Sera from patients with anti-GBM nephritis including goodpasture syndrome show heterogenous reactivity to recombinant NC1 domain of type IV collagen alpha chains.
BACKGROUND
Goodpasture (GP) syndrome is defined by the clinical association of pulmonary haemorrhage with rapidly progressive glomerulonephritis. The disease is caused by pathogenic autoantibodies directed against type IV collagen, which is a major structural component of glomerular basement membranes (GBM).


METHODS
The non-collagenous domains (NC1) of all six human type IV collagen alpha chains was produced in E. coli as recombinant fusion proteins with glutathione-S transferase. Sera from 10 patients with different types of anti-GBM nephritis, including GP syndrome, were tested for reactivity with the six proteins using immunoblotting of denatured and reduced proteins and ELISA without reduction.


RESULTS
All 10 sera reacted with the alpha 3 (IV) collagen chain by immunoblotting and ELISA. One serum also recognized the alpha 2(IV), alpha 4(IV), alpha 5(IV) and alpha 6(IV) chains by immunoblotting. ELISA measurements revealed reactivity of several other sera with alpha 2(IV), alpha 4(IV) or alpha 6(IV) but not with alpha 5(IV) collagen chains. No reactivity was observed with the alpha 1(IV) chain.


CONCLUSIONS
Autoantibodies in anti-GBM nephritis may not be directed only against the alpha 3(IV) collagen chain and they frequently recognize conformational epitopes.
Dehan
P
P
Biocenter Oulu, University of Oulu, Finland.
Weber
M
M
Zhang
X
X
Reeders
S T
ST
Foidart
J M
JM
Tryggvason
K
K
D000328:Adult; D000368:Aged; D019867:Anti-Glomerular Basement Membrane Disease / Q000097:blood* / Q000276:immunology; D001323:Autoantibodies / Q000097:blood*; D015415:Biomarkers; D003094:Collagen / Q000235:genetics / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D015151:Immunoblotting; D008297:Male; D008875:Middle Aged; D011994:Recombinant Proteins / Q000276:immunology
D001323:Autoantibodies; D015415:Biomarkers; D011994:Recombinant Proteins; D003094:Collagen