Disease association ofantibodies tohumanand mycobacterial hsp7Oandhsp6Ostress proteins

SUMMARY Structural homology between microbial andhumanstress proteins hasbeenpostulated tobeabasis forautoimmunization inchronic inflammatory diseases. Therefore, weestimated byELISAtitration theantibody levels tomycobacterial (M)andhuman(H)recombinant hsp70 andM-hsp65 heatshockproteins inseraofpatients withCrohn's disease (n=29), ulcerative colitis (n=20)andnontuberculous mycobacterial disease ofthelungs (n=20). Antibodies toH-hsp60, separated bytwodimensional gelelectrophoresis, weretested insix seraofeachgroupofpatients. InCrohn's disease, antibody titres totheM-hsp65 antigen without detectable H-hsp60 binding weresignificantly elevated in52%ofthepatients. Incontrast titres tobothM-hsp70 andH-hsp70 weredemonstrable andcorrelated, butincreased overcontrol values only infour (14%) patients. Theantibody pattern in ulcerative colitis wasfound tobequite different: anti-H-hsp60 binding wasdemonstrable inmost patients, although anti-M-hsp65 titres werenotelevated. Furthermore, 25% ofpatients had significantly elevated titres toM-hsp70, butnottoH-hsp70. Innon-tuberculous mycobacterial pulmonary disease, about 500%ofpatients hadelevated titres tobothhsp65 andhsp7l mycobacterial antigens butnottothecorresponding humanproteins; patients withMycobacterium xenopi infection hadthehighest titres inthis group. Theseresults demonstrate theexistence ofdistinct diseaseassociated patterns inthehumanantibody response tostress protein antigens. However, these data arenotsufficient toimply sensitization withmycobacteria inpatients withinflammatory bowel diseases, since certain epitopes ofheat-shock proteins areshared byseveral bacterial genera.