Cluster formation in human nasal polyps. A light- and electron-microscopic investigation

There is evidence from many functional studies, that lymphocytes and macrophages can cooperate during the immune response. In human nasal polyps, cell clusters were demonstrated which consisted mainly of macrophages and lymphoid cells. Within the clusters, the cells showed intimate physical contacts which were performed by microvilli of varying lenth suggesting cellular cooperation. These cell clusters resemble morphologically those found in vitro and in vivo in the course of immunisation processes.