Which immune cells predominantly comprise chronic inflammation?

Chronic inflammation is primarily characterized by the presence of persistent immune responses that lead to sustained tissue damage and repair. Among the key players in chronic inflammation are macrophages, which are integral to the process. They arise from monocytes and are responsible for phagocytosing pathogens and debris, releasing cytokines that regulate immune responses, and facilitating tissue repair.

The predominant cell types found in chronic inflammatory lesions are indeed macrophages and mononuclear cells, which include lymphocytes and plasma cells. These cells contribute to the ongoing nature of chronic inflammation. Unlike acute inflammation, which is typically marked by the influx of polymorphonuclear leukocytes (neutrophils), chronic inflammation shows a shift toward the accumulation of macrophages, thereby driving the ongoing immune response and repair mechanisms in tissues.

In context, while polymorphonuclear leukocytes are crucial during the acute phase of inflammation, they do not play a predominant role in chronic inflammation, where the ongoing immune and repair processes are primarily mediated by macrophages and mononuclear cells. Understanding the shift from neutrophil-dominant acute inflammation to macrophage-dominant chronic inflammation is essential in recognizing how the immune response adapts in different inflammatory states.