Gut and Bronchus Associated Lymphoid Tissue: An Overview

Abstract

Just over 300 years ago, Peyer (1) described structures present in the wall of the ileum before the ileo-cecal junction. Because, when these were pressed, it appeared that fluid was coming from them. He thought that they were glands which had something to do with the digestive process. It has been known for 100 years or more that Peyer’s patches were in reality a collection of lymphoid aggregates and that these were found, some in constant positions, in the gastrointestinal tract from the jejunum distally, including one or two in the colon. In 1875, Klein (2) described lymphoid tissue within the wall of the bronchus in a number of species including man. On the basis of their morphology, he concluded that they were analogous in function to the Peyer’s patches and tonsils.