The Involvement of Apoptosis Inhibitor of Macrophage in the Disease Severity of Primary Biliary Cholangitis

<b>Background</b>: A protein called 'apoptosis inhibitor of macrophage (AIM)' is involved in the pathogenesis of obesity-associated disease. Although it is widely recognized that concurrent obesity affects the disease progression of chronic liver disease, as does concurrent type 2 diabetes mellitus (T2DM), the involvement of AIM in the pathogenesis of obesity or insulin resistance is not yet understood in patients with primary biliary cholangitis (PBC). <b>Methods</b>: Obesity was defined as a body mass index (BMI) exceeding 25, and insulin resistance was defined as a homeostasis model assessment for insulin resistance (HOMA-IR) value exceeding 2.0, respectively. Hepatic steatosis was estimated based on the classification proposed by Brunt and colleagues. The histological stage was determined by Scheuer's classification. <b>Results</b>: Twelve (25.0%) of the forty-eight PBC patients had concurrent obesity, and seven (14.6%) had concurrent T2DM. The PBC patients with obesity had significantly higher frequency of hepatic steatosis. Compared to the patients without T2DM, those with concurrent T2DM had significantly higher serum ALT levels and more advanced histological stages. The patients' serum AIM levels were not associated with concurrent obesity or concurrent T2DM. Our analyses identified the following as the factors that significantly affected the patients' AIM levels: serum immunoglobulin G, albumin, tumor necrosis factor-α levels, and the histological stages. <b>Conclusions</b>: These results indicate that AIM may not be involved in obesity or insulin resistance, but it may be associated with the disease severity of PBC.