Aschoff cells are -
The monocytes migrate to tissues and become part of the tissue (fixed) macrophages.
Blood macrophages → Monocytes
Tissue macrophages → Histiocytes

Tissue macrophages (histiocytes) in different tissue are mentioned below –

Lung: ‘Alveolar macrophages’ or ‘Dust’ cells
Placenta: Hofbauer cells
Brain: Microglia
Kidney: Mesangial cells
Liver: Kupffer cells
Spleen: Littoral cells
Bone: Osteoclasts
Synovium: Type-A lining cells
Skin: Langerhans cells
Spleen: Red pulp sinusoidal lining cells
Connective tissue: Histiocytes (tissue macrophages)
L The lifespan of monocytes in circulation is 1-3 days whereas tissue macrophages have a life span of 3 months to years
Fibroblasts
Monocytes
Neutrophils
Lymphocytes