TNF and primary biliary cholangitis: However, there was a significant negative correlation between IL-13 and both IL-1β (r = −0.507, p = 0.003) and TNF-α (r = −0.390, p = 0.032) and positive correlation between IL-13 and E3 (r = 0.572, p = 0.0007) in PBC patients at an age of diagnosis above 65 (see Table 1).