CD4 and tuberculosis: In the TB granulomas, infected phagocytes (such as monocyte-derived macrophages, foamy macrophages, multinucleated giant cells and neutrophils) are confined to a central core, which is surrounded by macrophages that develop an epithelioid phenotype (epithelioid macrophages) and a secondary surrounding layer composed mainly of lymphocytic cells (mainly CD4+ T, CD8+ T and B lymphocytes).