Raised agalactosyl IgG and antimycobacterial humoral immunity in Takayasu's arteritis

Takayasu's arteritis is an inflammatory occlusive disease of the aorta and its main branches of unknown etiology. Some suggested causes include inapparent infection with Mycobacterium tuberculosis, or autoimmunity evoked by this organism. We have therefore sought links with mycobacterial disease.

We assayed the % agalactosyl IgG, antibody to a tuberculosis-specific 38 kDa protein, and antibody to the mycobacterial 65 kDa heat shock protein (HSP), in patients with active or inactive Takayasu's arteritis, in whom the diagnosis of tuberculosis was excluded. The results were compared with findings in tuberculosis (positive controls), normal donors and patients with Wegener's granulomatosis.

The % agalactosyl IgG in patients with active arteritis was in the range previously seen only in rheumatoid arthritis, Crohn's disease, and the mycobacterioses. Similarly, significantly raised antibody to the purified 38-kDa protein of M. tuberculosis, and to the 65-kDa HSP of M. leprae, was found in 78% of patients with Takayasu's arteritis, and the levels were higher in those with active disease.

These results suggest that Takayasu's arteritis particularly clearly illustrates the occasional relationship between mycobacteria and diseases of superficially autoimmune pathogenesis.