miRNAs are small non-coding RNA molecules that participate through silencing in post-transcriptional regulation of gene expression. Recent studies have highlighted the importance of microRNAs (miRNAs) as regulators of both the innate and the adaptive immune response. There are emerging data regarding the role of miRNAs in patients with Systemic Lupus Erythematosus (SLE). One of the main stimuli for the induction of miR-21 is hypoxia. Moreover, the expression and function of miR-210 is directly related to the activity of “hypoxia inducible factor-1a”(HIF-1a). The aim of the study is to examine the regulation of miR-21 and mir-210 in patients with SLE based on the hypothesis that cellular hypoxia may have an important role in SLE pathogenesis. Plasma, PBMC and urine samples will be collected from patients with SLE and normal controls. miR expression will be studied with real-time PCR. Functional experiments will examine the effect of miR-21 and miR-210 on HIFa and ERK1/2 και PI3K/AKT signalling pathways. The study will provide novel data regarding the expression and the role of miR-21 and miR-210 in patients with SLE. The results of the study will contribute to a better understanding of miR network regulation in SLE in order to ultimately identify molecules that can be used in clinical practice as diagnostic or prognostic markers, treatment response markers, or even as potential future therapeutic targets.