Antibodies to mycobacterial stress protein in patients with orofacial granulomatosis.

Immunoglobulin G antibody titers to the mycobacterial stress protein with molecular weight of 65 kDa (mSP65) were determined by ELISA in sera from 10 patients with orofacial granulomatosis (OFG). Four patients with confirmed Crohn's disease had serum antibodies to mSP65 with titers ranging from 400-950. Of six remaining patients, three patients had serum antibodies to mSP65, with titers ranging from 180-850, whilst no serum antibody to this antigen could be detected in 3 patients. However, other laboratory investigations failed to show any consistent pattern of disturbance in the 10 tested. Thus, the presence of serum antibody to mycobacterial 65 kDa stress protein might prove to be of a diagnostic value for Crohn's disease.