AUTHOR=Ma Xue , Huo Kaikai , Gao Huajie , Ge Huizhen 

TITLE=The clinical value of lymphocyte percentages and the monocyte-to-lymphocyte ratio in differentiating immune-mediated necrotizing myopathy from dermatomyositis

JOURNAL=Frontiers in Neurology

VOLUME=Volume 16 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2025.1581206

DOI=10.3389/fneur.2025.1581206

ISSN=1664-2295

ABSTRACT=ObjectiveImmune-mediated necrotizing myopathy (IMNM) and dermatomyositis (DM) represent distinct subtypes of idiopathic inflammatory myopathies (IIMs). While both conditions share clinical manifestations, including muscle weakness and inflammatory infiltrates on muscle biopsy, their pathophysiological characteristics differ significantly. This study investigated the clinical utility of hematological inflammatory biomarkers in differentiating these two entities.MethodsIn this retrospective analysis, we compared complete blood count parameters among 27 patients with IMNM, 14 patients with DM, and 85 healthy controls (HC). Demographic characteristics, clinical presentations, and hematological indices including the neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), and platelet-to-lymphocyte ratio (PLR) were analyzed.ResultsMyalgia and skin rash were observed more frequently in the DM group compared to the IMNM group. The patients with IMNM exhibited significantly higher serum creatine kinase (CK) and lactate d0.2815ehydrogenase levels. Red blood cell distribution width (RDW), monocyte counts, and MLR were elevated in the patients with IMNM compared to the HC. The patients with DM showed significantly increased neutrophil percentages, monocyte percentages, monocyte counts, NLR, MLR, and PLR, as well as decreased lymphocyte percentages and counts, compared to the HC. When directly comparing DM and IMNM, the patients with DM had lower lymphocyte percentages and counts, along with higher NLR and MLR. Receiver operating characteristic (ROC) curve analysis revealed that lymphocyte percentages and the MLR had moderate predictive value for differentiating IMNM from DM, with area under the curve (AUC) values of 0.709 and 0.7487, respectively.ConclusionRDW and the MLR in IMNM and the NLR, MLR, and PLR in DM represent accessible and cost-effective biomarkers for assessing inflammation. Lymphocyte percentages and the MLR may serve as inexpensive and readily available supplementary markers for distinguishing IMNM from DM.