Dina Mohamed Mekawy - Medical Biochemistry & Molecular Biology, Faculty of Medicine, Cairo University, Egypt & Medical Biochemistry and Molecular Biology, Faculty of Medicine, Badr University, Egypt.
Mervat Eissa - Rheumatology Department, Faculty of Medicine, Cairo University, Egypt.
Noha Adly Sadik - Internal medicine Faculty of Medicine, Cairo University, Egypt.
Rana Mohamed Abd-Elrahman - Medical Biochemistry & Molecular Biology, Faculty of Medicine, Cairo University, Egypt.
Ahmed Fawzy - Medical Physiology, Faculty of Medicine, Cairo University, Egypt.
Marwa Fathy Amer - Medical Biochemistry & Molecular Biology, Faculty of Medicine, Cairo University, Egypt.

Background: Vitamin D (vit D) controls inflammation and immunity. In Behçet’s disease (BD), microRNA-۱۵۵ is recognized as a significant immune response regulator. We aimed to investigate the role of vit D on immunomodulation and downregulation of inflammatory pathways associated with BD and detect the role of miRNA-۱۵۵ in BD. Methods: miRNA-۱۵۵ expression by Real Time -Polymerase Chain Reaction (RT-PCR), and vit D, nuclear factor Kappa-light-chain-enhancer of activated B cells (NF-κB), and Tumor necrosis fact of TNF-α) expression by Enzyme Linked Immunosorbent Assay (ELISA) were assessed. Results: BD patients had a significantly higher relative expression of microRNA-۱۵۵ (P< ۰.۰۰۱), it was significantly related to vascular manifestations (P< ۰.۰۰۱). Vit D relative expression was significantly low in BD (P< ۰.۰۰۱). There was a significant rise in miRNA-۱۵۵ in the active group compared to the inactive group (P< ۰.۰۰۱). A significant decrease in vit D levels (IU) was found in inactive and active individuals suffering from BD when compared to controls (P< ۰.۰۰۱). A significant rise was found in vit D levels in inactive BD cases (P< ۰.۰۰۱). A significant positive correlations were found between miRNA-۱۵۵, NF-κB, TNF-α, and negative correlations with vit D relative expression in BD patients. Conclusions: miRNA-۱۵۵ relative expression is higher in BD is significantly related to vascular manifestations. It may have a relationship to disease activity. Vitamin D relative expression is significantly low in BD patients, which can significantly influence immunomodulatory BD therapy. Vitamin D deficiency linked to active BD.

miRNA-۱۵۵, Reverse Transcriptase Polymerase Chain Reaction Behçet’s disease, Vitamin D.