Expression of beta 1 integrins in IgA nephropathy.
OBJECTIVE
To compare the expression of beta 1 integrins in renal biopsies from patients with IgA nephropathy with that found in normal human kidney.


METHODS
Thirty renal biopsies from patients with IgA disease plus six control specimens were stained with monoclonal antibodies directed against the alpha 1, alpha 2, alpha 3, alpha 4, alpha 5, alpha 6, alpha v, and beta 1 integrin chains using the alkaline phosphatase anti-alkaline phosphatase (APAAP) technique. The intensity of integrin expression was graded semiquantitatively by a pathologist unaware of the antibody used.


RESULTS
Glomerular crescents stained strongly for alpha 3, alpha v, and beta 1, but integrin expression was greatly reduced or absent in fibrotic glomeruli. There were no alterations in the intensity of mesangial cell staining for any of the integrins tested. There was accentuated staining for the alpha 2, alpha 5, alpha v, and beta 1 chains in areas of interstitial scarring plus alpha 2, alpha 3, alpha v, and beta 1 on damaged tubules. Inflammatory cells expressed alpha 4, alpha 5, and beta 1.


CONCLUSIONS
In IgA nephropathy the interstitium is the main site of altered beta 1 integrin expression. Glomerular crescents also express several beta 1 integrins, but we found no differences in the intensity of integrin expression on mesangial cells. Altered beta 1 integrin expression may play a role in tubulointerstitial scarring in IgA disease. Thus modulation of integrin expression might attenuate this process.
Hillis
G S
GS
Department of Medicine & Therapeutics, University of Aberdeen.
Roy-Chaudhury
P
P
Duthie
L A
LA
Stewart
K N
KN
Brown
P A
PA
Simpson
J G
JG
MacLeod
A M
AM
D000911:Antibodies, Monoclonal; D005922:Glomerulonephritis, IGA / Q000276:immunology*; D006801:Humans; D007150:Immunohistochemistry; D019012:Integrin beta1 / Q000032:analysis*; D007668:Kidney / Q000276:immunology; D007678:Kidney Glomerulus / Q000276:immunology; D007684:Kidney Tubules / Q000276:immunology
D000911:Antibodies, Monoclonal; D019012:Integrin beta1