the extrafollicular area, the mantle zones of lymphoid follicles, and the follicular germinal centers. In human palatine tonsils, the very first part exposed to the outside environment is tonsillar epithelium. Function Local immunity Tonsillar (relating to palatine tonsil) B cells can mature to produce all the five major immunoglobulin (Ig, aka antibody) classes. Furthermore, when incubated in vitro with either mitogens or specific antigens, they produce specific antibodies against diphtheria toxoid, poliovirus, Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, and the lipopolysaccharide of E. coli. Most Immunoglobulin A produced by tonsillar B cells in vitro appears to be 7S monomers, although a significant proportion may be l0S dimeric IgA. In addition to humoral immunity elicited by tonsillar and adenoidal B cells following antigenic stimulation, there is considerable T-cell response in palatine tonsils. Thus, natural infection or intranasal immunization with live, attenuated rubella virus vaccine has been reported to prime tonsillar lymphocytes much better than subcutaneous vaccination. Also, natural infection with varicella zoster virus has been found to stimulate tonsillar lymphocytes better than lymphocytes from peripheral blood. Cytokine action Cytokines are humoral immunomodulatory proteins or glycoproteins which control or modulate the activities of target cells, resulting in gene activation, leading to mitotic division, growth and differentiation, migration, or apoptosis. They are produced by wide range of cell types upon antigen-specific and non-antigen specific stimuli. It has been reported by many studies that the clinic outcome of many infectious, autoimmune, or malignant diseases appears to be influenced by the overall balance of production (profiles) of pro-inflammatory and anti-inflammatory cytokines. Therefore, determination of cytokine profiles in tonsil study will provide key information for further in-depth analysis of the cause and underlying mechanisms of these disorders, as well as the role and possible interactions between the T- and B-lymphocytes and other immunocompetent cells. The cytokine network represents a very sophisticated and versatile regulatory system that is essential to the immune system for overcoming the various defense strategies of microorganisms. Through several studies, the Th1 and Th2 cytokines and cytokine mRNA are both detectable in tonsillar hypertrophy (or obstructive sleep apnea, OSA) and recurrent tonsillitis groups. It showed that human palatine tonsil is an active immunological organ containing a wide range of cytokine-producing cells.