Peyerféle

Peyerféle, more commonly known as Peyer’s patches, are organized lymphoid aggregates located primarily in the mucosa and submucosa of the ileum, the final portion of the small intestine. They are part of the gut-associated lymphoid tissue (GALT) and are named after the Swiss anatomist Johann Conrad Peyer, who described them in the 17th century.

Peyer’s patches consist of grouped lymphoid follicles, often with germinal centers, and are interspersed with other immune cells. They are most numerous in the distal ileum, where their density supports robust immune surveillance of contents passing from the small intestine into the large intestine. The epithelium over Peyer’s patches contains specialized M cells that sample luminal antigens and transport them to underlying immune cells, facilitating antigen presentation and initiation of immune responses.

Functionally, Peyer’s patches play a central role in mucosal immunity. They contribute to the generation and maturation of B cells and T cells, support class switching to immunoglobulin A (IgA) production by plasma cells, and help establish immune tolerance to dietary antigens and commensal microbes. They are connected to the systemic immune system through the mesenteric lymph nodes and the thoracic duct, linking local gut immunity to broader immune responses.

Clinically, Peyer’s patches are considered a key component of oral vaccine sites and can undergo changes such as hyperplasia in certain infections or inflammatory conditions. Their integrity is important for effective mucosal defense, particularly against enteric pathogens.