What is reactive lymphoid hyperplasia?

Answer 1

Reactive lymphoid hyperplasia is a condition in which the lymph tissues of the body (lymph nodes and spleen, primarily) enlarge as they respond to a viral or bacterial infection. The reason they enlarge has to do with the way that lymph tissues work. The lymph tissues of the body (also known as the reticuloendothelial system) are one of our lines of defense against outside invasion. Blood passes through these tissues, where it is monitored by specialized cells that live in the lymph tissues. If these cells detect an invader, they activate. In this activation process, the cells enlist the help of the reticuloendothelial system, causing it to produce millions of cells just like itself - all of which are capable of either (a) producing antibodies directed against the invader or (b) attacking the invader directly and phagocytizing ("eating") it. This distinction depends mainly on the type of pathogen detected; some pathogens provoke an antibody response and some provoke a cell-mediated response. In the process of reacting to the invasion and subsequent alarm, and while ramping up production of these cells, the lymph tissues enlarge. They do this because they become engorged with the immature cells before those cells can be released to do their job out in the body, and also partially because of the increase in blood flow and increase in metabolic activity in these tissues. The term hyperplasia comes from the Greek root words hyper-, which means an increase, and plastein, a verb which means to form or make. The combination of the two creates a word whose meaning is basically "to make bigger".