{Reference Type}: Journal Article
{Title}: Expression of CD163 and major histocompatibility complex class I as diagnostic markers for idiopathic inflammatory myopathies.
{Author}: Ghang B;Nam SH;Choi W;Kim HJ;Lee J;Lim DH;Ahn SM;Oh JS;Hong S;Kim YG;Lee CK;Kim J;Yoo B;Nam SJ;
{Journal}: Arthritis Res Ther
{Volume}: 26
{Issue}: 1
{Year}: 2024 Jul 30
{Factor}: 5.606
{DOI}: 10.1186/s13075-024-03364-z
{Abstract}: <B>BACKGROUND: </B>To develop an inflammation-related immunohistochemistry marker-based algorithm that confers higher diagnostic ability for idiopathic inflammatory myopathies (IIMs) than IIM-related histopathologic features.<BR><B>METHODS: </B>Muscle biopsy tissues from 129 IIM patients who met the 2017 EULAR/ACR criteria and 73 control tissues from patients with non-inflammatory myopathies or healthy muscle specimens were evaluated for histological features and immunostaining results of CD3, CD4, CD8, CD20, CD68, CD163, MX1, MHC class I, MHC class II, and HLA-DR. Diagnostic algorithms for IIM were developed based on the results of the classification and regression tree (CART) analysis, which used immunostaining results as predictor variables for classifying patients with IIMs.<BR><B>RESULTS: </B>In the analysis set (IIM, n = 129; control, n = 73), IIM-related histopathologic features had a diagnostic accuracy of 87.6% (sensitivity 80.6%; specificity 100.0%) for IIMs. Notably, muscular expression of CD163 (99.2% vs. 20.8%, p < 0.001) and MHC class I (87.6% vs. 23.1%, p < 0.001) was significantly higher in the IIM group than in controls. Based on the CART analysis results, we developed an algorithm combining CD163 and MHC class I expression that conferred a diagnostic accuracy of 95.5% (sensitivity 96.1%; specificity 94.5%). In addition, our algorithm was able to correctly diagnose IIM in 94.1% (16/17) of patients who did not meet the 2017 EUALR/ACR criteria but were diagnosed as having IIMs by an expert physician.<BR><B>CONCLUSIONS: </B>Combination of CD163 and MHC class I muscular expression may be useful in diagnosing IIMs.