Which cells are primarily involved in the formation of granulomas?

Granulomas are structured aggregates of macrophages that typically occur in response to chronic inflammation or persistent infections. The hallmark of granuloma formation is the transformation of macrophages into epithelioid cells, which have a more cuboidal or epithelial-like appearance. These cells aggregate to form the core of the granuloma, often surrounded by lymphocytes and sometimes eosinophils, but the primary cell type involved in the formation and maintenance of granulomas is indeed macrophages.

Macrophages play a critical role in recognizing and capturing antigens, such as pathogens or foreign substances, and they produce a variety of cytokines and growth factors that are essential for the recruitment and activation of other immune cells. In the context of granulomas, they take on a specialized phenotype that allows them to manage chronic inflammatory responses, particularly in diseases like tuberculosis, sarcoidosis, and other granulomatous conditions.

Understanding the role of macrophages in granuloma formation highlights their importance in chronic immune responses and the body’s attempt to wall off and contain potential pathogens or irritants that cannot be easily eradicated, distinguishing them from other cell types such as neutrophils, lymphocytes, or eosinophils, which have different roles in the immune response.