Similarly, the IL-1 receptor antagonist gene, IL1RN, encodes IL-Ra that inhibits IL-1B activity by competitive binding to IL-1 receptors [19,20,21,22], which acts as an anti-inflammatory cytokine and may even favour osteogenic differentiation of gingival-derived mesenchymal stem cells (GMSC) [21], also shows statistically significant down-regulated expression (p = 0.048) in the group of PD+IR+ patients. The gene discussed is IL1RN; the disease is Parkinson disease.