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The intestinal mucosa contains a highly specialized immune system which plays a central role in the induction of immune reactions. In the small bowel, Gut-Associated Lymphoid Tissue (GALT) is organized in lymphoid aggregates which are known as Peyer’s Patches (PP). Even though human PP involvement in systemic immunity has been described, little is known about their anatomy and morphology and viability. The aim of this study was to examine PP according to their macroscopic anatomy, distribution and cell viability after death. Specimens from the distal ileum were obtained from 72 serial autopsy cases: PP were identified and, parts of them were analyzed for histological examination. Moreover, viability of recovered PP cells was assessed by the trypan blue exclusion test. Most of the PP (90%) were situated on the antimesenteric border of ileum, and the greatest density of PP occurred in the most distal segment. The number of PP varied with age, with the maximum number observed in 21- to 30-years old cadavers. Histological examination showed their remarkable architectural preservation at different post-mortem intervals (PMI), while the mucosal surface underwent autolysis. In 56% of cases PP cells were still viable, especially at PMI < 24 hours after death. These data confirm that human PP are still well preserved in a remarkable percentage of cadavers also several hours after death, and their availability may be helpful in various fields of research. [ABSTRACT FROM AUTHOR]

Pro-inflammatory mediators hold important functions in human body in response to infection, trauma and vascular disease. However, their action is down regulated by the release of anti-inflammatory cytokines, thus restoring a balance which reflects the immune status of a given individual. Recent studies have stressed out the importance of circulating levels of cytokines for forensic purposes even if there is a lack of studies regarding the role of post-mortem mucosa-associated lymphoid tissue. In this respect, Peyer’s patches (PP), represent one of the most important immunological site of the body and the major component of the gut -associated lymphoid tissue. The aim of this study was to evaluate post-mortem PP immune response in 40 serial autopsy cases of people who died from natural and traumatic death. The study examined spontaneous release of the following cytokines by fresh isolated PP cells: interleukin (IL)-12, tumor necrosis factor (TNF)-α, IL-10, IL-6, IL-1β, and IL-8. Results will show that higher levels of TNF-α, IL-6, IL-1β, and IL-8 are statistically correlated with the traumatic death group. From a forensic point of view these data demonstrate that fundamental lymphoid organs, such as PP, may have a potential in diagnosing the cause of death. [ABSTRACT FROM AUTHOR]