Lysosomal membrane protein 2 (LAMP-2) is a target of antineutrophil cytoplasmic autoantibodies (ANCA) in addition to the more commonly known targets proteinase 3 and myeloperoxidase.
The prevalence of anti-LAMP-2 antibodies and their relationship to disease in ANCA glomerulonephritis are not well described.
We measured anti-LAMP-2 reactivity in 680 sera samples (two academic centers) from patients with ANCA glomerulonephritis (n=329); those with ANCA-negative glomerulonephritis (n=104); those with fimbriated, gram-negative Escherichia coli urinary tract infection (n=104); disease controls (n=19); and healthy volunteers (n=124). With levels in healthy controls used to define a reference range, anti-LAMP-2 reactivity was present in 21% of ANCA sera from two of the centers; reactivity was present in 16% of the control group with urinary tract infection.
Western blotting and immunofluorescence microscopy did not verify positivity.
Titers of anti-myeloperoxidase and anti-proteinase 3 antibodies were 1500-fold and 10,000-fold higher than anti-LAMP-2 titers, respectively.
There was no correlation between anti-LAMP-2 antibodies and disease activity. Furthermore, Wistar Kyoto rats injected with anti-LAMP-2 antibodies did not develop glomerulonephritis.
In conclusion, antibodies that react with LAMP-2 may exist at very low titers in a minority of patients with ANCA disease.
These data do not support a mechanistic relationship between anti-LAMP-2 antibodies and ANCA glomerulonephritis.
2012-03-01
Eng.
Journal of the American Society of Nephrology : JASN
University of North Carolina Kidney Center, Department of Medicine, Division of Nephrology and Hypertension, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA. ajroth [at] med.unc.edu
J Am Soc Nephrol. 2012 Mar;23(3):545-55
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