Expression of circulatory microRNA-155 in non-Hodgkin lymphomas and rheumatoid arthritis

Background. Micro-ribonucleic acids (miRs) take part in post-transcriptional gene regulation. MiR-155 regulates hematopoiesis, oncogenesis, and immunologic and inflammatory processes. We investigated the expression levels of miR-155 in sera of patients with Burkitt’s lymphoma, diffuse large B-cell lymphoma (DLBCL), and rheumatoid arthritis. Methods. In this cross-sectional observation, we used real-time polymerase chain reaction to evaluate expression of miR-155 in sera of 92 Iranian adults who were healthy or had Burkitt’s lymphoma, DLBCL, or rheumatoid arthritis. The relative quantification of gene expression was calculated in terms of cycle threshold values (Ct). We conducted Pearson’s and Spearman’s correlations, Fisher's exact test, and one-way analysis of variance and Games-Howell post-hoc test, with the level of significance of 0.05. Results. The expression of miR-155 was independent of sex and age in each study group. In comparison with healthy subjects (-ΔCt: -2.29 [±standard deviation: 1.92]), miR-155 expression increased in DLBCL (2.49 [±1.01]), and rheumatoid arthritis (2.30 [±1.34]) patients, but did not change in adults with Burkitt’s lymphoma (-1.29 [±2.11]). Conclusion. MiR-155 was significantly elevated in the sera of patients with DLBCL, and rheumatoid arthritis. Further studies with larger sample sizes are needed to assess the diagnostic, and therapeutic applications of miR-155 in these patients. Practical Implications. The expression of miR-155 increases in sera of patients suffering from DLBCL, and rheumatoid arthritis. The expression of miR-155 was independent of sex and age of patients in this study.