TNF and infection: In the synovial samples, we also quantified, via enzyme-linked immunosorbent assay (ELISA), the concentration of cytokines, such as IL-6, which is an inflammatory cytokine used for the diagnosis of PJI; TNF-alpha, which is produced more by macrophages involved in the acute phase of infection and associated with T-cell activation; CXCL10, a cytokine produced in response to interferon-gamma activation; and IL-10, which is an anti-inflammatory mediator.