Recent advances in Takayasu arteritis

Takayasu arteritis (TAK) is a relatively rare systemic vasculitis mainly affecting the aorta and its large branches. While patients with TAK are more frequently observed in Asian countries, we can find patients with TAK all over the world. This limited number of patients has made it difficult to collect large numbers of patients and perform detailed studies. However, recent progresses have led to the identification of susceptibility genes and novel susceptibility human leukocyte antigen (HLA) alleles as well as accumulation of clues for the pathophysiology of TAK. IL12B was shown to be a susceptibility gene beyond ethnicity. MLX and FCGR2A/3A were shown to be associated with TAK in Japanese and Turkish/American populations, respectively. HLA-B*52:01 and *67:01 are susceptibility alleles to TAK, and the 171st and 67th amino acid residues of HLA-B protein are suggested important for TAK susceptibility. HLA-DQB1/DRB1 is recently reported as an independent susceptibility locus. Although there are no standardized serum markers or composite measures for disease activity of TAK, Japanese and Italian groups showed pentraxin 3 as a novel biomarker for detecting and monitoring patients with TAK. Recently, an Indian group proposed a novel scoring system called ITAS to evaluate disease activity of TAK. Standardization of assessing disease activity would lead to clinical studies with high quality. Several groups reported results of treatment for refractory TAK with biological agents targeting tumor necrosis factor or interleukin-6R. The recent accumulation of research data should improve understanding of the basic pathophysiology of TAK and lead to better management of patients with TAK.