Genetics and immunodysfunction underlying Behçet's disease and immunomodulant treatment approaches

Behçet's disease (BD) is a chronic autoimmune condition primarily prevalent in populations along the Mediterranean Sea. The exact etiology of BD has not been fully explained yet, but the disease occurrence is associated with a genetic factor, human leukocyte antigen (HLA)-B51 antigen. Among the various immunodysfunctions that are found in BD, patients are increased neutrophil motility and superoxide production, as well as elevated production of tumor necrosis factor (TNF)-α and decreased production of interleukin (IL)-10. Elevated levels of inflammatory cytokines like IL-1 and IL-17 in BD have been found associated with aberrant expression of microRNA. Gene polymorphisms in BD patients have been observed in molecules involved in responses to pathogens that can ultimately modulate the host antimicrobial response. Moreover, several single nucleotide polymorphisms (SNPs) have been reported in genes encoding chemokines and adhesion molecules; many of these changes manifest as increases in vascular inflammation and vascular damage. Lastly, genetic and epigenetic changes have been suggested as involved in the pathogenesis of BD. Modifications in DNA methylation have been found in BD patient monocytes and lymphocytes, leading to adverse function of these cells. This review presents a comprehensive compilation of the literature with regard to the immunodysfunction underlying BD, as well as of the genetics, newly described clinical specifications and novel treatment strategies using immunomodulants based on the current understanding of BD.