A pan‐inflammatory microRNA‐cluster is associated with orbital non‐Hodgkin lymphoma and idiopathic orbital inflammation

Non‐Hodgkin orbital lymphoma (NHOL) and idiopathic orbital inflammation (IOI) are common orbital conditions with largely unknown pathophysiology that can be difficult to diagnose. In this study we aim to identify serum miRNAs associated with NHOL and IOI. We performed OpenArray (®) miRNA profiling in 33 patients and controls. Differentially expressed miRNAs were technically validated across technology platforms and replicated in an additional cohort of 32 patients and controls. We identified and independently validated a serum miRNA profile of NHOL that was remarkably similar to IOI and characterized by an increased expression of a cluster of eight miRNAs. Pathway enrichment analysis indicated that the miRNA‐cluster is associated with immune‐mediated pathways, which we supported by demonstrating the elevated expression of this cluster in serum of patients with other inflammatory conditions. The cluster contained miR‐148a, a key driver of B‐cell tolerance, and miR‐365 that correlated with serum IgG and IgM concentrations. In addition, miR‐29a and miR‐223 were associated with blood lymphocyte and neutrophil populations, respectively. NHOL and IOI are characterized by an abnormal serum miRNA‐cluster associated with immune pathway activation and linked to B cell and neutrophil dysfunction.