Monocyte production during inflammation.

The majority of the resident macrophages in non-inflamed organs and serous cavities derive from circulating monocytes, but a small proportion originate from immature mononuclear phagocytes that only divide once in the tissues and originate from the bone marrow as well. During an acute inflammation the number of circulating monocytes increases, and a large proportion of these cells migrate to the site of inflammation and differentiate into exudate macrophages. The monocyte production during an acute inflammation is controlled by humoral factor, FIM, which is a protein that is synthesized and secreted by macrophages at the site of inflammation.