TNF and infection: In addition to active inflammation, the spread of infection caused by the BAL procedure, atelectasis, and pulmonary injury induced by the washout of pulmonary surfactant (Lachmann, Robertson & Vogel, 1980; Russ et al., 2016) and the elevation of inflammatory cytokines, such as IL-6 and TNF α, in the blood and BAL fluid (Krause et al., 1997; Terashima et al., 2001) may be involved in the occurrence of BAL-DDs.