proteomic analysis reveals an increase of neutrophils and th17-related proteins expression in severe nodular acne lesions of the back

Background: the etiology and different inflammatory steps associated with the development of an acne nodule remain unsolved. objectives: this study aimed to investigate the main biological processes involved in acne nodules and compare them to those of papules. methods: nodules, papules, and non-involved skin of the back (control) were biopsied to perform proteomic analysis using mass spectrometry, luminex assay, and elastase staining on skin sections. results: many factors involved in the migration and function of immune cells, particularly those impacting leukocytes and neutrophils, were strongly and significantly higher in nodules than in papules and non-involved skin, while several enzymes involved in lipid metabolism were lower. elastase staining confirmed strong neutrophil infiltration within and around the nodules. conclusions: our results highlight the role of neutrophils during nodule formation in severe nodular acne of the back.