TNF and pneumonia: Despite of the negative effects of TNFR1 on ENaC, the lower affinity of TNF for oligosaccharides in glycoproteins than for its membrane-associated TNF receptors (Hession et al., 1987; Sherblom et al., 1988) and the much higher expression level of TNF receptors than of ENaC in alveolar epithelial cells, an intriguing observation is that inhibition of TNF with a neutralizing antibody worsened edema formation in a rat pneumonia model (Rezaiguia et al., 1997).