Immunogenetics of peripheral arteriopathies

Takayasu's arteritis (TA) and thrombangiitis obliterans (Buerger's disease) are idiopathic, inflammatory arteriopathies with strong indications for the involvement of autoimmunity and host genetic factors in their immunopathogenesis. The exact etiology of these arteriopathies still remains unknown even after almost nine decades of their description. A series of immunogenetic studies conducted worldwide seeking to define genetic factors in governing immune response in these diseases have yielded conflicting results on the involvement of HLA molecules. While an association of HLA-B5 or its molecular subtypes with Takayasu's arteriitis has been emphasized in patients from Japan, Korea and India, no such association has been reported in Mexican and North American patients. On the other hand, a limited data is available on the association of HLA antigens with Buerger's disease. In this article, we provide an overview of the immunogenetics of Buerger's disease and Takayasu's arteriitis in the context of studies in North Indian patients and those in other ethnic groups. Our studies indicate a positive association of Takayasu's arteriitis with the HLA-B5 molecule with no preferential association with its two major subtypes. In Buerger's disease, we have observed a strong positive association with HLA-DRB1*1501 consistent with the findings in Japanese patients. These results suggest an important role of HLA linked factors in governing susceptibility to both arteriopathies.